Re: Strange Air Pump Behavior?
As I reported in my original post, last week my aux air pump kept running after I shut the engine off. I was about 20 miles from home, so I quickly drove home, shut down, and saw that the aux pump was still running. Waited 10 minutes and it finally stopped. Thinking it was a bad relay in the relay module, I replaced the module with a known good spare I had on hand, but the aux pump didn't run when I started the engine cold the next morning. A check with test leads revealed that the pump is kaput. Incredible price range for these pumps - from a $100+ Brand X on eBay to $300+ at an MB dealer to $1,000+ at a Chrysler dealer. Found a Bosch air pump online for less than $200. Looks like the way to go. A question remains. If the relay was OK, how can you explain the aux motor running after engine shutdown? All I can think of is that the relay stuck temporarily to the point where the aux motor burned out.
Last edited by crymar; Sep 1, 2017 at 11:14 AM.