I have a 2000 Dodge Dakota With the 4.7 in it fans worked fine then all the sudden driving down the road noticed it started to get hot. Pulling hills it will over heat. I looked into it I noticed the electric fan was not turning on. I checked relay it was fine. I check voltage in the fuse box it was fine. I jumped the fan wires fan started right up. So I jumped the relay in pin 87 and I believe its pin 30 but don't remember and the fan started right up. So then I read on a forum where if I pulled the wires off the temp sensor if the fan started then it was not my PCM it started right up when I pulled the wires off. I am really stumped and not sure where else to turn to try to get it to turn on when it gets hot. It also will not turn on when I have the AC on. But everything seems to test fine I took the relay out of the starter and put it in the fan relay and still nothing put the old fan relay in the started relay the truck started so I know its not the relay. I checked the 40 AMP maxi fuse and it seems fine. I am just not sure where else to check please any help would be awesome!!!!!

 

There are two fuses a30 amp in the power distribution center should be number 2 prob a maxi. And a10 amp in the junction block should be number 9. Hope that helps

 

But if it was a fuse wouldn't the fan not work when I unplugged the temp sensor?

 

That's true. How is your ect sensor? Maybe that's not working? Maybe pcm isn't getting signal from it. But then the gauge wouldn't work either. Do you have access to a scan tool? Can you command it on?

 

I have a scan tool but does not have the option to turn the fan on. I beleive it's good thinking about changing it. The only reason I haven't messed with it yet is because the fan won't turn on with A/C either but half tempted to change it anyways.

 

And I was lead to beleive if you unplug your ect sensor and the fan comes on then that's one way of testing the pcm cause when you unplug the ect the pcm fixed into a safe mode and turns the fan on full time and mine turns on when I unplug the ect sensor so I thought that the pcm was doing its job

 

I can't say I've heard that. But it worked. All I'm saying is maybe the Ect is not sending out a signal.

 

Okay well I am going to give it a shot saturday then and I will let you know. I appreciate your help. I had never heard the unplugging from ect to test before but one of my buddies says thats how his dad did his and his dad is a mechanic at a dodge dealership he is going to take a look saturday to so I will definetly let you know the outcome of the ect replacement and everything. Hopefully it gets fixed or I will be back here asking for more help haha

 

Do you remember how you fixed this problem?

 

You already have your own thread going on this issue. No need to bump a 6 year old post.