Thread: P1651 - fan 1 relay control circuit

I have a 97 GP with the 3.1L engine. The check engine light is on and it is throwing a P1651 Fan 1 relay control circuit. I checked the fuse and the relay and they are good. If I jump the fan switch contacts under the relay, the fan comes on and runs perfectly. but when I check the coil side of the relay the always hot (12 V) pin is only reading about 3 - 4 volts. Since the PCM on this year (97) is ground side switched, it is not the source of the 12 volts.

My question is what is the internal circuit for the supply voltage for the coil for the Fan 1 relay? I'm sure it has a fuse. Does it come from a power source right in the Fuse Relay center or does it come from elsewhere?

I tried to remove the fuse/relay center and look underneath it. It is very tight with all the wiring harness. I unscrewed the cabling connector but couldn't get it to totally unplug. I tightened it back down and just like that I had full voltage (12v) on the fan coil. yeah. but twenty miles later the bad connection came back and set the SES light again. Anyone had this problem? Any help greatly appreciated.

There must not be to many code P1651 problems out there. My first attempt at bypassing the faulty supply voltage was to run a jumper wire from the supply voltage side of the Fan 2 coil. This worked for about 15 miles and then logged the same P1651 code again. This tells me that both of these coils draw their voltage from a common voltage source and that source is equally flakey for both of them. I will now try to jump from a completely different source and see if the code comes back. I wish I knew what size inline fuse to use?

Any help is appreciated.