Unplug Coolant Temp Switch and the Fan comes on!!??!!

[kbelky]

92 Celica GT. Auto. While troubleshooting my overheating problem, the manual suggests disconnecting the coolant temp switch from the radiator and grounding it to the block with the ignition switch on. Problem is, when I disconnect the switch with the ignition on, the fan spins. No grounding necessary. Is this telling me that the coolant switch is bad.... or the relay is bad? Why don't they cover that scenario in the manual?

[Luckynumber5]

no thats normal, when the switches heat up the same thing happens inside the switch, I think what it means is ground the switch after you take it off and the fan should stop spinning, dunno I've only used that to make sure my fans are good...

[Dr Tweak]

Originally Posted by Luckynumber5

no thats normal, when the switches heat up the same thing happens inside the switch, I think what it means is ground the switch after you take it off and the fan should stop spinning, dunno I've only used that to make sure my fans are good...

That's exactly why it's done that way, so that if the circut fails, the worst thing that happens is your engine runs too cool, rather than overheat!

[canadiancelica]

Originally Posted by kbelky

92 Celica GT. Auto. While troubleshooting my overheating problem, the manual suggests disconnecting the coolant temp switch from the radiator and grounding it to the block with the ignition switch on. Problem is, when I disconnect the switch with the ignition on, the fan spins. No grounding necessary. Is this telling me that the coolant switch is bad.... or the relay is bad? Why don't they cover that scenario in the manual?

Overheating problem is likely caused by one(or more) of the following, from experience with my 91 GT anyways.

-Air locked engine (most common)
-Stuck thermostat (second most common)
-clogged radiator (from deterioration) -reccomend flush and replacement of thermostat
-Failing water pump (not known to cause overheat cause it still spins, but it may be leaking causing a pressure leak)
-Bad headgasket (not common atall for 5sfe)

Hope I helped out