I have a 1998 Dodge Caravan with a 3.8 litre and the engine cooling fans are staying on all the time even after the key is removed and the engine has cooled off. I suspect the relay for the fans has gone bad which is OK after 230,000 miles.

I understand the fan relay is under the air filter box on the frame rail. Any tips on removing the old relay and detaching the wire connecting it?

I thought I would try this first and then if no success, try the sensor in the radiator and if that doesn't work, then I guess the PCM would be the last resort.

Is there any value in getting the fan relay from the dealer versus aftermarket. I know in some cases, it pays to get the OEM from the dealer and in some cases, not.

Any feedback or suggestions would be appreciated.

Jeff

 

Hi Jeff
I would use mopar parts, i have seen to many problems with aftermarket sensors. You can always disconnect the battery to stop the fan from draining the battery.

 

Thanks for the tips. I did undo the battery cable for the reason you mentioned or I would have a dead battery in less than an hour. Would you suggest starting with the fan relay before replacing the temperature sensor?

Thanks

Jeff

 

Hi Jeff
Yes i would. The relay is only held in with 2 5/16 or 8mm screws.The air cleaner box assy would have to come out to make the repairs.

 

As a quick first step here, you may want to disconnect the temperature sensor. If a shorted sensor is the problem, the fan should go off. I'm betting on the relay though.

 

disconnecting the temp sensor would be a waste of time. He says the fan is on at all times even with the key off. so at this point the sensor info to the pcm is off. the pcm commands the fan relay. so with the key off the PCM is "off" thus ending any command for relay on. I've seen a lot of these relay's fail either never working or stuck on at all times. You need a flat blade screwdriver, 10mm wrench and 8mm to remove it. They are spendy, I'd just go get a select good used one for replacement.

 

Just replaced the fan relay and that solved the problem. Thanks to everyone for your help.
Getting to the replay is pretty easy once you remove the air filter box and then it is just two 8 MM screws that attach it to the frame rail. The connector was a bit tricky to figure out how to release the relay but once that was done, I was home free.

Thanks again