Originally Posted by
crymar
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.
The pump can be rebuilt sometimes if you are clever with your hands.
There is a thread on it in the "Index of Crossfire ......" .