I have just recently did a fan swap from hydrolic fan to electric fan to cool my jeep gc 2001 4.7L limited. Everything works great besides the check engine light comes on. Thought I'd b able to bypass it but no luck. Has anyone done this fan swap n got there pcm ti work with it properly or figure out how to bypass it. Would love some help I can't pass emissions in my state with check engine light on even if it's not emissions related. My old fan set up is long gone n new one is like $900.00 please help someone....

 

You can try to disconnect the battery for about 15mins. Then hook it back up, start jeep and see if the light clears. But if it comes back. I would check for codes with a code scanner. If you don't have a code scanner.Go to O'reilly,PepBoys or any other Autoparts store. They will scan for free sometimes. Good luck

 

I ran code. It's saying cooling fan error. It can't communicate with my pcm. There's no plugs for it. I need a way to trick the pcm into thinking everything is working rite. Or make it work with it. Wish there was a kit of some sort. IV heard of people doing this but No one says anything bout the pcm light. Or how to bypass it.

 

The hydraulic fan is the most stupid and unnecessary design I've ever encountered in a jeep

 

I think it was some engineer's idea to reduce the load on the electrical system so they could put more electronic crap in without upgrading the alternator.

You've got to find out what the PCM is sensing, hydraulic fluid flow, whatever, and find some way to fool it. I'm sure some IT gurus could find out what to do.

Anything hydraulic tends to be pricey and prone to leaks. This might be okay for a bucket-loader or grader, but not for a car.

 

I hear they eliminated the clutch fan to increase horsepower... So stupid

 

Why not just run the electric fan the 4.0 uses? The 4.7 doesn't produce any more heat than the I6 does. You only gain about 2 hp without the clutch fan or about 5 hp without a direct engine driven fan.

However, the question is how to trick the PCM.