Q about e-fan auto on programming.

On my 1990 XJ Limited, should the electric fan go on automatically at 218* and/or when the defroster or A/C goes on? That's the way it worked on my 96 XJ, but with this beater I have now, I can't make the fan go on. Also, I tested it directly to the battery, and the fan works. Just wondering if I have a wiring problem, PCM problem, or no problem. Thanks.

Oh yeah, and amazingly I don't have even any hint of overheating, but I'm so paranoid after the 1 year nightmare with the 96, that I'm worried that this one is going to overheat when I'm hunting with it in the high country during summer.

If your 90 is like my 89 and I remember right, should be a relay on the left fender.

...and are you using the temp switch on the radiator or some other set-up??



This is the temp switch for the RENIX fan. It just powers the relay, does not have any other function. This switch is non-existent on 91+.

Hey, sorry guys maybe my question was unclear. Is the temp switch the only thing that turns on the electric fan? On the newer XJ's, turning on the defroster or the A/C also turned on the electric fan.

Planetcat said:

Hey, sorry guys maybe my question was unclear. Is the temp switch the only thing that turns on the electric fan? On the newer XJ's, turning on the defroster or the A/C also turned on the electric fan.

Click to expand...

The temp switch and the defrost/AC both should activate the fan. If the defrost/AC operates the fan but it does not come on when hot, then the temp switch is most likely the problem. If neither condition turns on the fan, then the relay is where I would start. Try jumping across the connector for the temp switch and see if the fan comes on.

DieselSJ said:

The temp switch and the defrost/AC both should activate the fan. If the defrost/AC operates the fan but it does not come on when hot, then the temp switch is most likely the problem. If neither condition turns on the fan, then the relay is where I would start. Try jumping across the connector for the temp switch and see if the fan comes on.

Click to expand...

Ok, now it's clear. For sure, the defrost and A/C do NOT turn on the fan. I can't create an overheat condition to see if the temp switch is working, which is somewhat worrisome. At least I know to check the relay no matter what, since the defrost/AC don't activate it. I'll look for the relay on the left fender. Thanks.

Planetcat said:

Ok, now it's clear. For sure, the defrost and A/C do NOT turn on the fan. I can't create an overheat condition to see if the temp switch is working, which is somewhat worrisome. At least I know to check the relay no matter what, since the defrost/AC don't activate it. I'll look for the relay on the left fender. Thanks.

Click to expand...

You can jump across the connector for the temp switch...