Updated Alternator/Starter cable

Hi guys, Just want to let you know the updated cable from Porsche (P/N 99660701903) is really nice ($40 from Sunset Porsche). My old cable is heavily corroded at the started end. I discovered it by doing a voltage drop test on that cable under load (a/c and low beam ON) and found I lost ~0.5V on that 3 ft cable (@54A)! My voltage gauge reading would sometimes drag down to a hair below 13V when I had heavier load ON. Now with the new cable, I only lose 50mV on that same cable and my voltage stays at ~13.4v even with heavy load. I highly recommend the new cable even though it's a bit of a pain to replace it. I also replaced my voltage regulator with F00M-144-136 from Pelican and it works just fine. There's nothing wrong with my old one F00M-145-350 but I figure since I have it apart, I may as well replace it and leave the old one as a spare. IMAG1372 (Large).jpg IMAG1374 (Large).jpg IMAG1376 (Large).jpg IMAG1383 (Large).jpg IMAG1384 (Large).jpg IMAG1386 (Large).jpg

Great pics! And good info.

Ahsai, I have the exact same issue. Thanks for posting the part number. Did you,get your part from a dealership? More importantly, did you have to remove the A/C compressor to get the cable out and the new one in? Doesn't look like the terminal will fit around otherwise. Thanks.

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I got my cable from Sunset Porsche ($40 + shipping) and yes, you have to remove the a/c compressor. I didn't need to remove the starter and the following steps worked for me: - remove the airbox, drive belt, then the alternator - remove cable from alternator - peel back the thick rubber sleeve on the starter +ve terminal then remove the connection nut using very long extension - remove the throttle body - unscrew the power steering fluid reservoir cap then rotate (not remove so no fluid loss) the reservoir anti-clockwise to make room for a/c compressor removal - remove the a/c compressor (3 bolts. Bolts will stay on the compressor. One bolt at the back that can be seen by an inspection mirror. Remove the engine compartment temp sensor with the rubber grommet between the 4&5 intake runners and put an extension there). The compressor only needs to come out slightly to create clearance for the bulky jump start terminal to pass - there's a plastic bracket in the middle of the cable that snaps and locks onto a palstic tab which in turn mounts on the engine. Cut the old plastic bracket with a pair of dikes but make sure you don't damage the tab the bracket locks onto. - cut the zip tie that's in the middle of the cable - remove the cable from the left of the engine bay Install is the reverse except snap the plastic bracket onto the tab only at the final step because it's virtually impossible to disengage it once it's locked in, except destroying it.

Thanks for the detailed instructions! I got to the 3 bolts on the compressor and loosened them all (removed one of the front ones and the smaller 10mm under the temp sensor). I'm having a tough time getting the compressor to move forward. Was it a pain or am I missing something? I literally can barely budge it.

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Did you rotate the power steering pump reservoir to create clearance?

Ahsai, How long are the old regulator brushes? Pic? How many miles?

Ahsai, I removed the wrong bolt which is why it wouldn't move! Found the correct one. Did you drain the steering fluid? I can't seem to rotate it more than 1/4" so I may drain and remove it.

Got it done. The replacement cable will take a few days to get here so in the meantime I hit the corroded cables with battery cleaner and wrapped them with electrical tape. Reattached everything and it started right up! Thanks for your help.

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Hey Frank, it had 3yrs and 20k miles on them and have plenty of life left. The regulator was still working fine.

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Glad you got it figured out. BTW, I didn't need to drain any power steering fluid. Just unscrewed the cap and rotated the reservior a bit. Come to think about it, you may need to pull out the reservoir neck a little bit before you can rotate it. Anyway, it's no big deal even if you have to drain some fluid. I'm sure you don't have to remove the reservoir to get clearance though.

Hi guys. Thanks for the info Ahsai. I have the same issue and am planning to follow your directions. Does anyone know if the updated cable from Porsche (P/N 99660701903) will fit a '99 cab? I've gone to some of the parts sites and its unclear. Sonnen is saying that I need part # 99660701901 (rather than 99660701903). Thanks!

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Glad my info helps. I highly recommend Sunset Porsche (Andraya - [email removed]) She will cross check the parts you order with your VIN to make sure the parts are 100% correct for your car. I think xxxx1901 is outdated and superceded by the 1903 but pls check with Andraya for a definitive answer. She'll be more than happy to help you.

