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Need to pick the brains of the Car Talk Crew!

I need help figuring out why my 2000 Honda Civic DX Coupe radiator fan isn’t working. I have a manual override switch in the meantime, until I can figure out what is wrong.

My local repair shop wants $140 just for an estimate!

Does anyone know if there are better places to get estimates, and once the estimate is done, will they replace my manual override switch? I think that they probably would not want to replace it.

If it was a thermostat problem, would the thermostat on my dashboard work?

Is it cheaper to buy the parts for all of the potential problems rather than pay for the estimate?

Does a radiator fan stay on once the car has reached a certain temperature? Or does it cycle on and off? I worry that my leaving the fan on when I am driving may affect the battery.

If your Honda has A/C, then the fan should run anytime the A/C or defroster is on. Is that the case? If so, it’s almost certainly the temperature sensor in the block near the thermostat. (There may be more than one).

If the A/C will NOT cause the fan to run, but your hot-wire will, then it’s probably the fan RELAY, which will be hidden away somewhere…

Go to the AutoZone website and register. They have a “Repair Info” section. Go through the prompts until you find Chassis Electrical and then Wiring Diagrams.
The site is a pain in the ahem but since you mentioned previously your friend did the workaround maybe he can sort through the schematic.

A shop will not give you an estimate on an electrical problem because there is simply no way of knowing whether tracking down the problem will take 10 minutes or 6 hours; not to mention there is no way of knowing what parts would be needed.

Leaving the fan on won’t hurt anything. Many people over the years have done what you’ve done and allowed the fan to run every minute the engine is running during warm weather or stop and go traffic.

Find the radiator temp sensor for the fan. From my hazy memory it seems a ground is provided for the relay through this sensor. Simply ground that wire or wires and if the fan comes on then the sensor is likely bad. If so, not a big deal. If it does not come on then it’s time to revist a few fuse issues and check the relay.

No A/C, and the manual override is attached to the relay receptor (the part that plugs into to the relay doesn’t test for power, but the relay receiver does test or show power). I called the automechanic, but when I tried to get an idea of the various things that could be wrong and the price estimates to fix, they seemed hesitant to tell me.

Sometimes, it's the radiator fan switch which is bad.

thank you! I am going to check out that website. Being able to get a picture of what is going on in my car is really important to me. I feel weird trying to describe something and not knowing the proper name and getting blank stares from people. :slight_smile:

OK nailed it…