Hey people I need help. My ac started going out little by little when drivinging. If I am in park or at a stop light it will cool a little bit, but once I start moving it stops all together. Also, the fan wont come on all the time on its own. Sometimes I have to hit the top of the fuse box to get the clutch to engage and the fans return on.

 

My first thought was the coolant temperature sensor being defective but if you have to bang on the fuse box to get the fan to come on, it sounds like a bad connection involving the fan relay or the AC relay. When you turn on the air-conditioning, a request is sent to the ECM to turn on the fan under the hood and also to energize the AC compressor clutch to engage with the compressor.

I am guessing that the ECM is programmed such that if the fans will not turn on, then the AC will not kick in. It must be monitoring the V drop across the fan to determine whether the circuit is open or closed.. So I will guess fan relay bad connection either in the sockets above where the relay plugs in or underneath the fuse box with the wires running to and from those contacts slots.

You may be able to solve this issue. Remove and reinsert the fan relay using no more than normal force. Do this about 30 times. There is likely a layer of corrosion buildup on the relay contacts or inside the slots into which they plug in. Repeated removal reinsertion sweeps the corrosion off of the connectors that need to have good electrical contact.

Do this with the fan relay only at first. See if it corrects the issue. normal impulse would be to do the same with the AC relay at the same time. The only issue with that is that by changing two things at once you will not know what solved your problem should it occur again.

So do the fan relay first. Evaluate. Then the AC relay..

There is a possibility that the coolant temperature sensor is defective but until we are sure that the connections at the relay, the fuse box, and the wiring leading to the fan are solid, we can't tell.

Performing the process of elimination in the most logical order lets you pinpoint the root cause so if it happens again you can solve it in under a minute.

Please come back and let us know how it works out or if you require additional help.

 

Thanks for the quick reply. I have swapped relays and fuses but have not inserted and removed 30 or more times to get rid of corrosion. I will try first thing tomorrow.

 

Ok so i worked on the fuses and I've gotten the fan to stay on when the compressor kicks on and both stay on. Freon level looks good, but it will only cool while at idle. Once I start driving it stops cooling. And when I say cool and cooling, it's not cold like it used to be. Before the issue it was really cold air at idle or driving. Now it's just cool at idle and hot while driving. Wondering if it could be a pressure switch or if the compressor has just gone bad. Ps l, the other day when I started the car the compressor was squealing and shot out what I thought was smoke or freon? The problem stayed the same after that gappen