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Thanks Ahsai. Those brushes seem to last ~80k miles. At least that is how long they lasted on two Mercedes MLs that I had. The Alternator was the same Bosch part # on my 2004 ML350 as my 2003 996. These regulator #s fit. Not sure but the -225 and -350 might be different amp ratings. The -225 was in the Mercedes alternator but the -341 was in the Mercedes box??

Hey Frank, no idea how to decode these numbers. And agree the brushes last a long time. Most likely outlast the electrnics inside.

According to Sunset I need the P/N 99660701901 cable not 1903. Not sure why, but that's what I will order. I think it may be specific to older 996s ('99). I'm also going to replace the Alternator Regulator while I've got it all apart. I ordered F00M-144-136 from Pelican.

Makes sense. You should be good with those parts. Let us know how it goes.

I'm a good way (hopefully) through the process and am calling it a day. The Alternator was very hard to get out. I beat on the Upper bolt with a rubber mallet but could not get it free. I carefully used a pry bar and the Alternator finally came loose. Just maneuvering the Alternator out was tricky too. Now I'm halfway through getting the AC compressor out. Its amazing how much has to be done just to get a new cable in!

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I know! Trust me, it's worth it at the end

OK. Now I have a problem. I took the cover off of the Alternator so I could replace the Regulator. I then removed the two screws that hold the Regulator to the Alternator and.... both screws snapped! About 2mm of the screws were left on the heads (which came off). The rest of the screws are stuck in the Alternator body. Pretty frustrating. These are small screws. Not sure how to proceed. Any ideas anyone? Not sure I can drill them out without destroying the threads in the Alternator.

Have you tried to grab the screw with a vise grip plier? Can you dremel a straight slot on the screw and use a flat blade screwdriver? These screws should not be on that tight. Worst is you can use a left-hand drill bit to drill them out.

Btw, if you destroy the threads, you should still be able to retap the alt threads to one size bigger or even to the next std size (and use std screws instead of metric). Just need the screw head small enough to recess in the regulator.

Thanks Ahsai. The screws broke off down in the Alternator and are very small. I think I'm going to have to drill them out and retap the hole to a larger size.

OK. So I have successfully installed a new Alternator/Starter cable. I followed the directions here: http://www.renntech.org/forums/tutor...e-replacement/ with one BIG change. I was able to pull the cable out through the space between the AC compressor and the intake manifold (towards the charging pole) without loosening/removing the AC compressor. This is on a '99 996 cabriolet. I'm not sure if that is relevant or not as I know that some have not been able to do the same. The thing I realized was that in order to pull the cables through ( a Y with one cable going to the starter and one going to the Alternator) it was necessary to first route the part of the Y going to the Alternator through the space between the compressor and the intake. This served to put one part of the Y parallel with the lower part of the Y, making the entire cable "thinner". Its a bit hard to explain. Anyway, then I pulled on the cable that goes to the charging pole and the cable that goes to the Alternator (which at this point were together). With a bit of a tug the cable that goes to the Starter pulled though. I'm not sure if this will work for all cars but it worked for mine. Installation was just the reverse.

Nice work. Hows the voltage now?

OK. My electrical issues seem to be fixed. Unfortunately the car is now throwing some CEL codes: P0410 and P1411. I'm guessing I broke or dislodged something when I put the alternator back in.

Was the old cable just a mk1 issue or do 2002's have same issue ?

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Is the SAI pump connected? Do you hear it at start up?

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Same issue. I've replaced mine on my '03.

Yes. I hear the SAI pump run on start up. The strange thing is I did not get any error codes until the 3rd time or so I used the car after my repairs. I then cleared the codes and they came back after a few more uses. I cleared the codes again and am waiting to see if they come back. I'm wondering if the carb cleaner I used (generously) on the intake is causing the issue and is burning off. Hoping I dont have to take the Alternator out again although it should be much easier this time.

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Could be the vacuum line to the SAI valve got knocked off or the connection to the SAI valve is unplugged. This may help http://p-car.com/996/diy/sai/mainpage.html

This is a more comprehensive thread http://www.renntech.org/forums/topic...l-p0410-p1411/

Thanks. Wow this is frustrating. Digging a ditch and filling it up again...

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Now you can do it blindfolded though

Unfortunately you are right.

Bump to an older thread. I just did this fix today and used this trick: https://rennlist.com/forums/996-foru...implified.html The hot water worked perfectly. I have a '99 and did NOT have to remove the throttle body, intake plenum, or loosen the A/C compressor. This trick made this fix very simple, all things considered.

Thanks for posting this. I tried to add the link of that trick to my first post but I can no longer edit the post.

