Hi, I have a 1998 Audi A4 2.8. I have been having a problem with a fan staying on once I turn the car off and it often drains my battery. I replaced the battery originally only to find that this was not the problem. After doing some research I discovered the fan I hear is the secondary air injection pump, and that the relay for it needs to be replaced. I have the replacement relay but absolutely cannot find where the relay switch is located. Any help would be greatly appreciated!

 

The SAI pump relay is actually in the ECU box on the drivers side of the engine compartment (up near the windshield). I think you need to remove five 10mm hex screws to get the black box open

It should be one of those on the left... (not my pic)

 

I will check this location tomorrow to see if the relay is there but I am almost certain I checked there a few months back and the relay was not located there. Maybe because this is a 1998?? I will check again and let you know...thank you for your help!

 

Check for water around said relay. Make sure the cowl isn't clogged with debris and water has backed up into the ECM and relay water box. If this is the case, pull out the battery and tray and unclog the drains.

The water box is the black box on the driver's side of your car, below the windshield. It's in the same cowl section as the battery.