Cooling fan/electrical issue

[Kanding]

Hi guys,


My cooling fan is always on in my 93 Prizm. I checked the ECT switch on the thermostat as well as the cooling fan relays, all are ok. The only other problem that I can see that would cause this is a broken/loose connection in the wiring somewhere. Any ideas before I start testing the cooling system wiring for continuity (not looking forward to this)?

[retiredat44]

faulty temp sensor to coolant maybe?
those damned sensors are expensive. I replaced 2 one day and paid about $50.00 at autozone.

Anyone else have a guess?

unless your engine is overheating..... and the sensors read the correct temp..

[Kanding]

Originally Posted by retiredat44

faulty temp sensor to coolant maybe?
those damned sensors are expensive. I replaced 2 one day and paid about $50.00 at autozone.

Anyone else have a guess?

unless your engine is overheating..... and the sensors read the correct temp..

Thanks for your thoughts. Since the ECT switch is controlled by the thermostat, and it works correctly, I think the thermo is ok, or at least, not the problem. If I unplug the fan and let the car sit, it heats up as it should and the initial high (cold) idle lowers, seemingly correctly.

[niko3257]

not to good with this stuff but would a A/C switch do it?
doesn't the fan run when the switch is on?
if it does could the switch be bad?
not sure but you could check it.

[90 GP]

The switch on the thermostat housing should have different ohm readings for different temps. You would have to check specs in repair manual and use meter to check values. If that checks out I would strongly suspect the relay.