A/C problem
 

I have a strange electrical problem with my a/c. It keeps turning on and off. The compressor is good, clutch engages, and the relay seems to be working fine, not sure what could be causing this. After the compressor cuts out, if i push the a/c button off and then on again it will start back up again and then cut out after a minute or so.

If your electric side of the AC system is working problem. According to the symptom, it sounds to me that your AC pump is going out.

-AzeKnightz

Either that or your low on refrigerant and the low pressure switch is kicking off the compressor. I'd make sure you have the proper levels in the system and go from there.

Could be a faulty clutch coil as well.

the refrigerant levels should all be fine since i just got it converted to r134a this morning. When he was charging it he had to wire power to the compressor in order to get it to run constantly

Sounds like your low pressure switch is malfunctioning.

Ugh. So many things wrong here.

The system SHOULD NOT need to be hotwired in order to take a charge. Anybody who doesn't know this more than likely can't properly convert a system, or put in the proper amount of refrigerant either.

It sounds like you got a "death kit" conversion this morning...did they disassemble the whole system and flush out all the components? No? You've just decreased the life of your compressor greatly! The proper way to convert is to flush all the old oil out of the system put in R-134a compatible oil, then re-charge with R-134a into a vacuum.

Agreed, that is the proper way to convert R12 to R134a, but that doesn't answer the original question. The compressor clutch stayed engaged when he hotwired the +12v signal to it, so most likely there is nothing currently wrong with the compressor. Instead the problem seems to be that the compressor is getting a intermittent signal from the low pressure switch, that would be my best guess.

But yeah, you should definitely check with your A/C tech to make sure he completely evacuated your R12 system before he added PAG oil and R134a.

I was thinking it might be the low pressure switch too. As for the conversion, the system was evacuated before being charged with r134, but was not dissasembled. Thanks for the input.

Uh....the a/c compressor is SUPPOSED to cycle on and off, ALL a/c systems work this way.
Now if the cycling is excessive or the air doesn't get cooled, then yeah, there is a problem.

As for the 134a conversion, remember the dryer has to be changed also....

Fact of the matter is, we don't have enough information to make an internet diagnosis.

It could, indeed, be the pressure switch, or it could be the fact that it is working as designed, and the system is low on charge, overcharged, or is running a blend of R-12 and R-134a. You forget that that switch is both the high and low pressure cutoff.

It could also be something else entirely. We don't know.

Bottom line is, whoever did the "conversion" either doesn't care or doesn't know what they're doing as evidenced by the fact that they hotwired it and didn't bother to find the underlying cause. More than likely the system is going to die an early death due to this conversion.

If you want the A/C to be reliable and cool well for years to come, then take it to a shop that specializes in A/C work and have them flush the system, and find and fix any leaks. Whether you go back to R-12 or stick with R-134a is up to you. It won't cool as well with R-134a. The systems in these cars is marginal at best, so my car will remain R-12 as long as I own it.

No. Your "A/C tech" is obviously a retard. STAY FAR AWAY.

The problem isn't that its cycling on and off, the problem is that its cycling off and not cycling back on. Even after turning it off and on with the button, it doesnt always turn back on.

One thing i forgot to add, this problem existed before the conversion. I figured the car was low on refrigerant, so thats why I had it converted. There were no leaks tho, so the conversion was probably not necessary and the problem was electrical the entire time.

Nope. Wrong. ALL a/c systems do not work this way. Read up on variable displacement compressors and POA valves.

The RX-7 system is indeed designed to cycle on and off, but it would be HIGHLY unusual for the system to cycle on and off under normal summer conditions since it has such a low capacity.

Ugh. Take it to a decent A/C shop. Tell them what the previous shop did so they can correct the problems the first shop created, and have them fix the underlying issue causing the erratic cycling.

Ah. Thanks for the clarification.

sigh..probably what i'll have to end up doing

The evaporator thermoswitch is often the culprit here. It can be jumpered out to test, but you may experience evaporator freeze ups if you do this. You should be able to search on this and find information as well as a fix or work-around.