not getting much of a response to this on the electric board. Thought I should post it here.

Fan wasn't working when I bought the car, so I bought a new relay and put it into place. Fan comes on now as it should, but the temp gauge stopped working that day. It happened right after this, so I'm lead to believe that the wiring has something to do with the gauge not working. It does the check sweep when starting, and stays in place at the lowest point until the fan comes on, at which point the needle sweeps all the way to full hot until the fan is off again, then goes back down. I didn't think the fan relay had anything to do with the gauge, though. If it doesn't then it might be something else. I checked the sender wire and replaced the sensors. Seem to be fine. But the way it sweeps when the fan kicks on seems to point out that its something in the relay.


If the pic doesn't show it well enough, I can write out where I have connected wherever. I appreciate any help.

 

same thing with me except my fans dont come on. new relay but they wont come on. they come on if i jump it out. but i need to find out how to jump it out so they kick on as soon as i turn on the car.

 

why do you want it to be on when you start the car? the fan doesn't come on until 222 deg, I believe. you sure its not coming on instead of taking a long time?

By the way, I checked the sender again and saw that a wire wasn't connected all the way. I'll check it out in the morning, see if I fixed it. dont want to start it in a quiet neighborhood.

 

cause the car overheats. the fan wont turn on unless i flick the relay manualy then it sticks. that was the old relay.

 

Ok On Fuel injected cars it is really bad to leave the fan Run All the time.

1. Wear and Tear on fan Motor
2. Voltage Load on Charging and Electrical system.
3. If the car dosen't reach 180 degrees The ecm stays in open loop and your AFR will be off. I think It is 180 degrees, and I also think the car Will Be running rich. Someone Else will Correct me if i am not Totally Clear on this.

 

something like that.
anyway, I checked the sender wire again. How is that set up in the stock cars? is it just a wire going in to the sensor, or is there a male fitting for it? It looks as if mine is just strangely wired. I slipped the wire into the center of the sensor, tried the car again and the temp gauge still doesn't work. Anyone know what can be used to test the gauge?

 

turn the key on but do not start the car. Then take the wire from your temp guage an Ground it aginst the exhaust manifold or some where to make a good ground. If the guage is good it should peg the needle.

 

And if that grounding works, then your gauge is probably fine and you have managed to tie the temp gauge into the fan sensor wire.

I believe (not an expert on the fan operation - yet - but I'm working on it!) the way the fan switch works (which is on the head between cylinders #6 and #8) is that when it's inside it's "turn on the fan" temperature range all it does is provide a ground for the fans (via the relay). When the motor cools off below it's "turn it on" temp it removes the ground and the fans go off.

Since your gauge is reading essentially zero until the fans come on, coupled with the fact that it pegs out when they come on (just like when you ground the temp sensor's wire), implies the gauge is wired into the fan switch instead of the temp gauge sensor (or maybe both are tied together with your wiring splicing you did). The fan switch is on the passenger side on my 91 Firebird, and has a plug in type connector. The temp gauge sender is on the driver's side and has a "slide on from the side" type connector. Any chance you got these either reversed or tied together somehow?

Hope this helps a little bit. Have a Great Day!


- Vern

 

Just to avoid starting another thread....
Heres a pic of what I believe to be my fan control circuit(opened up to show problem).
1 is the unit casing.
2 is the reverse or back of the actual circuit board, specifically, a connection that is burnt out(if you couldnt already tell!)
3 is one of the wires which comes from the unit, which for some reason has been cut(not by me!)

Heres the problem:
my fan NEVER goes on, so I opened the unit pictured and noticed the problems labled by numbers 2 & 3, and came to the gloriously devine revelation.....ok, the conclusion....that my fan stopped running either due to the circuit in number 2 burning out, and/or the wire in number 3 being cut.

Heres what DOES work:
theres a small door-bell type copper wire-spool with two metal connector pins. When I press them together, the fan DOES turn on by means of the red wire seen behind numbers 2&3 until I release them from touching.

HEEEELLLLP! I got a SPSD(whatever it's called) switch and I'm considering wiring it to the red wire and then the thermo. and mounting it in my car.
-G