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I have to thank you and everyone who contributed to this thread. I am really grateful for the valuable information shared. I purchased a '99 996 C2 in October 2014. Less than 10k miles before I purchased the car, the engine was replaced on the car by the previous owner professionally with a complete rebuild using a '01 block, L&N Engineering Nickies upgrading the bore from 3.4L to 3.6L, forged pistons and their IMS upgrade. I had the exact problem happening on my car. Thinking it was the alternator, starter, voltage regulator, battery, etc., I was ready to endure a massive repair bill one way or the other. However, going through the service records carefully, I then recognizing that only 5,000 miles had passed since the alternator was replaced with a new one, I became suspicious... At that time, a new cable was installed and it was part number 99660701901...the older number Porsche had. Curious, I sprayed a little WD-40 on the contacts at the starter and the + jump pole of the cable and the voltage increased, at least when cold and then the resistance of the heat when the engine warmed up made the voltage drop just like all the rest of you experienced...I knew something else had to be going on. I too contacted Sunset Porsche and gave my VIN. I got the updated/upgraded part No. 99660701903...I had the parts specialist check and he indicated that he was aware of the other number but to go with this one....how right he was. It took about a week to get the part in. Just as you said, about $42! When bringing it back to the indie shop that had been servicing the car for the prior owner and actually did the engine rebuild, I brought the cable with me. Unlike other shops that whine about not wanting to install a 'customer provided part', since it was a genuine Porsche part, from a dealership no-less, they actually thanked me for having it. However, to be on the safe side, they ran all the electrical tests that confirmed our hunch. The alternator/voltage regulator, battery and starter were all good. Thereafter, the plan was to install the cable and then retest and if necessary do whatever else was needed. It turns out, nothing else was... The previous cable had actually 'melted' in certain areas...they apologized for using the older part 99660701901 when replacing the alternator for the previous owner because their supplier did not have the new part number 99660701903, which they admittedly stated had some noticeable differences at the terminals and a bit in the length. They say it happens a lot when an older part is sitting on a shelf and the supplier moves what they have... Makes me think that the changed configuration of the part and the trouble that we all share, the part should have been an optional recall. Overall, between the testing, removing of the old one, installation of the new one, retesting, and closing the project out, they put in about 4 hours but lucky me, I was charged for only 2.8 hours which is more than fair for the work done. My results are the same.... Once more, without the direction of your thread, and the contribution of all of you, I would not have had the insight to target the problem and arrive at a simple and cost effective solution. Thank you.

Glad to hear that this post actually helped! This problematic cable should be replaced whenever someone experiences a low voltage and/or cranking problem. Now with the latest smart hot water trick, replacement should be a snap.

I can't seem to find a difference between the 01 and 03 versions of this cable. My parts guy did a pretty extensive search on this and the -01 apparently isn't superseded by anything. Everything he could find said that the 03 cable is only for MkIIs. Needless to say, I installed the 01 on my '99.

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I have the same understanding as you. Looks like the -01 and -03 split at engine number 66309950 http://www.autoatlanta.com/porsche-p...section=902-05 My original cable ends with -02 so the -03 was an upgrade for me. Looks like the -01 is alredady the latest for MkI. Anyway, my -03 cable failed again in 1+ yr and I'm on my second -03 now! Looks like Porsche is still not getting it right despite the upgrade.

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Well at least you and I know how to do this fix pretty quickly now thanks to the new hot water trick!

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Jesse at Sunset Porsche actually ran my VIN...I have a '99 C2 and the rebuilt engine is from a '01 (04 6610...)-both would be considered MK1 models. He crossed referenced both parts and the cable ending in 03 was what was coming up on his computer. I specifically asked him about the 01 that was available and in the car but he insisted that the 03 cable is the proper one for me and I should order that one. Looking at the 2 cables, the contacts on the 03 cable seem to be broader and heavier a bit. The cable assembly seems to be a bit thicker and ever so slightly shorter than the 01... The end result is that the cable worked and I am getting normal voltages even under heavy loads.

Well here's something interesting. I kept the old, decrepit cable that I recently replaced. Just went out and looked at the part number on it. Yup, you guessed it: it's an -03. Here's a link to the pic of how bad that cable became. I don't know it's age but obviously it's been replaced before. http://www.renntech.org/forums/topic...eded/?p=266777 As Ahsai inferred above, it likely won't matter if it's an -01 or -03, the cable will continue to fail. It might be best to start making our own...

