Hey guys im new here and i have a problem with my brothers 1991 toyota camry, 3sfe. His cooling fans stay on even when the car is just started from sitting overnight and stay on, i was fooling with the cooling fan sensor mounted on the thermostat housing i grounded the one wire in the harness and it shut the fans off i always thought it was the oppisite and should turn the fans on when its grounded? i dont want to spend 40 bucks for a new sensor if i dont have to..... any help is appreciated very much tia
Alex

 

The system works the opposite. If the plug is removed from the radiator temp sensor the fans wil come on.

The temp sensor is a bimetalic switch. Check it with an ohmmeter, open above 194F, closed below 181F, temps are averages.

Power power is is controlled by 3 relays. The power to turn on/off the fan control relays should turn off with the ign switch. Not sure on the actual power to the fan itself, it may come directly from the battery through a couple of fuses.

Check the RDI and CDS Fan fuses to determine if they still have power with the ign switch off (and connected to the battery). If so you may have a problem with the fan control relays being stuck in the on position and powering the fans. Or a short in the wiring.

 

Thanks for your response toyomoho, i am going to try to test this as soon as i can, my brother leaves for work as soon as i get home so sometimes its tricky getting a hold of him... thanks again hopefully these test will have my problem solved!

 

On my 99 toyota camry the cooling fans turn on late
The temperature gauege Gos up more then half way the the fans turn on