and I have replaced the radiator fan relay... with no change. What should I look at next? Rather annoying having to consistently remove the fuse in order to keep the battery from draining.

 

Are you sure it only has one relay for the fan? It’s common for there to be a low speed and high speed relay.

Post the year and engine size and I can advise you further once I get a look at a wiring diagram.

 

It is a 2005 Dodge Grand Caravan with a 3.8L V6 engine.

 

Is the check engine light on or have you tried to pull any codes? Also will the fans shut off if you pull the relay and leave the fuse?

It’s a pretty straight forward control circuit- the coolant temp sensor receives power and ground from the PCM - once the PCM sees the temp is high enough, it turns on the fan(s) via the IPM and relay.

Try unplugging the engine coolant temp sensor instead of pulling the fuse. If that shuts off the fans, the sensor needs to be replaced. If not, remove the relay, hook a test light to B- and probe pin 4 (Dark Blue/Violet wire). If the test light is on (especially with the engine cold), either the PCM is commanding the relay on for some reason or there’s a short to voltage on that wire between the relay and PCM.

 

Thank you... Is the engine coolant temp sensor back right of the engine block below the spark plugs?

 

If you’re standing at the front of the van and looking at the engine, the right rear is correct, but I don’t think it’s below the spark plugs.

#1 is the ECT and #3 is a heater hose fitting.

 

It is behind and below the coil pack.