I just wanted to know what could cause the system to be _completely_
dead, because usually the fans at least turn on. I tried posting about a
week ago with a hugely long description and didn't get a single response.

i've gone through and tested the following components, which tested OK:

low pressure switch
a/c thermostat
a/c delay timer
a/c relay
clutch relay
a/c clutch
a/c diode
radiator fan relay
a/c switch

none of the relays are even getting a signal. is there some control box
that the button goes to that might be bad?

Thanks
-James

John S. wrote:
> Is there some reason you didn't include this in the first message? The
> first message reads like someone who knows nothing about cars.
>
>
> Masospaghetti wrote:
>> wrote:
>>> Pete C. wrote:
>>>> Masospaghetti wrote:
>>>>> Hey all,
>>>>>
>>>>> Car is a 1986 Honda CRX. Where should I start looking for trouble if
>>>>> pushing the A/C button does _nothing_? No increased idle, no condenser
>>>>> fan, and obviously no cooling. the only thing that happens is the little
>>>>> "A/C" light turns on.
>>>>>
>>>>> Thanks
>>>>> James
>>> Most likely due to an empty system. The low pressure switch is
>>> preventing the clutch from engaging.
>> The system has plenty of refrigerant. I would have expected that the at
>> least the condenser fan and boosted idle to kick in if it was just low
>> on refrigerant.
>>
>> I tried jumping the clutch relay and the compressor engages. the system
>> actually cools extremely well.
>>
>> I figured it would be low refrigerant when I first saw the car too, but
>> I pushed on the low-side schrader and got a huge blast coming out.
>>
>>> To diagnose, find the LPS on the accumulator and jumper the connection
>>> while the a/c is on. If the clutch kicks in, that is the problem.
>>> Don't run it for long. Just verify the clutch kicks in. If the clutch
>>> does not engage, you have other problems. Get a manual and a DVM and
>>> start tracing.
>>>
>>> With an old R-12 system, it will probably not be cost effective to get
>>> it fixed and charged with R-12.
>>>
>>> What I would recommend, providing you have the tools, is to convert to
>>> R-134.
>>>
>>> First you need to figure out where the R-12 leaked out. Most likely on
>>> the high pressure(hot side) of the compressor. Probably the crimp
>>> right next to the compressor.
>>>
>>> Replace whatever is leaking. Replace all of the o-rings in the system.
>>> Replace the orifice tube. Replace the accumulator.
>>>
>>> Drain all of the oil you can out of the hoses/system.
>>>
>>> You can get little adapter ports to change the R-12 ports to R-134.
>>> Get those and screw onto your existing ports.
>>>
>>> Fill the system with the recommended amount of PAG oil(it will say on
>>> the compressor).
>>>
>>> Seal the sytem up. Evacuate the system(requires a vacuum pump).
>>>
>>> Charge with 80% of the recommended charge for R-12 with R-134a.
>>>
>>> Enjoy the cold.
>>>
>> thanks for the advice.
>