Question: Accord - Is 'Thermo-Switch' the Same as a 'Fan Sensor?'

Hello:

I'm having a mysterious problem with overheating under load on my '92
accord lx. The meter goes up past the 3/4 mark when going up steep
hills, and the problem seems to be getting worse. The local Honda
place claims to have tried most major sensors, including the engine
coolant temperature sensor, the fan sensor, the gauge sensor, and the
thermostat. The water pump is brand new, and so is the radiator. No
white smoke, so I don't think its a blown gasket. My question: is the
so-called "thermo-switch" the SAME thing as "fan sensor"? If not, I
thought it might be worth replacing to see if this will fix the issue.
Thanks in advance for any help on this. - Paul

 

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Wow, I hope they aren't 'trying' all this stuff at YOUR expense ! !
They're just supposed to FIX it, not conduct training sessions in the
repair bay.

If it's not losing coolant, and the reservoir level is consistantly at
the FULL mark on the plastic tank, (are you sure it is?) what happens if
you crank the HEATER on full when climbing the hills? (other than
sweating) Does the guage go to normal?

Do the fans come on when sitting in traffic, or never? Do they come on
when AC is engaged (if you have AC)? I've heard that some models have
TWO temp sensors, but I'm no expert.

'Curly'

 

http://www.honda.co.uk/owner/AccordManual/400/16-103.pdf shows the electrical
controls for your car's cooling fan.

Might you mean "the fan relay" when you write "fan sensor"?

Thermostats, coolant temperature switches, and the fan relay are popular failure
items. But if it was one of these, then I'd be surprised your local Honda shop
didn't catch it.

 

Yes, they are the same. Honda calls it a "Coolant Temperature Switch",
the generic term is a thermo switch. Calling it a fan sensor is somewhat
imprecise.

Does the car ever overheat on idle, or is it ONLY during load? Do you
ever hear the cooling fan come on?

 

I looked at a 1992 Accord wiring diagram, there are two engine
temperature switches and a "Radiator Fan Control Module" that control
the radiator fan motor. The Thermoswitch is part of the Air
conditioning circuit and is not in the circuit when the air
conditioning is turned off, it controls the second fan.

Did you have this problem before replacing the radiator, if not verify
if the new radiator core has the correct capacity. I had an under
capacity replacement radiator in my Saab...used to over heat like you
are describing.

Check all the grounds on the cooling system. Both temperature switches
and both fans have one side grounded to chassis (Black wire).

I wish you luck.