I just bought a prelude and one of the many small problems on the car is the AC compressor will not come on. There is a problem with the HVAC unit because sometimes none of the lights turn on but if I hit the dash (solves all) both the lights and the AC light comes on. However, the actual AC compressor will not activate. The wire from the AC unit to the harness is connected properly.

What should I do?

 

what year prelude. if its not r134a, get it vacculated and recharged. if it is r134a, grab a gauge from walmart and hook it up and see if you are low on pressure. If so get a can of r134a and add it.

 

opps, its on a 92, so it still has the R12. However, will a low charge cause the compressor to not turn on (somehow I doubt it)

 

yes there is a pressure sensor on the reciver. if pressure is to low it will not engage

 

Did you ever get an answer to this?

 

purge the lines and convert to r134a with a sealer and dye

 

I'm suprised noone has told you to pull all the AC lines and components yet... LoL

 

Bring it to a shop, that R12 **** is nasty for the air, yes a low pressure will trip your compressor off so it doesnt damage itself. A shop will do a vaccum test and repair any leaks then replace the R12 with R134.