cooling fans, CTS, and temp gauge ain't doing there jobs - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 06-02-2007, 08:00 PM   #1
Senior Member
Posts like a Supercharger
Thread Starter
 
Join Date: Jan 2007
Location: Missouri
Posts: 186
Thanks: 0
Thanked 0 Times in 0 Posts
skregal is on a distinguished road
Default 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?
skregal is offline   Reply With Quote
Old 06-02-2007, 08:12 PM   #2
BANNED
 
Join Date: Aug 2002
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
banned3800 is on a distinguished road
Default

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..

__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
banned3800 is offline   Reply With Quote
Old 06-02-2007, 09:44 PM   #3
Senior Member
Posts like a Supercharger
Thread Starter
 
Join Date: Jan 2007
Location: Missouri
Posts: 186
Thanks: 0
Thanked 0 Times in 0 Posts
skregal is on a distinguished road
Default

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?
skregal is offline   Reply With Quote
Old 06-03-2007, 05:06 PM   #4
BANNED
 
Join Date: Aug 2002
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
banned3800 is on a distinguished road
Default

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..

__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
banned3800 is offline   Reply With Quote
Old 06-03-2007, 06:26 PM   #5
Senior Member
Posts like a Supercharger
Thread Starter
 
Join Date: Jan 2007
Location: Missouri
Posts: 186
Thanks: 0
Thanked 0 Times in 0 Posts
skregal is on a distinguished road
Default

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.
skregal is offline   Reply With Quote
Old 06-03-2007, 06:35 PM   #6
BANNED
 
Join Date: Aug 2002
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
banned3800 is on a distinguished road
Default

Do you by chance remember what codes you had?

__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
banned3800 is offline   Reply With Quote
Old 06-04-2007, 12:30 AM   #7
Senior Member
Posts like a Supercharger
Thread Starter
 
Join Date: Jan 2007
Location: Missouri
Posts: 186
Thanks: 0
Thanked 0 Times in 0 Posts
skregal is on a distinguished road
Default

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.
skregal is offline   Reply With Quote
Old 06-04-2007, 09:17 AM   #8
DINOSAURUS BOOSTUS

Expert Gearhead
 
BillBoost37's Avatar
 
Join Date: Mar 2005
Location: Enfield, CT
Posts: 41,391
Thanks: 0
Thanked 0 Times in 0 Posts
BillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of light
Default

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.
BillBoost37 is offline   Reply With Quote
Old 06-04-2007, 05:00 PM   #9
Senior Member
Posts like a Supercharger
Thread Starter
 
Join Date: Jan 2007
Location: Missouri
Posts: 186
Thanks: 0
Thanked 0 Times in 0 Posts
skregal is on a distinguished road
Default

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.
skregal is offline   Reply With Quote
Old 06-04-2007, 05:39 PM   #10
DINOSAURUS BOOSTUS

Expert Gearhead
 
BillBoost37's Avatar
 
Join Date: Mar 2005
Location: Enfield, CT
Posts: 41,391
Thanks: 0
Thanked 0 Times in 0 Posts
BillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of light
Default

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.
BillBoost37 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Gm ain't doing the right thing. jerrythepainter Introductions for new members 3 08-20-2012 10:31 AM
cooling fans and A/C Bonnevillan 1992-1999 5 03-26-2008 10:32 AM
No Cooling Fans and AC not Cycling coopsse 1992-1999 6 01-12-2007 01:14 PM
There are worse jobs out there... MOS95B Lounge 2 06-20-2006 10:37 AM
A/C and cooling fans quit simultaneously... TrueWildMan 1992-1999 11 06-23-2004 10:11 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 03:18 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.