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Dual fan hack question. Help!

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YOUR RESEARCHDual fan hack question. Help!

Leading reported evidence

Replace coolant reservoir

Performed · outcome unconfirmed

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Performed · outcome unconfirmed

Coolant reservoir was replaced a couple of years ago.

Dual fan hack question. Help!
Frequently discussed work

Check by a pro (if you are, pardon please)

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Suggestion

Before you go hacking the fans I would have the cooling system thoroughly checked by a pro (if you are, pardon please).

Dual fan hack question. Help!
Read full discussion summary

Leading evidence: 'Replace coolant reservoir' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'power resistors' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check by a pro (if you are, pardon please)' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.

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Compare 4 other evidence results

Replace fyi my water pump and thermostat

Performed · outcome unconfirmed

No successful repair reported for this finding.

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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed

FYI my water pump and thermostat was replaced about 30K/4 years ago when the IMS Solution was installed.

Dual fan hack question. Help!

power resistors

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Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that suspect a cause
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suspected cause

It's pretty likely the power resistors for your fans are damaged.

Dual fan hack question. Help!

Check by a pro (if you are, pardon please)

Suggestion or failed attempt

No successful repair reported for this finding.

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Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

Before you go hacking the fans I would have the cooling system thoroughly checked by a pro (if you are, pardon please).

Dual fan hack question. Help!

Replace with something cheaper; i

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

Here's a thread on replacing with something cheaper; I replaced mine with an OE part.

Dual fan hack question. Help!
Frequently discussed actions (8)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Check by a pro (if you are, pardon please)

No successful repair reported for this finding.

0
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0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

Before you go hacking the fans I would have the cooling system thoroughly checked by a pro (if you are, pardon please).

Dual fan hack question. Help!

Replace coolant reservoir

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed

Coolant reservoir was replaced a couple of years ago.

Dual fan hack question. Help!

Replace fyi my water pump and thermostat

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed

FYI my water pump and thermostat was replaced about 30K/4 years ago when the IMS Solution was installed.

Dual fan hack question. Help!

Replace with something cheaper; i

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

Here's a thread on replacing with something cheaper; I replaced mine with an OE part.

Dual fan hack question. Help!

Run cool --the stock gauge is garbage

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Suggestion

FYI for those who think they're running cool --The stock gauge is garbage.

Dual fan hack question. Help!

Run low speed and high speed

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Suggestion

The same fans run for both the low speed and high speed.

Dual fan hack question. Help!

Run occasionally while stopped

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Suggestion

Yes, my fans kick on while I’m driving and run occasionally while stopped.

Dual fan hack question. Help!

Run wire

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Suggestion · Original poster

I've looked at a couple how to's and know where the #20 and #22 relay's are, I just want to know how to run a wire to them while keeping the stock function of the fans turning on by themselves.

Dual fan hack question. Help!
Reported and suspected causes (1)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

power resistors

No successful repair reported for this finding.

0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Discussions that suspect a cause
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suspected cause

It's pretty likely the power resistors for your fans are damaged.

Dual fan hack question. Help!
Coverage and how to read this overview

Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.

33 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

  • Rennlist: 1 discussions

0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.

0 acknowledgements have no verified action link; they do not establish a repair result.

Generation: 20261027T035758Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Coming from a mostly mechanical background in wrenching I have almost no knowledge in wiring. That being said my coolant temps are hitting a hot 225F in stop and go traffic. After cleaning out the front rads, 160F thermostat, new water pump and switching to a new coolant reservoir cap I was hoping this would fix the problem at least a little bit, it didn't really do anything. Now I've come to the conclusion that I need to install a switch to control the fans since they have a mind of their own. I've looked at a couple how to's and know where the #20 and #22 relay's are, I just want to know how to run a wire to them while keeping the stock function of the fans turning on by themselves. Where do I connect this wire and HOW do I connect it. Pictures would be a god send... Help this noob out!

POST 2Original post

Before you go hacking the fans I would have the cooling system thoroughly checked by a pro (if you are, pardon please). I've been driving in 106 degree stop and go traffic and it never went over 190.

POST 3 / ORIGINAL POSTEROriginal post

Quotes source post: 15158835

Do you think there could still be air in the system? The bleeder seems to be working fine as it is raised when the engine is hot, I also switched out to a 997 reservoir cap just in case my 996 cap was faulty.

POST 4Original post

Quotes source post: 15158893

Where are you in Texas?

POST 5 / ORIGINAL POSTEROriginal post

Quotes source post: 15158905

Upstate NY, it's been a hot one this year.

POST 6Original post

100�+ down here in Houston and in 1 hours worth of stop and go traffic My temps are still at the leading edge of the 180� mark. You shouldn’t be getting that high! FYI my water pump and thermostat was replaced about 30K/4 years ago when the IMS Solution was installed. Coolant reservoir was replaced a couple of years ago. The rest is factory original.

POST 7Original post

As sasilverbullet said, you may want to have the coolant system checked, like him, I have been driving in 109 deg temp in stop and go traffic on the highway (mostly stopped) and my temp has never breached the 0 of the in 180 mark. I have the oem cap and thermostat.

POST 8 / ORIGINAL POSTEROriginal post

Quotes source post: 15158920

Are your radiator fans turning on at all? I think this is my problem. Mine don't turn on until 225F. This is why I'd love to turn them on manually at a much lower temp.

POST 9Original post

Yes, my fans kick on while I’m driving and run occasionally while stopped.

POST 10 / ORIGINAL POSTEROriginal post

Quotes source post: 15158942

Mine are only kicking in at 225F or if I turn the AC on.

