Rear Air Suspension Question

[Blue)(Fusion]

I'm helping a friend look for a Crown Victoria and he found one he really likes for a very good price, a 1996 Crown Vic with the Handling & Performance Package.

Our only concern with it is the rear air suspension. To me it looks like it may be sagging, but I'm not too familar with looking at the pre-98 bodies. I checked the switch in the trunk and it is on. I did not hear the compressor running, but the mechanical fan is also loud so I can't be sure. There was no CEL and not sure if a RAS failure would show up on there.

How can I diagnose what is wrong before I get it? It didn't look like there was any leakage of the air bladders and drove great. I'm thinking either a problem with the level switch or the compressor. Any way to diagnose before we make a deal with the dealer?

Also a side question, around the ABS valve system, there are two metal lines, which to me look just like brake lines not attached to anything in the engine bay. The ABS light was on and the brakes were hard to push, but not as hard as if the brake booster was not working. I looked quickly and all of the same brake lines were connected to the ABS module as my '00 Marquis so I don't know what these two lines are for. Any ideas?