I just fixed my radiator cap which wasn't holding enough pressure causing the coolant to come out of the overflow well before the needle peaked. Now the needle will peak when it is sitting still, but the fan no longer turns on. It did at the start of the season. I'm not sure what to check for on these. Has anyone had this problem and fixed it?

 

A couple of quick checks are to 1) check the fan fuse and 2) remove and ground the wire connected to the fan thermoswitch (screwed into the bottom of the radiator). The fan should run when this wire is grounded. If not report back.

 

But it's not running. You said it should run when the wire is grounded, removing that wire wouldn't test anything then, it should still not run. I checked the fuse, it's good.

 

When you remove the wire and connect it to ground you are duplicating what the switch does when the coolant gets hot. Therefore, if you disconnect this wire and connect the wire to ground (a nearby bolt head works good) then the fan should turn on. This is assuming you have the ignition turned on.

If the fan is not coming on when you ground this wire then something upstream is bad. Could be a broken wire, bad fuse, corroded connection, or the fan could be bad.

Do you have a multi-meter and know how to make voltage and resistance measurements?

 

Yeah, I used to work with electricity a lot. I figured someone who has troubleshot it before could fill me in though.