Air conditioning question

[rotorjockey]

I need a little help trying to troublshoot my A/C system on a 94 full size blazer.
The A/C system was working intermittently before it died, compressor stopped cycling. I took it to a dealer who said the high and low pressure switches were bad, so I changed them out....no joy. I took it to Firestone who said I had an electrical problem that they could not fix so I took it to an electric shop that pointed out the only way to get the clutch to engage is to bypass both the low and high pressure switches and then tap the clutch. The pressure was low so I charged it back up and I got the clutch to cycle by bypassing the high pressure switch, but it does not blow cold air at all. Is it time to change out the compressor?

 

[BobK]

Well it wouldn't cycle because you were low on refridgerant.

If the A/C pump clutch engages when jumped the clutch is o.k.

The pressure switches disengage the pump clutch when the pressure in the system get's too low(prevent freezeup of the evap. core) and when the pressure gets too high(prevent blowing something up,seals,rubber lines,any number of things can go wrong with high preassures)

You adding more refriderant without know how much,if any,refriderant is left in the system does no good.
Even if there was "some" coolant in the system adding more without cleaning and vacumeing out the system will do no good.

Air,dirt and water(in the form of vapour) will contaminate an A/C system very quickly and render it useless no matter how much refriderant you put in.

My suggestion is take it to a reputable A/C shop and let them do a leak test.

It may be as simple as a O-ring.They can then clean,flush,vacume and refill the A/C system properly.

The do-it-yourself kits they have at walmart are garbage and can damage a system even more.

I guess it all depends on how bad you want a reliable A/C system.