cooling fans, CTS, and temp gauge ain't doing there jobs
06-02-2007, 07:00 PM
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cooling fans, CTS, and temp gauge ain't doing there jobs
Trying to diagnose a problem on the 95. Cooling fans don't come on and car runs very hot. This is a common problem and I've done the searches. I could trick the PCM like Willwren suggests, but I want some more info about this situation first.
1. The dash gauge acts funny. Goes up and down like a see-saw sometimes. Don't ask me how accurate it is. 95 scan problems and all that. Does the interior gauge even
matter?? It'* not actually part of the fan cooling process, is it?
2. Both interior and firewall cooling fan fuses are OK.
3. The relays are probably fine because both fans went out completely and there is a separate relay for low and high so I doubt if they both took a vacation together.
4. CTSs are original I think. I believe there are two?? One is under throttle body but I don't know about the other. Could they be telling the PCM some bogus info so it doesn't turn on the fans?
5. Oh yeah. AC will not make fans run either, and I tested the fan motors.
6. Basically, before I rig up a PCM ground override switch for the fans, is there another component I should change because maybe the PCM really doesn't know it should be turning on the fans?
1. The dash gauge acts funny. Goes up and down like a see-saw sometimes. Don't ask me how accurate it is. 95 scan problems and all that. Does the interior gauge even
matter?? It'* not actually part of the fan cooling process, is it?
2. Both interior and firewall cooling fan fuses are OK.
3. The relays are probably fine because both fans went out completely and there is a separate relay for low and high so I doubt if they both took a vacation together.
4. CTSs are original I think. I believe there are two?? One is under throttle body but I don't know about the other. Could they be telling the PCM some bogus info so it doesn't turn on the fans?
5. Oh yeah. AC will not make fans run either, and I tested the fan motors.
6. Basically, before I rig up a PCM ground override switch for the fans, is there another component I should change because maybe the PCM really doesn't know it should be turning on the fans?
06-02-2007, 07:12 PM
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You need to get a tool on that car to see what the PCM is seeing and what its doing at that time...
when you turn on the AC, you will be able to watch the PCM request the fans on..
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when you turn on the AC, you will be able to watch the PCM request the fans on..
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06-02-2007, 08:44 PM
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Easier said than done. The part stores can't read a 95, so that means paying a shop.
Anyway, "IF" the PCM is requesting the fans on, then what else would be keeping both of them from running at all. Both don't run either low or high. That rules out alot of wire and relay possibilities unless there is a big coincidence with both fans. Is there another single component other than the PCM that gets these fans running?
Anyway, "IF" the PCM is requesting the fans on, then what else would be keeping both of them from running at all. Both don't run either low or high. That rules out alot of wire and relay possibilities unless there is a big coincidence with both fans. Is there another single component other than the PCM that gets these fans running?
06-03-2007, 04:06 PM
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At the right temperature say 220-227F the PCM should turn the fans on Via the Relays... Both fans will run at the same time, either in low speed or high speed.. Same goes for the AC being on, The PCM will look for the head pressure, and when it come up as you have turned the AC on the PCM will then command the fans on, Usually low speed first followed by High speed..
Maymybonnieliveforevr had a similar issue.... After putting the tool on it I found the PCM was not a happy camper... But he was able to drive from Brampton( spelling ?? ) to Enfield CT with no real trouble...
We found that at 180F the PCM was still stuck in Closed loop.... That was a big issue on its own.. Among several ghost codes....
Its possible that you could be having PCM issues as well but I don't want to see you with a part you don't need.. But having a Spare is worth it..
As far as we can tell the 94-95 PCM'* are really bad in the failure department... Worse than any 87-99 Bonneville I have ever seen... I am on #3 in my 95... It was a Low milage unit too which is a good thing for me as I do not trust the 94-95 PCM as far as I could throw one... I make trips with a designated Trunk PCM...lol
Wish I was there to be able to give you a hand..
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Maymybonnieliveforevr had a similar issue.... After putting the tool on it I found the PCM was not a happy camper... But he was able to drive from Brampton( spelling ?? ) to Enfield CT with no real trouble...
We found that at 180F the PCM was still stuck in Closed loop.... That was a big issue on its own.. Among several ghost codes....
