I am working on my wife's 2000 civic EX AC system since it was working and then stopped blowing cold. I immediately checked for the compressor clutch to engage but it did not. I checked the fuses and all checked good. I checked for voltage at the compressor and there was none so I swapped relays with no joy. I then jumped one of the powered terminals where the relay would go right to the compressor terminal of that relay and the clutch engaged. At this point we consulted the wiring diagram and expected that we had a bad ground and the relay wasn't pulling the switch, but what we thought would be the ground went into the powertrain control module. We were at a slight loss here and are continuing to troubleshoot but would love any input from anyone who has seen this. Thanks in advance!

 

In addition to the compressor clutch not engaging, does the condenser fan also not run?

Do the fan and clutch relays get battery voltage at terminals 2 and 4 from fuses 56 and 17?

 

Yes they do get voltage and the fan does run (sorry we had already checked that but i forgot to add it into the description). I think we found the problem though. We jumped the high low pressure switch above the receiver drier and the clutch engaged. I either have a leak or the switch is bad. My guess is a leak..... I just hate spending all the money on dye and coolant to check it. What do you all think?

 

Rent (free) a manifold gauge set to see whether the refrigerant pressures are low.