Self Levelling Suspension??

Hi there, im a proud owner of a TD5 2001 manual disco and i love it!! However since this cold spell ive been having problems with the self levelling suspension. Her back end is now fixed to a low position, sometimes even catching ramps/speed bumps!! I used to hear a hissing noice when turning her off, but now i dont? Ive found a 30 amp fuse in the engine bay which had blown, this was replaced, when turing ignition back on etc pressed button to try rasing her it blewthat same fuse? Any ideas what might be causing this? also what sort of price am im looking at to get this fixed?

Also ive noticed that the heaters will blow out warm air, then cold air back to warm? Is this normal? again help please?

Looking forward to the replies

KC

The height sensors for the SLS could be all iced up. They are small plastic levers near the air bags.

I have got the same problem, the compressor is freezing up, I used a hair dryer to defrost it, this stooped the fuse blowing and the system inflated, it must have some water residue in the system. I have taken my compressor off dried it on a radiator for a couple of hours and blow all the the lines out with an an air line, since then the system has been functioning correctly.