nathan2003

I have a single electric cooling fan, and it keeps acting up. I just replaced the fan swith not to long ago with a 170* switch, I believe. I was just sittin there with my car running at idle while I'm getting the carb all adjusted and noticed the fan wasn't running at all so I jumped in the drivers seat and the temp was at 220 and I also had like my vent on. When I pushed the rod from vent to off and then back to vent the fan kicked on for a second but then died off so I put it on bi-level and the fan was running. Not sure if fan is suppose to run when you have it on vent but I swear it did before. Well anyways I pulled the rod back to see if the fan would just stay going but no luck on that. Whats the diagnosis for my cars sickness... I almost thinks its the fan switch but want some second opinions, I'm going to check the wires to the switch and make sure its all good tomorrow. Later guys.



Vetter

ede

which fan are you talking about, the cooling fan or blower motor fan? either i'm a little slow or you aren't real clear on it.

nathan2003

the cooling fan to my radiator.... the car will get up to 220 degrees and my fan won't kick on but when i turn on like bi-level that fan works......... so i have to drive with bi-level on otherwise the cooling fan won't turn on... that should clear it up a little bit...


Vetter

RB83L69

The stock fan switch turns the fan on at about 234°, and shuts the fan back off at about 210°. So 220° isn't warm enough yet to where the car is designed by the factory to recognize the need for cooling. It is a completely normal operating temperature for these cars.

If you put a 170° switch in the car, the fan should come on at 170°, and should essentially stay on 100% of the time.

In fact, if the car is sitting still idling, you should see the temp go up to about 235°; the fan should come on; the temp should go down to about 215°; the fan should shut off; the temp should begin to rise again; etc. etc. etc.

The reason the fan kicks on as you move the selector lever is because the fan is always on when the A/C is on. So any time the selector lever passes through the A/C or Defrost positions, the fan will come on. Bi-level is an A/C position, as clearly noted on the marking of the control head. Vent is not, and heat is not; but all other positions use the compressor.

If you can diconnect the wire from the fan switch (in the pass sisde head between the #6 & # plugs) and ground it and the fan comes on, then everything in the circuit besides the fan switch - the wiring, relay, connections, & fan motor - is working right. Maybe you don't have a 170° fan switch like you think you do.

Sounds to me like there's probably nothing at all wrong with your car.

nathan2003

hey, ya i understand the cooling stuff and temps but I do know I have a 170 switch. I ordered it from jegs 3 weeks ago and put it in and everything was working fine been working fine and I finally noticed that my car was gettin pretty warm and i couldn't hear the fan running... so i don't know what part of the fan system isn't working... so thats why i have it on bi level - so i have a fan running.... understand somewhat... i'm going to check my fan switch here right now..



Vetter

Vader

Where exactly on your engine is the "fan switch" located?

On a stock, single fan setup, the ECM controls the fan operation (as RB described) based on the Coolant Temperature Sensor input, not a switch. For a dual fan setup, the secondary fan is controlled by a switch mounted in the right cylinder head. The primary fan is still controlled by the ECM. Unless you reprogram the ECM or install a redundant temperature switch and circuit, the primary fan will continue to operate at stock temperature settings.

I installed a redundant switch in the water outlet:

88Camaro350

I hate to challenge Vader but the single fan setups also use the "fan switch" sensor in the passenger side cyclinder head. You can completely remove the ECU from a single fan car and the switch still kicks the fan on/off when its supposed to.

My fan was acting up also. It would not kick on unless I actually spun it alittle. Your may be doing the same thing.

Sometimes mine would work perfect sometimes it wouldn't. Turned out to be the motor. It would work but had trouble at first trying to turn.

I did away with my "fan switch" setup. I was running a mechanical fan but it sucked...so I reinstalled the electric fan and hard wired it. Now it always runs with the key. No more cooling problems

nathan2003

i'm sorry vader but mine does run off a switch... the sensor for the fan swithc is screwed into the passenger side of the block between the last 2 plugs like 88cam said... I do have an electric fan though right now and the fan only works when i'm running things off the compressor like bi-level and a/c... but if i have those off the switch won't kick it on sometimes... its a brand new switch like a month ago and it did work.... i think i kinda just figured out the problem right there... but i don't see how that switch is bad already... the other one had been in there since 1991 and i just put this one in... but it will kick on sometimes not always ... so i have a dilema... later




Vetter

Vader

Cool. My '86 doesn't have the redundant switch, so I wasn't sure about the '88s. They seem to be more like the earlier cars than the S/D cars in many respects, so I guess I got caught assuming again. I suppose the lack of a cold start is a hint at the other rewiring. I didn't have a choice with mine.