98 Century Cooling fans not working?

I did a search but didn't find any help. My brother has a 98 century 3.1lt. Engine is overheating. When I did an inspection I found that the cooling fans would not come on. They will come on when AC set to max. Temp gauge is working. Any suggestions? Which relay controls fans during normal operation?

As a stop gap I told him to leave his AC set on MAX.

George

You should have two cooling fan relays pass side front of engine compartment. Relay no. 1 should be the relay. For a quick test try switching relays. Also if swapping relays don't work check engine temp. sensor. this should be close to upper radiator hose and intake.

You should have two cooling fan relays pass side front of engine compartment. Relay no. 1 should be the relay. For a quick test try switching relays. Also if swapping relays don't work check engine temp. sensor. this should be close to upper radiator hose and intake.

I disagree. If the coolings fans come on with the A/C there is nothing wrong with any of the cooling fan relays. It sounds more like a PCM module or engine coolant temperature sensor (ECT) related problem.

How was it determined the engine is overheating? The coolings fans will not turn on in low speed until 220 degrees F and high speed at 230 degrees F.

With engine off disconnect the ECT sensor. Then start engine with A/C off. Both cooling fans should turn on in hi-speed in less than 5 seconds. Simple troubleshooting procedure to determine what direction to head.

Thanks for the replys.

I tried switching relays, that didn't help. As to overheating, my brother stated that it overheated when he came to a stop and sat in traffic, temp gauge would rise and steam would appear. I didn't have long to play with it. I started it and let it idle and the temp gauge continued to rise past normal. I then turned on AC and temps returned to normal. I will have him check the ect.

George