Cooling fan prob

I have a '98 cavy with a 2.0L engine. It overheated recently, I had to replace the head. I got it back together & now the cooling fan doesn't come on. I have checked the fan motor, relay, & coolant temp sensor. If I check for codes stored in the computer, using a jumper wire it comes on. My friend has a '91 Lumina Euro that is doing the same thing. Nethier one of us has been able to figure this out. Could it be the computer it's self??

OOOOOPPPPS!!!! That should be '89 Cavy NOT '98. Could this be caused by a bad ground??

yes, how did you test the relay?

Ground should be OK if the jumper wire works. I've had old beater cars where the fan quit working, we just wired it to come on with the switch (always ran with engine running). Or you could wire it to a toggle switch. Thats the cheap way out. Relays probably don't cost that much, though. Like Blazer said, how did you test it?

I connected a ground wire to the control side of the relay with the ignition switch on. The relay clicked and the fan came on. I have a toggle switch wired in that is connected to ground, this is how I'm turning the fan on now. What is the normal operating range temperture wise? How hot is to hot. I have a temp gauge installed.


I unpluged the relay and connected the jumper from power to the fan. Does the computer turn the fan on by connecting it to ground? If so this is the griund I was talking about.

My 92 2.2 runs at it's hottest, before the fan comes on, about 180-190º and the fan shuts off around 150º

Sounds like the coolant temp sensor is shot.

Very real possiblility.

i have the same problem with my 95 2.3 cav and i wanted to know i think found the coolant temp sensor. its under the coolant tank right? but arent there more sensors for cooling? like on the engine! i cant seem to find more then that and the fan spins when you start the car but then never comes on when your driving and then you might overheat please let me know anything at all guys.

Coolant temperature sensor should always be in the engine.

your coolant temperature sensor should be on the thermostat housing. just follow the big hose from your radiator to the engine. there will be a little plug pretty close to where the hose and engine meet. that's your temp sensor, however, i would go with the ever so reliable hard-wire. clip the wires going to the fan and ground your negative to the engine block, and run your positive to the fuse block. use a test light to figure out which part of the fuse block comes on only in run, and stick the wire on that section. i did this to my 93 cavy 2.2 and it stays at 150 degrees until you let it cool off.

your coolant temperature sensor should be on the thermostat housing. just follow the big hose from your radiator to the engine. there will be a little plug pretty close to where the hose and engine meet. that's your temp sensor, however, i would go with the ever so reliable hard-wire. clip the wires going to the fan and ground your negative to the engine block, and run your positive to the fuse block. use a test light to figure out which part of the fuse block comes on only in run, and stick the wire on that section. i did this to my 93 cavy 2.2 and it stays at 150 degrees until you let it cool off.

thank you so much that is what im going to do to fix it. i like the hard wire version better. plus it will go off when i turn the car off and thats really what im looking for.