Troubleshooting LLS - not sure what to do next...

timrec · #1 (**permalink**) 06-13-2007, 11:22 PM

Last summer, I replaced my LLS air compressor, relay and the union (by the master cylinder) on my 2000 Ford Expedition. This fixed my issue with my LLS. However, just today my wife called and said the rear was sagging again.
Here is what I have done so far:
With air suspension switch on, I measured the resistance on the relay between the two small wire terminals. It was infinite resistance.
With relay unplugged, I put a jumper wire between the two large wire terminals in the harness. I started the car. The compressor did not run.
I measured the voltage between the two small wires in the harness (relay still unplugged) and it was around .8v.
I checked the air compressor fuse and it looks fine. I am at a loss. I wouldn't think it would be the compressor already since I just replaced it last summer. Any ideas what I could try next?
thanks.
Tim

High_Horse · #2 (**permalink**) 06-17-2007, 09:25 AM

I'm thinking a bleeding short....the reason being that may have been what killed your first pump. Upon replacment with the new one the short slowing worked on it and burned it out. I would check the connectors for cracking or the like where moisture could get in to cause this.

timrec · #3 (**permalink**) 06-28-2007, 01:41 PM

well, after replacing the compressor and relay the rear still wouldn't rise. I was able to jumper the 12v terminals in the relay connector and get the compressor to turn on, but the rear still wouldn't raise. I took the vehicle to Ford. They determined that a wire in the relay connector was corroded ($215 repair - ouch). I don't really understand why this would have caused my compressor and relay to die though. They were indeed bad. Anyway, I am afraid there is a lingering issue that hasn't been resolved....

High_Horse · #4 (**permalink**) 06-28-2007, 06:26 PM

The thing about vehicles is they run on low voltage and interuptions or shorts will draw power from them and/or blow out something.
Is your vehicle raising now?

Trucker22 · #5 (**permalink**) 07-04-2007, 12:27 AM

Timrec---if I understand correctly---you jumpered the large two wires in the harness connector to the relay and the compressor runs---this effectively takes the relay out of the system--as you know you bypassed it. No way a corroded low voltage terminal in the connector (while it's a common problem since they mount it inside the bumper) could be causing your problem! AND why in the world would they charge that much money to clean up a connection??

My guess is they found something else wrong and repaired it and didn't tell you---that doesn't mean the connector to the relay wasn't corroded--it probably was.

I had to replace my relay and when I did I put silicone grease all over those four connections. That should prevent that from happening in the future. Spark plug boot grease works well. I use the stuff on everything electrical that might corrode--including brake light bulb connections!

Hopefully they did repair something else including the connector and your problems are over.

I just bought a connector that has a schroeder valve on it to replace the union under the master cyl (American Air Suspensions sells it)---that way I can add compressed air to the system when my pump fails---which it will eventually---probably when I'm towing three states away!