88 cooling question
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,146
Likes: 9
From: Troy Ohio
88 cooling question
Hey guys any response would be helpful. Neither fan, the main or the auxiliary fan works on my car. I figured out the auxiliary problem, it was the sensor/switch on the left side of the motor was bad. Too bad I snapped it off in the block trying to take it out. AAAAGGGHHHH!!! Oh well, nothing a drill, and an easy out cant cure. ( I hope). Anyway on to the main fans. I have the GM manual and I have checked every circuit and cant find anything wrong. I even replaced the coolant temp sensor just to be sure. The only thing I think that is left is the ECM. But I would like to be sure before I shell out the money. I have no codes, the main fan comes on when I disconnect the A/C pressure switch, which tells me that at least the circuit out to the fan relay is ok. The problem is the manual does not seem to give me an internal schematic to the ECM, or any kind of logic layout. Does anyone know where I can find this? If anyone can see what I am missing here Please let me know. It drives me crazy when I cant figure out what should be a simple problem.
Oh well thanks for letting me vent, And thanks in advance for any responses.
Tom Snurr
35th anniversary :cry
Oh well thanks for letting me vent, And thanks in advance for any responses.
Tom Snurr
35th anniversary :cry
Instructor
Joined: Jun 2001
Posts: 129
Likes: 0
From: Oceanside N.Y.
Re: 88 cooling question (Tom 35th anniversary)
did you check the fan relay, located on drivers side wheel well. I have a page from haynes manual that I will upload when the home page starts working again 
you should be able to read this, sorry for the quality any question e-mail me
DAVE
[Modified by dt35th, 10:07 AM 3/1/2002]
[Modified by dt35th, 10:08 AM 3/1/2002]
[Modified by dt35th, 10:09 AM 3/1/2002]
[Modified by dt35th, 10:11 AM 3/1/2002]
you should be able to read this, sorry for the quality any question e-mail me
DAVE
[Modified by dt35th, 10:07 AM 3/1/2002]
[Modified by dt35th, 10:08 AM 3/1/2002]
[Modified by dt35th, 10:09 AM 3/1/2002]
[Modified by dt35th, 10:11 AM 3/1/2002]
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: 88 cooling question (Tom 35th anniversary)
The ECM turns on the main fan by grounding one terminal of the fan relay. I don't have my schematic with me at work and can't remember if the A/C pressure switch is connected to the relay or the ECM. If it is connected to the ECM, then the ECM is at fault by not being able to turn on the main fan , or, the temp sensor under the throttle body on the front of the block is not connected to the ECM therefore not telling the ECM what the coolant temp is which would also cause other problems that you would have mentioned.
Le Mans Master
Joined: Dec 1999
Posts: 8,540
Likes: 1
From: And on the fifth day, subpoenas were served to Obama senior staff
Re: 88 cooling question (Tom 35th anniversary)
Tom, you know that the main fan doesn't come on until over 220* or more, and the aux fan is higher still! If you have the shop manual, just go through the proceedure, I think in section 8 and you will find the fault (or just the temp!).
