2003 S40. There are two coolant fans on the back of the radiator. When I turn on the AC, only the pass side goes on. Are both fans suppose to go on at the same time as is the case on other cars? I jumped the connectors to the driver's side fan and it operates. Tested the relays and checked the fuses in the engine compartment - all ok. Grateful for any information...

 

Are you having cooling issues? Is the car overheating?

One fan is for normal cooling and the other comes on with the a/c to pull air through the condenser. The 2nd fan runs at a higher speed when the a/c system demans maximum cooling. That being said, I'm not sure if the two fans are tied together in operation. If you let the car sit and idle will the 1st non-a/c fan eventually turn on to help cool?

 

There hasnt been any overheating and the engine temp is constant ~190F. I based my question on my experience with Audi and VW where both fans operate at the same time, either for overheating or AC activation. I recently purchased the '03 S40 and have been repairing the numerous issues I've encountered. In the process of testing the AC, I noticed only the passenger side fan activates. When I unplugged the connector at the driver's side, I found a lot of green residue on the power pin. After cleaning it up and spraying contact cleaner, I reconnected the fan and tried again via the AC - no spin. I noticed the passenger side has its own circuit which leads me to believe its independent of the driver's side (separate sources from the ECM?).

I was going to ask for information regarding the source of the red and blue wires so I can check voltage drops but I think its evident that the driver's fan activates separately from the passenger side. Thanks for the info.

 

When I bought my copy of VIDA it came with another CD of wiring diagrams. Unlike VIDA which requires a 32bit windows pro version to install, the electrical diagrams are run from the CD. Nice to have and it's pretty cheap. I bought mine in 2010 for about $10 on eBay.

 

Are you sure this sensor is good? It's the one with the electrical connector near the upper radiator hose.


Original Engine Management 9394 Coolant Temperature Sensor | eBay

 

Sensor was replaced recently by prior owner. Looks to be OEM.