Radiator fan always on. - Toyota Nation Forum : Toyota Car and Truck Forums

Fortified Souls · 10-13-2010, 07:30 PM

Well the car is a 2000 camry with 10,100 miles on the rebuilt engine. My question is besides the solenoid in the fuse box what else would cause the radiator fan to always stay on. There are no cels and the car runs like a champ it just takes longer than it needs to warm up until you start driving because the radiator fan stays on all the time. Any Suggestions?

TedL · 10-13-2010, 07:36 PM

Leaving the A/C or defroster on.

By "solenoid", I'm assuming you mean relay.

Bad sensor/wiring reporting high ECT.

rusty9 · 10-13-2010, 07:50 PM

a faulty coolant temp sensor will put the fan into fail safe always on.

Fortified Souls · 10-13-2010, 07:51 PM

Coolant Sensor wouldn't throw a cel? And yes I did mean relay sorry. I know if it was the sensor that supplies the reading for the gauge it wouldn't. I never turn on the front defroster until the car is warmed up but the other day it showed it was warmed up and I turned it on then the temp gauge started to read down and the idle was flickering. (trying to warm car up again I suppose). I opened the hood and low and behold the radiator was on and it was 40F outside according to the Camry. I had to manually warm it up keeping the revs at 1k until there was enough heat to where the fan couldn't dissipate it.

Tech1984 · 10-13-2010, 07:52 PM

Check the sensor on the bottlom of the radiator. Sometimes they corrode or become disconnected.
Be sure the coolant level is constant in the bottle (so there's no air pockets)

Fortified Souls · 10-13-2010, 07:58 PM

The coolant is full and the plastic reservoir reads full. I'll try checking that connector/piece tomorrow.

TedL · 10-13-2010, 08:01 PM

Quote:

Originally Posted by Fortified Souls

Coolant Sensor wouldn't throw a cel? And yes I did mean relay sorry. I know if it was the sensor that supplies the reading for the gauge it wouldn't. I never turn on the front defroster until the car is warmed up but the other day it showed it was warmed up and I turned it on then the temp gauge started to read down and the idle was flickering. (trying to warm car up again I suppose). I opened the hood and low and behold the radiator was on and it was 40F outside according to the Camry. I had to manually warm it up keeping the revs at 1k until there was enough heat to where the fan couldn't dissipate it.

If you have a working thermostat installed, the fan should make negligable difference in how long it takes to warm up, because little to no coolant s/b flowing through the rad.

***fenixus*** · 10-14-2010, 04:09 PM

I agree with the idea of checking the fan coolant switch located in bottom of radiator (usually). I don't think they are monitored by ECU at all, so they don't cause a CEL when disconnected or simply faulty.
disconnected coolant switch will keep fans running 100% of times.

Tech1984 · 10-14-2010, 08:37 PM

Forgot to say, the harness for that sensor runs up from the bottom of the rad to another connector next to the battery. There should be 2 connectors there. one for the rad fan, and the other for the sensor. Check both.

***fenixus*** · 10-14-2010, 09:12 PM

Quote:

Originally Posted by Tech1984

Forgot to say, the harness for that sensor runs up from the bottom of the rad to another connector next to the battery. There should be 2 connectors there. one for the rad fan, and the other for the sensor. Check both.

right, that harness connector should be on the driver side shroud, nearby the fan motor connector.