short circuit to batt+ or open circuit - Suspension Inactive

[Dark_stranger]

Have the dreaded suspension inactive message and car is sitting low where I let the air out of the system. Anyway, connected up INPA and get the error...

3 Relay Compressor
Error Frequency : 31
minimun volyage at relay 125.00 mV
short circuit to batt+ or open circuit

I tried pumping up the suspension via INPA and can hear valves opening, but the compressor does not burst into life. This happens on 2 different compressors.

Any ideas?