I have a 2000 model Discovery, the suv is sagging in the back and the SLS compressor isnt running at all. I did take the relay out for the SLS pump and did use a jumper wire to make sure the compressor was good, it did run. So it's in the control system or logic. Does anyone have a wiring schematic for the SLS system, or anyone have this same problem, what did it take to fix it???

 

Are you sure you are having a problem with the compressor or electrical end? I just finished finding a fixing a "sagging rear end" issue on my 2000 DII. It was acting very strange (all sorts of dash indicator lights), but turns out it was just a plain old leak in one of the air springs. The best advice I received was to take a spray bottle of soapy water and spray all over the air spring. Look for bubbling to find any leaks. Mine was hard to see. Apparently these things are notorious for leaking at the bottom around the piston. I installed a replacement air bladder (www.arnottindustries.com) and it now drives like new. Hope yours is as simple.