Greetings,

As things get hot in the northeast I want to make sure everything is functioning properly. After a long run on the warmer weekend I didn't hear my after run pump when I shut the car down. I did let it idle for several minutes before shutdown, however.

Suspecting the pump or switch, I popped the connector off the switch (the one often replaced with a lower temp model to induce more cooling) and jumped the contacts on the harness. Nothing happened. I would have expected the aux fan to at least come on. To be fair, the car is stone cold and hasn't run for a few days, so it might just be too smart for a simple jump of a single contact. Does anybody have any input as to how I might test the pump and switch without major disassembly?

Thank you!

 

Never mind. Answered my own question. The car is smart enough not to leave voltage going to the switch. By running the car, jumping the connector, and turning the car off, I got the pump and fan to run.

A torch to the switch doesn't get continuity, however, so I do have a bad switch. Stock green or blue low temp?

 

BLUE!!!! that aux. water pump rarely even turns on with the stock switch.

 

On my 01 S4, my aux fan will run on at times with no reason or pattern. Mostly it will run on low for a while, but other times after shutdown it will come back on on the high setting & will not stop until I pull the 60 amp fuse for a second. I didn't notice this until I installed a blue pump switch that has never run the pump. I haven't owned car long enough to know the history, but I just replaced the water pump, therm housing & all of the belts etc. Is this possibly a fan control unit problem or fan therm switch??
Thanks, steve