Ended up having to put a new radiator in my 00 XJ. Got everything back together and let it run to make sure everything was good. The electric cooling fan never kicked on. It gets up to 210 maybe a little more than the temp statrs to drop. I plugged in another known working fan thinking that was the issue but it still didnt kick on. I also tried the relay under the hood. Is there only a certain time this fan kicks on? I even tried with the ac running and still notta. Am I missing something?

 

IIRC with a 2000 it should come on with the AC unless the speed sensor says you are a' cruzen. Also it doesn't come on until about 218*. Also on my old thing it comes on with defrost for some reason. If, (and only if), it's not coming on, and the AC clutch IS engaging, you likely do have a problem. MY fan relay is alone on the left inner fender. Wherever yours is, I'd check/clean the blade connector where the relay plugs in...for a start. If the AC clutch is not engaging when you turn it on, then the fan may well not come on also. Some sort of voodoo.

Edit. I suppose a guy could put some cardboard or something, FRONT of the rad and see if the thermal switch kicks it on about 220*...., should come on with the AC clutch though, I think.

What I mean is, the thermal switch is pretty simple. The workings of how the AC signals it are more complicated.

 

I believe on '00-'01, efan turns on when a/c line pressure reaches X psi or 218 coolant temp. '99 down efan turns on with compressor engagement or 218 coolant temp.