My A/C pump always intermittently started and stopped whilst it mainted temperature. The disc on the back of the pump clicked on and off about once every 30 seconds. Now, it's permanently-on, unless switched off. Now and then it will work correctly (so is an intermittent fault) but does anyone know how to correct this -is it controlled by some kind of relay/servo that's serviceable?

thanks
Andrew

 

do you mean the a/c compressor? if so it is controlled the low and high pressure switch and should cycle on and off. if it stuck on then do not use it or the system will freeze up. check the low pressure switch it is probly going bad not cutting the compressor off

 

Armac,
I've got a similar problem but opposite of Andrew's. Not to intrude or change the subject but my ac worked great 'til a few days ago. Now the compressor doesn't engage or make a sound at all (no fan engagement either - nothing) when I turn on the ac. Is the low pressure switch you mentioned earlier gone bad? Driving without ac in Florida sucks... Help!

nForm91

 

If it's full of freon, the pump can run constantly without causing a problem. Mine will only cycle when the fan is turned down and I'm driving down the highway. Any other time and it runs constant. It will sit and idle with the A/C compressor running constant. I haven't touched the A/C system since I've had it--9 years. If you do get a constant on-off-on-off then you may be low on freon.