Looking for some experienced help with radiator fan/AC issue?
I have replaced nearly every single sensor/component trying to diagnose my Air conditioning system. I have referenced the A4 Air Conditioning Control Circuit Troubleshooting guide.
First thing to check is if you get the low speed radiator fan when you turn on the AC switch.
I get nothing.
I have replaced both fans, the Fan Control Module, The fuse panel on top of the battery, the thermal fan switch (screwed in radiator), the coolant temp sensor (back of engine), the ambient air sensor (in cowl area near windshield wiper mechanism). I have even cleaned all the electrical circuits to ground (under battery and cowl area).
I have tested the fan system using a jumper wire. I find that the fans do turn on low (jumper 1-2), and high when the ignition is on (jumper 2&3). So coolant fans and circuits show they should be running properly. All posts lead to a bad coolant temp switch. I bought 2 switches, and tested them in boiling water. They showed continuity near 200°F.
When put in the car, the fans do kick on low speed when the coolant temperature reaches around 99°C.
Yet- When I press the AC button, the fans do NOT automatically turn on low speed.
What is the circuit path that gives the fans power when the AC switch is pressed?
What else could be bad? The AC switch itself? The computer?
I have replaced nearly every single sensor/component trying to diagnose my Air conditioning system. I have referenced the A4 Air Conditioning Control Circuit Troubleshooting guide.
First thing to check is if you get the low speed radiator fan when you turn on the AC switch.
I get nothing.
I have replaced both fans, the Fan Control Module, The fuse panel on top of the battery, the thermal fan switch (screwed in radiator), the coolant temp sensor (back of engine), the ambient air sensor (in cowl area near windshield wiper mechanism). I have even cleaned all the electrical circuits to ground (under battery and cowl area).
I have tested the fan system using a jumper wire. I find that the fans do turn on low (jumper 1-2), and high when the ignition is on (jumper 2&3). So coolant fans and circuits show they should be running properly. All posts lead to a bad coolant temp switch. I bought 2 switches, and tested them in boiling water. They showed continuity near 200°F.
When put in the car, the fans do kick on low speed when the coolant temperature reaches around 99°C.
Yet- When I press the AC button, the fans do NOT automatically turn on low speed.
What is the circuit path that gives the fans power when the AC switch is pressed?
What else could be bad? The AC switch itself? The computer?