I got a 1991 Z28 with a 305 TPI with two cooling fans. One cooling fan (not the A/C fan) useto always run. Now, it doesn't run at all. I have replaced the relay, the coolant temp sending unit, and even tried switching the power leads on the fans to see if the fan was toast; it wasn't. It ran fine. I have inspected the harness (as much as I can) and all looks fine. Buy the time the the aux fan kicks on, the temp is very high! No idea what to do. Any suggestions before I take it in and risk spending a lot of $?
Thanks.

 

I didnt see you mention a fuse anywhere.. checked them?

 

I checked the fuses and they are fine. Thanks for the reply!

 

Fan 1 doesnt work with factory 1 wiring.. fan 2 works with factory 2 wiring.. fan 1 works with factory 2 wiring.. does fan 2 work with fan 1 wiring? I'm willing to bet no.. which would mean your problem is in the fan 1 wiring somewhere.

 

I guess one of my only options would be to check the continuity of the wiring with a multi meter, from the fan back to the relay (if possible) and search for a break in the wiring.

Hey coop91rs, have you ever had any problems with excessive preasure in your fuel tank with your 91? This is going to be my next post.
Thanks for your help, it is appreciated!

 

You'd have to define excessive pressure. I'm assuming you mean when you remove the gas cap? You will hear the pressure release when you remove it. But neither of my 91's have anything I'd consider excessive. Just a short release of pressure and its all over.

 

When I talk about excessive preasure I mean that the tank will hiss for about 4 - 5 seconds when I take the cap off. If I put the cap back on and take it off 30 seconds later the same preasure will be built up and released. I posted the problem under the General engine section with the title "excessive preasure in fuel tank" if ya want to check it out. I figured I'd ask you since you have a 91 as well.

 

I had the same problem. I've got a 91 Z28 with the 350TPI, stock dual fan setup, and 180 t-stat. The pass side fan stopped working causing my car to overheat in traffic or at a stop. I could spin the fan freely with no resistance, so I figgured the motor was broken. I got a new fan motor from Napa for $30 something (jobber price) and replaced the fan motor. Now the car runs perfect, stays at 180 when the car is moving, and between 180 and 200 in stop/go traffic.

 

i am having a problem in the same area. but both of mine wont turn on. i have dont cont checks through every wire the haynes listed. all checked out. i habe replaced the both relays the fan switch and the temp sender. the fans ran when they were hooked up to a manual switch but now nothing. i also checked the fuse under the dash and the one by the battery. i am so any help. thanks
Bryce

 

I'm having the same problem also. I have a 89 IROC with the 350 and dual fan setup. I've replaced the fan relay by the battery, the temperature sensor above the starter, and the sensor on the front of the intake. I've tested the fan motors and they are ok, and the fuses are good too. The fans come on when I first crank up the car but after a minute or two they go off and don't come back on. Somebody please help me i'm about to run this car off of a bridge if I can't find out the problem

 

i perfectly understand. the thing that gets me is that my dash warning light does not come on when i start up and i have checked the light. so according to the book i have a open somewhere. but where? i have done continuity checks. i guess i will have to double check the wires. i know it isnt the fan motors,relays(next to the master cyclinder), the fan switch(passenger head) and the sending unit(driver head) i have checked the fuses under the dash and the fuse next to the battery. lucky for me right now wisconsin is cool so overheating is only if i am stuck in traffic.

 

Bryce,
You mentioned the fan switch and the sending unit. Could you explain exactly where these are located so I can check them? You had in brackets, "Passenger head and Drivers head" What did you mean by that?
Thanks a lot!

 

the fan switch is located by the passenger head between exhaust ports 6 and 8 and the sender is under the drivers head right out in the open. the sender is cheap but the fan switch i had to get from the dealer for $27.00
Bryce

 

CrazyHawaiian,

How did you remove the screw on the fan motor to remove the fan blades? I tried to remove that nut and it just keeps turning. I am missing something? Thanks for your help.

 

i have similar problem with my 350 TPI with dual fans

used to work just fine, now they dont work at all! manual switch dont work. FAn motors work when hot wire power to them, but dont turn on with the car or manual switch.

replaced relay and nothing! i have no clue what to do

 

I have the same problem with my fan, Can someone tell me where I could locate the relay and the Sending unit. I would really appreciate.

 

I have a 92 rs 305 car and it has single fan. I noticed a couple years back the fan quit working i jumped it straight to the battery and it ran. I put it on a toggle switch after i found the pigtail and wire to the sending unit were burnt replaced them hooked it back to factory style and it still wont come on. So i have it back on a toggle, I have put off trying to fix it back to stock but i have gottne cught up on some things and im in the process of trying to find my problem. It seems like gm flubbed up on this part of our cars.