cooling fan wont turn on...

[jackmalone2001]

hello to all!

I have a weird one for you today!

My cooling fan on my 1994 3.4l Camaro wont turn on when the temp of the coolant rises.

I noticed that "hot engine" smell a week ago after normal in town driving, ambiant temp in the high 80's, and thought that my car was running much hotter than it normally does. Did not get an indication of high temp from the temp guage, but it seemed much hotter. Checked the coolant level, which was fine, but could hardly touch the hose cause it was so hot, but no cooling fan in operation. Assumed I had a bad temp sender and/or a bad fan motor too, so I replaced both. Now the temp guage is indicating a high temp condition but the fan wont come on. I can turn the fan on by turning on the AC, so I know the fan works, but I am stumped...

I checked the wiring diagram quickly and did not notice any other sensors, fuses, or relays.

Has anyone dealt with this kind of an issue?

As always any comments or guidence would be VERY much appreciated.

Thanks in advance, Jack

[Morley]

There is a relay that operates the fan, either the ECM isn't turning the relay on or it is bad/has bad wiring.

[jackmalone2001]

Thanks Morley,

How would I determine where the actual problem resides? Is there a way to find out if it's the BCM or wiring? I am not very versed in this so an in depth explanation/answer would be great!!!

Thanks again,

Jack

[ct91rs]

Start by replacing the relay morley suggested, its

UNDER HOOD, DRIVER SIDE, REAR ENGINE AREA, DRIVER SIDE OF MASTER CYLINDER, MOUNTED ON FIREWALL

Installing a new relay is much easier than tracing a wiring problem, hopefully that's it.

[CamaroRS92]

Question! Does the ECM control the fan relay on a 92 model camaro??
Im having a similar problem with the cooling fan not turning on upon temp. rise.
It will run with the A/C on - but not on its own .
I have replaced the relay & the sensor on the right hand side of the engine block.
I can force the fan to run by grounding the wire to this sensor, but it wont do it on its own.

Any suggestions

[jackmalone2001]

hey rs92,

I think it might have something to do with the computer telling the relay to open, then the fan will come on automatically. I continuity checked and replaced my relays to no avail, and now am thinking short in a wire or a computer problem. If you get any info please share, I will do the same! thanks!

[ct91rs]

I think that the switch sends a signal to the ecm, which then sends power to the relay, but I could be wrong.

Morley will know, hopefully he'll explain how it works.

[CamaroRS92]

I finally got the fan to run on Temp Rise on its own, by changing the type of switch in the engine block.
Im still not happy with the outcome though, because the fan does not start running until the temp gauge reads well over 220 degrees (almost in the red zone) so something is still not right.
I have eliminated the wiring, relay, motor,temp sensor on intake, temp switch on RH Engine block, & fuses.
What Next??? Could the ECM Be sending bad or wrong signal to the relay? How can the ECM be tested to find out if everything is working as it is supposed to (wondering if this could also be the cause of non stable idle RPM)

[Morley]

Originally Posted by CamaroRS92

I finally got the fan to run on Temp Rise on its own, by changing the type of switch in the engine block.
Im still not happy with the outcome though, because the fan does not start running until the temp gauge reads well over 220 degrees (almost in the red zone) so something is still not right.

220* is the correct temp for the fan to come on.

[CamaroRS92]

Originally Posted by Morley

220* is the correct temp for the fan to come on.

Morley,
Is there a lower temp switch available for this?
I would much rather it start cooling at a lower temp.
I am going by the temp gauge in the car and the fan doesn't start until way beyond the 220* mark (just in the edge of the red zone around 245* - 250*)

[Morley]

Originally Posted by CamaroRS92

Morley,
Is there a lower temp switch available for this?

Yes, Hypertec

[ct91rs]

http://www.hypertech.com/fanswitch.html

[CamaroRS92]

Thanks, Morley & ct91rs
Got it ordered!