Hi Experts, My car's radiator cooling fan (suction fan) would not turn on as the car reaches beyond normal operating temp (used to be 80 degrees - now nothing even at 100+). The fan has integrated controller which is fine (at least based on what i have observed so far). This is what I did initially:
1) Tried 2 different fans, thinking the fan circuit was bad. The fan has power on red wire, ground was good and 3rd pin on the fan connector had 12v. No bad fuses.
2) When my AC used to work (now I am getting 1256 error), I used a code reader and found zero fan demand by engine demand and 20% demand by AC? Seemed like computer is detecting car being hot although temp gauge was showing 100 deg. No luck with either of the fans.
3) I then performed another test (should have done even before trying two other fans) - I disconnected PCM pin on the fan connector. The fan turned on at full speed (as expected because fan lost computer signal and protection kicked in). I confirmed and the other two fines behave the same way.
4) Next I wanted to check if Coolant Temperature Sensor was different from sensor Temperature Gauge. I disconnected the coolant sensor connect at the engine block. The temp gauge displayed zero and the fan immediately turned on at full speed (seems like computer detected open sensor and protection kicked in. This has established that there is one common temp sensor and the computer PCM driver works.
Now at this stage I am puzzled. Any ideas what I can try next (I have ordered temperature sensor for $10 - just in case).
Appreciate any clues. If things don't workout, I will create an alternate way to turn on the fan (of course it will run at full speed every time temp will reach 80 deg).
Thanks
1) Tried 2 different fans, thinking the fan circuit was bad. The fan has power on red wire, ground was good and 3rd pin on the fan connector had 12v. No bad fuses.
2) When my AC used to work (now I am getting 1256 error), I used a code reader and found zero fan demand by engine demand and 20% demand by AC? Seemed like computer is detecting car being hot although temp gauge was showing 100 deg. No luck with either of the fans.
3) I then performed another test (should have done even before trying two other fans) - I disconnected PCM pin on the fan connector. The fan turned on at full speed (as expected because fan lost computer signal and protection kicked in). I confirmed and the other two fines behave the same way.
4) Next I wanted to check if Coolant Temperature Sensor was different from sensor Temperature Gauge. I disconnected the coolant sensor connect at the engine block. The temp gauge displayed zero and the fan immediately turned on at full speed (seems like computer detected open sensor and protection kicked in. This has established that there is one common temp sensor and the computer PCM driver works.
Now at this stage I am puzzled. Any ideas what I can try next (I have ordered temperature sensor for $10 - just in case).
Appreciate any clues. If things don't workout, I will create an alternate way to turn on the fan (of course it will run at full speed every time temp will reach 80 deg).
Thanks