My electric fan on my 89 Firebird TBI has been coming on and going off at odd time intervals. I have replaced the following items to no avail:

The Radiator Cap
The Coolant Temperature Sensor
The Thermostat

What should I look at next as the most probable cause of my problem? I'm not good with electronics, and I have no clue where any relay switches or things like that are located.

Thanks for the help.

 

'odd time intervals'?

You've just got the single fan set up right? Your fan should come on whenever your coolant reaches the 220-230 range at the location your sensor is.. Note that could be different than what your guage reads because of gauge inaccuracy and the fact that (I believe) there's a coolant temp sender for the gauge and a coolant temp sensor for your fan. Buy a Haynes or a Chiltons... that'll lead you in the right direction.

Anyway, if your fan is coming on at the right temp, that's more important than the right time...

Let me know if you're having a different problem than what I see..

james

 

dps8315,

My fan comes on at odd temperatures as well. For example, it'll come on when I start the car cold....then stay on until the engine reaches say 190, then it will shut off for 5 minutes, then come on again when the temp is near 220. Sometimes it just stays on constantly, no matter what the temperature is. Any suggestions?

 

Anyone got any ideas???

 

Anyone?

 

Sounds like you have a demon..............I'll do some diggin and see what I can come up with...........but for now you might try some HOLY WATER...........lol

 

idrag2,

Thanks. Yeah, I thought when I replaced the coolant temperature sensor, my problems would be over, but they weren't

 

when the fan comes on with the motor cold do you have the defroster or A/C on also, the fan runs any time you are using either one of these even if the fan switch is bad. the fan switch is located on the passenger side of the motor between #6 and #8 spark plugs (it has a single wire going to it), there is also a sender for your gauge located elsewhere on the engine

 

It could be an intermittent ground in the fan control wiring (to the sensor), arcing and carbon of the relay contacts, or an intermittent connection with the AC high pressure cutout switch. Any of these could cause the fan to operate without the temperature switch being closed.

 

1986 Redbird,
This fan switch you speak of between #8 and # 6 sparkplugs, do you think replacing it will most likely solve the fan problem?

Vader,
I would tend not to think it is a problem with intermitent connections, since in the last couple of days, the fan has been on constantly, no matter what the engine temp. The arcing and carboning of the relay contacts seems more likely. Perhaps I will replace these. Is this the same as the fan switch 1986 Redbird was talking about?

 

the fan switch they speak of is, as previously metioned, located on the passenger side head by #6 & #8 Plugs.


this is what it should look something like this while looking from underneath...........

 

If the fan is now running constantly, you may have a grounded fan control wire at or near the temperature switch, or the AC pressure switch may be disconnected of failed.

 

Would you be so kind as to tell me where the AC pressure switch is located? Thanks.

 

I'm assuming this is TPI. Which coolant temperature sensor did you replace. There's two of them! One goes to your guage and only your guage. It has one wire connected to it and it is located between cylinders 1 & 3. The second one is on the very fron of the TPI, going into a water jacket and has a plug going into it. The second one is what the computer uses to do stuff. Check it out!

 

BenDoe91z28,

My car is a TBI.

UPDATE: When I turn on my ignition (not to start the car, but just to turn the power on), I hear a loud click and then my fan goes on. This is without the darn engine even running.

Does this mean it is likely that a grounded wire somewhere is the problem?