Hi all,
I have a 2002 Dodge Ram 1500 with 5.9L, and I am having an issue which even has a mechanic scratching his head. Recently replaced AC compressor, orffice tube, and dryer. Fresh charge and you would think I was ready for summer. Here's where it gets tricky. I was getting nothing but warm air and that was because the AC condensor fan was not kicking in and apon further investigation, I found theplug had been cut off and taped off. So, I put a new plug on and whammo, works. But when I turn the truck off the fan doesn't, ever.I replaced the relay with a new one but I have to pull the relay for the fan to shut it off. Any ideas? I was thinking off running a toggle switch into the cab if need be, but I'd rather not. Anybody have or heard of the same problem? Any help or ideas would be great.
Thanks

 

well since someone cut off and taped the connector, maybe they did something else to it. Are you the second owner? There has to be a reason someone cut off and taped that connector. There could be a short in the line somewhere that controls the fan, although it should still shut off when the vehicle is turned off. Do you know if the vehicle was ever in an accident?

 

Yes, I am the second owner, and as far as accidents, no, there has been none..

 

Atleast thats what the Carfax report said.

 

I would recommend trying to get ahold of a repair manual (Chilton/Haynes or the like) and look at the schematics. If you pull the relay and it shuts off the fan, then something is tripping that relay (do you hear it click as soon as you plut it in?). It could be a short on a wiring harness, or the previous owner may have done something that messed it up. Obviously he knew something was wrong and his solution was to disconnect the fan.I suspect that it is something on the control end of the circuit as opposed to the wires that lead from the relay to the fan.

 

I just thought of another thing... Anyone know if there is a thermostat that controls that fan that may be broken and keeping the relay tripped?

 

Does it use a high pressure switch in the high side refrigerant line? I would think that it should still lose power with the key off unles the relay is just stuck shut.

 

I have replaced the relay, so I don't think it is stuck open. My mechanic put a 4 prong relay in the slot and this is what happened. When I turn the truck off, the fan shuts off for about 2 seconds and then kicks back in, so I will pull the relay and then put it back in and the fan doesn't start back up. But when I go to put the 5 prong relay in, the fan starts no matter what. Whether the truck is on or not.

 

Try probing the relay socket with a multimeter. Determine which side is the coil and see if you are getting 12v across those contacts. If so, then you know that something is tripping that relay. Try that with the key both on and off. If the voltage remains the same, then you know it's something on the controlling end and not the relay or wiring to the fan. At that point, you have divided your problem area in half and can work from there... You will need to determine WHY you are always getting 12v to that relay. It could be another relay that is bad... Does anything else stay on when you shut off the truck? This is why a set of schematics would help you out. You can see everything that is in that circuit that might be applying power to the circuit.

 

Took it to the dealership today. They are telling me I need a new PCM...There is a short.