What do you think did that to your cable? 'farmer boy' indicated that he had a defective starter that he replaced and looking at the photo of the terminal you posted, looks to be the end at the starter. Do you think your starter has a short that caused that? Corrosion? Engine Temperature?

Answered on the RennTech thread.

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I trust Sunset completely so I have no doubt they sent you the right cable for your engine. Was just looking for some mapping between MkI,II and -01, -03. Wow, didn't know your failed cable was -03. Oh well, like you said, both versions fail. BTW, just found out the black plastic box at the cable end can be purchased separately for ~$6 (99661120101 porschepartshub) so no worries even if you mess up when trying to remove it. I still have the two failed cables from before so I already got 2 spares

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Maybe LN or Jake needs to update their product development or lineup to include bulletproof alternator cables too. LOL.

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and an SCG (Starter Cable Guardian) just to monitor for abnormal voltage drop...going to file a patent now (for the geeky, all you need is an opamp to compare the v out of the alternator and the voltage at the + jump post. If that exceeds 0.5v, sound the alarm haha)

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Excellent find!

Ashai- Thank you for the post again and your replies. YOU are the man! The work was done yesterday and I just came back from dinner with 90 degree weather in South Florida, A/C blowing, lights and sound system on, going about 13.5V now...better than dropping below 12V which was what was happening. Suncoast is a Porsche dealer and given the specs of my car, if they said I needed the 03, I agree they are probably right. Really, looking at the 01 and 03 side by side yesterday, the 03 seems to be a little more thick and the contacts seem to be a bit larger and thicker...maybe they designed the slight difference to hold a larger load? Not sure.

Based on the visual failure mode of the cable, it's a high resistance connection between the crimp and the cable conductor that degrades over time where it creates a large enough voltage drop to create head and voltage issues. The more it heats up, the more it drops voltage, the more it degrades. The new cable obviously has a different lug and they might use a different crimp die also to make the connection better. Over time, all connections will degrade, but it's a matter if this one will exceed the remaining life of your car. I read this whole post over and it's very informative....just another thing to add to my brain as my wallet has no memory at the present time!

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If the 2 cables are interchangeable, the newer one may very well be the 'improved' or most recent permutation of Porsche engineering... I liken the similarity to what I have heard about the different versions of the water pumps for our cars. I have heard that the Turbo and, for the life of me I cannot recollect the designation of a special edition engine that first appeared on the MK2, both have replacement water pumps with metal impellers rather than the plastic one in the typical stock models (C2 and C4). Now, that being said, assuming that the ones with the plastic impellers have a shorter life span, given my understanding that the two are pumps are essentially interchangeable, why not get the one with the metal impeller since they have a lower failure rate? Perhaps making the most recent version of the cable a thicker gauge, replacing heavier/larger contacts and making the cable have just a little shorter makes the 03 just a bit better than using the still available 01. I can only hope so... Still, it is pure speculation...

Interesting. I put the 01 cable in my 2002 and it worked great up until recently when the temp has recently increased here. I bought the cable last spring and I guess i have 20,000kms on it since then. I found that when really warm it hesitates on turn over. Ill see what the pcar dealer says about that v the ....03 cable and what they can do if anything.

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The one removed from my car was installed by the Indie at the same time the alternator was replaced about 5k miles ago! It was an 01 and I am in South Florida where it hot most of the time...that is the cable that failed and we just replaced same with the 03...working great and crossing my fingers that it will stay that way.

Ok, so now we've completed all the combinations between mkI, II and -01 and -03....and all of them failed. @Paul, the -03 is much thicker than the -02 (stock on my car) yet it still failed in 1+ yr with no visible corrosion, the wires were still shiny so that's yet another mystery. @lawyer, metal impellar is a bad idea as it will mill the engine block when the pump starts to fail and wobble. The stock composite material is fine and it lasts a long time (i would say 60k+ miles and 6+ yrs) @CDL, please keep us posted what the dealer find. I'm pretty sure your '02 should use the -03. Your cable should be covered by a 2yr warranty if they can determine that it has failed (by voltage drop test).

Check out 964Polar's ingenious way to replace the cable in this link. Not sure if I added this link before but before I forget, I added it here. https://rennlist.com/forums/996-foru...implified.html

Hey guys. I'm just about to order a cable for my 2002 C4 996. Its confusing which part to get, 99660701901 or 99660701903. Can someone confirm the 03 is the better cable and would work on my model. I think my alternator is on the way out as my voltage is constantly about 13.1V. I'd like to replace the cable at the same time. I'm also getting some trouble on hot starts once and a while.

