In line resistor

Does anyone know how to attach in-line resistor to bulbs or something. Cause I 'm trying to install LED bulbs and in-line resistor is needed to be attached to it, for it to work properly. Anyone has knowledge about it?

Assuming you can't buy an LED bulb that has a built in resistor (does anyone make those?) you'll have to cut the wires on your headlight harness and insert (solder, vampire clip, etc.) the resistor. It takes a basic knowledge of wiring, so if you've never worked on wiring before I would start by either reading up on the basics yourself or buying the time of someone who has.

You're not really looking for an 'in-line' resistor. That would just dim the bulb. I assume you are looking to add a resistor to fool the LCM so it doesn't trip a 'bad bulb' error message. Am I right? If so, you need to add resistance accross the +/- of the bulb. But if you do this on a bulb that's on for long periods of time, heat build up is going to be an issue. In that application you will need a relay to to drop the resistor out during use. Let me know exactly what you're trying to do and I will be able to better help you.

galacticos10 This is very easy to do. I've been through the experience with my 987 Boxster. You just need to connect the resistor across the two wires to the bulb. I need to do this is because the dash was continually displaying error messages because an 'apparent' fault was detected. Gator Bite has a better handle on this than me, but if I can help, PM me with an email address and I'll send you a diagram that shows how it works.

I've read (though never tried myself) that you can use thermal compound to attach the resistor to the frame of the car. That way the heat can be dissipated in the frame and you don't have to worry about wiring in a relay. That might be particularly useful for someone who doesn't have a lot of experience with wiring since a relay is going to be considerably more complicated than just splicing a resistor in parallel.

You are asking for trouble--resistor can get very hot.

The key issue is to make sure the resistor is not touching anything. Additionally you can make sure it's cooled by the air-flow at the front of the car anyway.

If they are indeed LEDs and have no built-in resistor you will need to add one in series to limit the current. Also, be aware these are polarity sensitive devices. No damage will result from connecting it backwards, it just won't work.

If you install a resistor across the lines of the LED Lamp, in order for it to work, the resistor would need to be about the same resistance as the original bulb when cold. That is a very low resistance resistor, and it will generate a LOT of heat. Another problem is finding a resistor that can handle that heat without melting. You will need a 10 watt resistor or better (which will become a heating element when the lights are on). If this is on a turn signal or reverse lamps, you may be able to get away with doing this because they are not on for very long. But if this is on parking lamps, you are asking for major trouble. You could burn your car down.

That's a really neat solution and galacticos10 I would suggest going for this. The LED sidelight bulbs on my 987 Boxster are currently using resistors that are simply across the bulb wires. I've made sure they cannot possibly touch anything but this solution is brilliant.

OK thanks a lot. I need to attach resistor as the LED would lit up dimly even when the light switch is not turned on.

My lights would extinguish after a short delay, but I needed to sort the errors anyway.

Wow. Thanks a lot for the reply. But it doesn't seem easy to install the resistor at all from what I saw in the pdf. It's too complicated for me I guess.

I'm sure it's not too complicated for you but I would always suggest that if you don't feel confident enough to do it yourself, give it to a professional. Unfortunately that always comes at a cost. The risk here (as Gator Bite pointed out) is that you could melt your car if the resistors make contact with something. I've made sure on my Boxster that I'm safe, but it was tricky finding the right location. That pdf is a really elegant solution and the one I would select if I did it again. In fact I may return to it at some stage to add the relay. Gator Bite What relay would you use?

http://superlumination.com/images/auto_bulbs/protector_wm.jpg LED Flashers Blinkers Resistors Load Equalizers for Turn Signal Replacement Bulbs Rapid Flashing Fix

Those nifty little resistors at the bottom of the page selling for $4.99 - $8.99 are sort of what we are talking about. But I have to point out that this is NOT the right way to do it. This is exactly what I was talking about earlier in the thread. These things will get HOT. This is a good solution because they have heat sinks. But keep in mind that this thing will get just as hot as a bulb would. Have you ever touched a bulb that's been on for a while? It will burn you instantly. Something else I would like to point out is that I would NEVER recommend the use of scotch locks (the blue connectors that come with these) on any automotive connections. Especially those that are exposed to moisture. They WILL corrode and eventually fail. They simply can not keep a good connection when exposed to the vibrations and moisture that are common in cars. I am speaking from experience. Many years ago, while working in a car audio installation department, one of our bosses got the bright idea that we would use T-taps and Scotch locks to make all of our connections on remote start and alarm installs from now on. We were going to save so much time that we would be able to do more cars. Great idea. Until about a year later when all of the cars we had done a year prior started coming back. We saw so many failures in that coming year that we implemented a policy that strictly prohibited the use of scotch locks and t-taps ever again. In this application, these connections will eventually fail. But they will fail slowly. First, they will build resistance at the connection point. When that happens, the connection point will become a heat point. This heat will melt the wire and destroy the copper for several inches in each direction of the connection point. The copper will turn black and become brittle. The insulation will melt, but it is unlikely it will expose the wire. Instead it will contribute to the decay of the copper. Eventually you will get a bulb warning (maybe 2 years or more) at which point the damage is done and you will need to replace the wire and/or bulb socket (if you connected close to it). Be warned. You can give these a try, but strip, twist and solder the connections. Throw those Scotch Locks in the trash where they belong.

Call Mike at Installation Distributors at [phone removed]. Tell him that you want either the DEI 8616 (mini relay assembly - $2.35) or the DEI 8617 (relay w/socket $3.50). Tell him that Mike S. sent you. You should do one for each side of the car. You will also need a low resistance 1/2 watt resistor. Id suggest Radio Shack. 6-10 ohms, 1/2 Watt (5 pack costs about $0.49).

I'll have to source the parts locally since I'm several thousand miles away in the UK. We don't have a Radio Shack but there are similar places. Thanks

If you can find the standard 30/40A SPDT automotive relay, or the Bosch 20/30A automotive relay, it will be marked on the bottom exactly the way I have shown in the PDF and you can be certain that your connections are spot on. That might be the way to go. At retail price, I would expect that relay to cost $10-$15 (in the USA). BTW - The Bosch brand relay is pretty much impervious to water. They are glued together. Many of the 'other' brands have a cover that snaps on and they are not waterproof.

UPDATE I have done some extensive testing and found that our LCM does in fact test the blubs when they are illuminated, so my prior relay suggestion will NOT satisfy the LCM. The only way to extinguish the warning is to install a full time resistor. A 10 Ohm 25 Watt will do the trick, but make sure it can breath because it's going to get very hot.