POST 11Original post

Quotes source post: 15158946

Someone can chime in on which parts to fix (if this is the fan or a relay functions or something else). However there is a low speed and a high speed. I believe the low speed the fan turns on (not sure at what temp) and once it reaches 220 or 225 it kicks on both fans and go into high speed. Sounds like your low speed is not working. Edit: I found this https://www.renntech.org/forums/topi...-step-by-step/

POST 12 / ORIGINAL POSTEROriginal post

Quotes source post: 15158978

I've heard my low speed fans ever turn on only when I have AC on.

POST 14 / ORIGINAL POSTEROriginal post

Quotes source post: 15159149

Bad low fan relay?

POST 15Original post

Quotes source post: 15158813

How do you know it�s 225F? The last white line, well after the 180 on my car is only 206F. Have you measured with Durametric?

POST 16Original post

Quotes source post: 15159229

That would be my wild guess as I know someone that just went through this a couple of weeks ago.

POST 17 / ORIGINAL POSTEROriginal post

Quotes source post: 15159298

I have one of those eBay OBDII readers that tells me coolant temps and has a bunch of other features. It's a good buy for $7!!

POST 18Original post

FYI for those who think they're running cool --The stock gauge is garbage. The middle of '0' in 180 is actually about 210 per Durametric/OBD. Your purge valve should be manually actuated, i.e. it shouldn't be in the up position unless you moved the wire clip to set it there. The airlift tool is an awesome thing to have to refill your coolant and also to check that it is holding adequate pressure. Basic blocking and tackling: Make sure the coolant is full/bled and no more than a 50/50 mix. Verify the system is holding pressure. Validate the fan system is operating right. If it's only working on high it could be a bad low speed resistor. They're low to the ground and susceptible to damage and corrosion on these cars.

POST 19Original post

Quotes source post: 15158813

So pretty much nobody answered this. I've been looking to do the same thing. There have been 2 methods that I have seen... One - someone took the relay out with a piece of 18 gauge wire - stripped it and put it in the correct socket (85 if I remember - but definitely verify) and simply put the relay back in... this kind of wedged the wire in there. That's the ground side of the relay BTW. The other was to pull the relay holder out entirely and just tap into the wire from the bottom side. Honestly, I think I am just going to go the 'wedge it in there' route. I'll run the wires so there is no tension and no risk of it being pulled. Besides - if it comes out - it's just a ground jump. It just means that the switch won't work (but the automatic function stays the same)

POST 20Original post

Quotes source post: 15159386

Relays can easily be swapped to test... Sorry, resistor as bluchip mentioned is what I meant.

POST 21Original post

Quotes source post: 15159843

I agree it�s garbage, but mine is the other way around: Middle of 0 for my car is way under 200F. Such a shame we cannot rely on these gauges. What�s the point of them if they aren�t accurate? Are we just supposed to be happy if they are precise?

POST 22Original post

It's pretty likely the power resistors for your fans are damaged. The same fans run for both the low speed and high speed. A resistor is in series with the fan on the low speed setting, so the fan sees a lower voltage and spins slower. On the high speed setting, it sees the full 12V and spins full speed. If that resistor is blown on either fan, then it won't see ANY voltage on the low speed setting, and won't work until the car gets hot enough to trigger the high speed. This could be the issue that's letting your car get pretty hot before any fans come on; it may be trying to turn on the low speed, but the fan doesn't respond and the computer doesn't know that. The resistors are relatively exposed in front of the front wheels and can get splashed with water, exposed to hot and cold, etc. and have a tendency to fail. They're pretty easy to replace and it's been covered on here and other sites before. Before you go rewiring stuff and adding switches to trigger the fans on demand, I would fix the above to make sure all the baseline functions are working. If you have durametric you can trigger both low and high fan settings on demand to confirm what is working and what isn't. If you don't have that, you can jumper the relays to do the same test.

POST 23Original post

^^ Dumb question, but if the low speed fans come on when the OP turns on the AC, are those resistors being used in the same fashion?

POST 24Original post

Probably but the sound can be misleading. For instance on my car the passenger side resistor was burned, so without carefully checking, one might hear the driver's side fan running and think everything is fine, but they'd only be getting 1/2 the desired airflow.

POST 25Original post

Quotes source post: 15160443

Agree. You can feel the air even at low speed. High speed is REALLY obvious.

POST 26Original post

https://www.renntech.org/forums/topi...comment-179562 Might help

POST 27Original post

Quotes source post: 15160435

In a word, yes...same relay...same resistor(s). Not sure whether the logic upstream of the relay is software or electrical though

POST 28 / ORIGINAL POSTEROriginal post

Quotes source post: 15160472

Yeah, both my low speeds are working. Sometimes one is running and the other one isn't though? This has always confused me, it's done that ever since I bought it a year and a half ago. Does this still sound like a relay issue?

POST 29Original post

Yeah something is wrong then. Either shaky wiring, resistors, relays, or the fans themselves. The left and right fans should always be doing the same thing. There are no conditions when one should be running and the other is off, so you need to track down what's up with that first before monkeying with adding features.

POST 30 / ORIGINAL POSTEROriginal post

Where are these resistors located? Behind the wheel well cover? Or am I thinking of something else.

POST 31Original post

They are located in the outflow of the radiator cooling fans...metal cylinder with 3 wires....reach in and upwards from in front of your front wheels

POST 32Original post

Quotes source post: 15161388

They're in front of the front wheels; if you look up the hole in the bottom of the bumper where the fan exhaust comes out, you'll see them. Here's a thread on replacing with something cheaper; I replaced mine with an OE part. https://rennlist.com/forums/996-foru...placement.html

POST 33 / ORIGINAL POSTEROriginal post

Quotes source post: 15161420

Easy enough! Thanks so much

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