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It won�t matter either way as either will eventually fail again. I�d personally recommend you just buy the one that�s appropriate for your VIN. Check the PET if you�re unsure.

Ok thanks. Well mine is 18 years old and still might be fine so hopefully it won't be necessary a second time. All of this work can be done from the engine bay correct? It looks like on 997 you need to go underneath the car, but not on the 996.

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Yup it can be done in the engine by removing the alternator. There�s a guide or two here on RL.

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I bought 996.607.019.03 based on an old thread here. The parts websites say it's not compatible with my ' 99 C2 but I can't see any difference except the '03' part has a plastic mounting clip in the middle of the larger gauge wire.

As is usual with Porsche, the 03 is an upgrade to 01 and should work without any problems. I think I read in this thread that a side-by-side comparison showed the 03 to have thicker cables, and that is better.

Can someone measure the length of each cable (the part going from starter to alternator and starter to the plastic joint box) and how thick each wire is (The thickness of the conductor). I was thinking that instead of installing a crappy factory cable that seems to last only a few years before resistance increases, a better solution would be to make 2 separate cables and joint them at the starter. At the starter can use two 90 degree lugs like this ( https://www.amazon.com/Fastronix-Degree-Tinned-Copper-Gauge/dp/B07ZN6VCMT/ref=sr_1_3?dchild=1&keywords=90+degree+tinned+cable+lugs&qid=1597671326&sr=8-3 https://www.amazon.com/Fastronix-Degree-Tinned-Copper-Gauge/dp/B07ZN6VCMT/ref=sr_1_3?dchild=1&keywords=90+degree+tinned+cable+lugs&qid=1597671326&sr=8-3 https://www.amazon.com/Fastronix-Degree-Tinned-Copper-Gauge/dp/B07ZN6VCMT/ref=sr_1_3?dchild=1&keywords=90+degree+tinned+cable+lugs&qid=1597671326&sr=8-3 https://www.amazon.com/Fastronix-Degree-Tinned-Copper-Gauge/dp/B07ZN6VCMT/ref=sr_1_3?dchild=1&keywords=90+degree+tinned+cable+lugs&qid=1597671326&sr=8-3 ). They can be stacked at the starter and tightened together. With a good crimp or solder joint this should work much better than Porsche factory cable. I know that these tinned cable lugs are frequently used in marine applications and as long as you use a good heat shrink tubing with adhesive on the end to protect the connection, they tend to last a very long time even in heavy salt water environment.

This is what I did, ordered cables made up from Battery Cables USA using Single Odd wire with 5/16 hole ends, ran the alternator charge cable to the post and one from the starter to the post, 2 feet long for both, then order a single Odd cable with 5/16 hole ends for my ground cable 1 foot long., 3 cables cost me less than 30 bucks delivered. https://www.batterycablesusa.com/?gc...BoCJd0QAvD_BwE

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I don't know how old mine is (2001 C4), but it's at least 15+ years old (I have service records since 2004). I just had it all apart as the slow crank symptom from a few months ago eventually progressed to no crank; it would just click. Fortunately, it turned out to be a loose nut on the starter side (my fault for not torquing it properly a few years ago when I serviced the starter). While there was no need, I refurbished/regreased the starter and cleaned up the alternator terminals while I had everything apart. The infamous Y cable looked fine--like new--no discolouration or heat marks whatsoever. To be safe, I sprayed some deoxit into the lugs, recrimped them with a punch and hammer, and liberally coated all the connections and crimp areas with silicone grease for good measure. I get 14V at battery terminals on cold start, and 13.4 when the car is hot (with a/c and headlights on). The crank is strong, starts right up, and the voltage drop from engine bay to +ve battery terminal in front is 0.1V when hot. Rabi

JohnCA58, Thanks for the info, very helpful. With 2 feet length, was there a significant amount of slack left on either cable? In doing this over, does it make sense to make one cable longer/shorter than another? Also, when stacking the 2 cables on the post, did they stack "nicely" or do they have to go crooked somehow since the lugs don't seem particularly stackable to me.

its been 2 years since did the job, cables did fit nicely, I did cover both cable with high heat split loom, I did fabricate a new bolt for the post, original just didn't have enough thread since there 3 cables at the post now,, did reuse the plastic housing removed from the old Y cable using hot water to remove,

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These are the measurments for cable # 996.607.019.03 This is a new cable so I wasn't cutting the insulation off wire to see the true diameter. This is the smaller cable dimension with insulation And the large one...

SoCal911T, thank you very much for the measurements, very helpful.