Its possible that you could be having PCM issues as well but I don't want to see you with a part you don't need.. But having a Spare is worth it..
As far as we can tell the 94-95 PCM'* are really bad in the failure department... Worse than any 87-99 Bonneville I have ever seen... I am on #3 in my 95... It was a Low milage unit too which is a good thing for me as I do not trust the 94-95 PCM as far as I could throw one... I make trips with a designated Trunk PCM...lol
Wish I was there to be able to give you a hand..
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06-03-2007, 05:26 PM
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Well I have had a lot of issues with ghost codes. I took it to a shop over the winter because the SES light and volt light came on. The shop said I had a ton of codes and wanted to change the PCM. I told them OK but I wasn't paying for the PCM if it didn't fix the problems, and they couldn't return it to the parts house, so they better be sure. Long story short, it didn't change anything and the lights are still on. They put my old PCM back in. Maybe the fans haven't been working since the winter also. After their incorrect diagnosis the shop didn't really want to work on it anymore, and kept making excuses. So I just put up with the dash lights cause it'* not worth paying these shops to guess at it. But now I can't even drive it because of the heat. 
06-03-2007, 05:35 PM
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Do you by chance remember what codes you had?
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06-03-2007, 11:30 PM
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No, the shop was being very vague about them. One was MAP, and another was ....
darn I can't remember. It was quite a few. There was a quad failure that made them want to change the PCM. The jerk at the shop kept clearing them before he would tell them to me. I would ask for all the codes and he would say "I reset the computer, go drive it and see if it happens again." It'* hard to get past the service writer to talk to the mechanics. I know this is impossible to diagnose over the net without the car being scanned. I appreciate the efforts. I was hoping someone had this exact problem and there was a "been-there-done-that" solution.
darn I can't remember. It was quite a few. There was a quad failure that made them want to change the PCM. The jerk at the shop kept clearing them before he would tell them to me. I would ask for all the codes and he would say "I reset the computer, go drive it and see if it happens again." It'* hard to get past the service writer to talk to the mechanics. I know this is impossible to diagnose over the net without the car being scanned. I appreciate the efforts. I was hoping someone had this exact problem and there was a "been-there-done-that" solution.
06-04-2007, 08:17 AM
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He'* not really trying to be a jerk.. the first procedure in the FSM is clear codes and see fi they return immediately.
Honestly..with a 94/95 I would strongly recommend getting a scan tool on it that will read live parameters. W/o this..you have no idea how far off or on the mark your gauge is. It'* like shooting in the dark at a mosquito.
Honestly..with a 94/95 I would strongly recommend getting a scan tool on it that will read live parameters. W/o this..you have no idea how far off or on the mark your gauge is. It'* like shooting in the dark at a mosquito.
06-04-2007, 04:00 PM
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Bill, I know, but the guy cleared them once, then tried a new PCM, then put the old one back and cleared them again. When I asked them what the were he said he had cleared them. At this point he had read them three times, but couldn't remember them all or didn't write any of them down, and didn't want to talk about them. It was apparent to me they didn't want to bother with a big diagnosis issue. Bunch of parts-changers is all they are, not real technicians. It'* hard to find a good shop.
Anyway, I'm going to ground the PCM wire for the fans in the next few minutes to see if they work (as instructed by one of willwren'* posts). If they do, I know the PCM is screwing up or missinformed about the temp. If they don't, I'll be back posting some more questions.
Anyway, I'm going to ground the PCM wire for the fans in the next few minutes to see if they work (as instructed by one of willwren'* posts). If they do, I know the PCM is screwing up or missinformed about the temp. If they don't, I'll be back posting some more questions.
06-04-2007, 04:39 PM
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My experience with your year tells me there'* a 70% chance your gauge is inaccurate and the temps aren't high enough for the fans to come on. A 20% chance your pcm needs to be swapped out and a 10% chance you have a bad connection at the relays.
By grounding that wire.. you will know if the relay is bad or good. That will eliminate one item. Unfortunately..the two that need a scanner are left to question.
By grounding that wire.. you will know if the relay is bad or good. That will eliminate one item. Unfortunately..the two that need a scanner are left to question.