no power to fan,compressor high reading
 

I recently changed both relay switches for the high and low fan. also I changed the one for the HVAC relay as well, still I have no power to the cooling fan. I unplugged the wires from the fan to see if I ran a straight jumper wire to it if it would start and it did, but it was kinda noisy and the wires got hot to touch really quick. Also I used my test light to see if I was getting power to fan and I was not, even the temperature was above the half way mark. also, the compressor kicks on when you first start the engine, but then shuts off and blows warm air into the cab. I put one of those gauges that comes with the can of Freon and it read way high, like 125. I cant figure this crazy problem out , I looked in both the fuse boxes under the hood and couldn't find a blown fuse, also I checked the one under dash. is there something im missing?? maybe an A/C switch,or Compressor control relay or something? if so, WHERE DO I LOOK FOR THEM ON MY JEEP? im stressin . Anyone that can help it would be GREATLY appreciated. THANK YOU
BTW... ITS A 2006 Grand Cherokee Limited 4.7 litre... and its my wifes jeep.... who cant stand having no A/C.

1. The fan "relay" or controller might be bad. I had that happen on my 99, but I am not familiar with the later models. Not sure which came first, but it was eating fan motors. You might have the "combo deal" like I did.

2. The freon pressure is going to be high when the compressor is not running, as it will equalize throughout the system while at rest. Normally, the fan comes on incidental to the compressor as the A/C will dump a bunch of heat in front of the radiator.

ETA: apparently there are two relays in the under hood power distribution box, and are both controlled by the 50a fuse. Check those out and see if you can get it to fire up.

If it is like my 99, there is some witchcraft involved with that motor. It is variable speed and doesn't behave like we normally expect. Driving it with a switched 12v supply is not advised. I do know that replacing the controller fixed mine. Probably metric electrons in a square wave AC pattern or some nonsense that the Germans came up with to shoehorn a clock into a windchime.

Okay, on the '99-'04 4.0s, there is a "pulse modulated" relay for the fan mounted on the frame underneath the right headlight plastic mounting panel. It is sent a pulsed DC signal by the PCM to control it's speed. It's a PITA to get to to replace, but it is inexpensive. There is only 1 40 amp fuse. I'm told the reason it's mounted there is for heat dissipation.

The 4.7 with the hydraulic fan is not in my list of information, but I'm told the system is similar.

The 2006 IDK about.

Almost got it.... I think.
 

Ok, so I found that little 50 amp fuse, changed it, everything worked! BUT:
it only worked for a few minutes, then blew again. Replaced it again,pop.
Do you think the fan motor could be drawing too much power due to a bad motor? Popping fuses? It sounded pretty rough the other day when I put straight power to it,but the test wires got really hot really quick.
THANK YOU ALL SO MUCH FOR THE INFORMATION! ! I've been looking for a good Jeep sight where people actually answer you.

Yes, the fan is drawing too many amps because of bad bearings or a shorted winding. The best thing now is to replace the fan motor before it toasts the relay.

yup. new fan is in your immediate future