[HeavyBall]

I have a '91 LS, and am having a strange problem with overheating. After driving for about 20 minutes in slow-moving traffic, the temp starts to move up. When I accelerate, it begins to drop back down to normal. I've noticed that only one fan comes on, even when overheating, but both fan motors are good (tested with battery).

A mechanic at a dealership told me that when I turn on the A/C, both fans should come on, but neither does. All fuses are good. I assume it can't be the thermostat, because it doesn't completely overheat.

Does the temperature gauge read from the radiator sensor or the motor sensor?

I thought about replacing the relay(s), but don't know which to replace.

Anyone have any thoughts?

 

[HeavyBall]

Thanks for the replies.

The problem is that I don't know which relays I should be looking at. There are two relay boxes by the battery, one is long and rectangular, the other smaller and square (According to the Chilton manual, I'm looking for Box A). There is also a Relay box near the firewall on the passenger side.

I've found a few threads referring to the location of the relays using search, but the threads have been deleted.

Any ideas which relays I'm looking for?

Also, do I get them from the dealership or will aftermarket work?

Thanks again.

 

[HeavyBall]

Thanks JetDoc!

That's exactly what I needed. I am going to test right now.

I have a Chilton, but the relay location descriptions are vague at best.

 

[HeavyBall]

I just switched the relays -- the fans still don't come on with the A/C on.

Considering the up and down idleing and white smoke, I don't think it matters much (BHG). I would, however, like to get as many miles as possible out of the car.

Anything else electrical I could check to get the fans working with the A/C?

Thanks!

 

[HeavyBall]

Sure enough, I pulled the condensor fan relay and saw that it was blown. Replaced it with the horn relay and the fans came on as soon as I turned on the A/C. Didn't realize that the condensor fan relay would affect the two radiator fans.

On a side note, any recommendations on dealing with a BHG other than maintaining coolant and oil levels?

Thanks again! You've been a great help.