today fired up AC to clean interior a bit of nasty humidity - couldn't do a piece of it. i pop the hood and AC compressor doesn't spin. i shut the car down and check the 2-pin-cable. constant 9v. (ac on or off - doesn't matter) - i think the relay contacts got in lovely wedding... what could it be beside this, where can i find AC relay (and/or relay box?)

Thanks (the connector i measured is located almost at middle of car, on one end of ACCompressor, and i hope compressor clutch isn't burnt out)

cheers, thx!

The a/c won't come on if the temperature is below 5degC. It is by design.

today fired up AC to clean interior a bit of nasty humidity - couldn't do a piece of it. i pop the hood and AC compressor doesn't spin. i shut the car down and check the 2-pin-cable. constant 9v. (ac on or off - doesn't matter) - i think the relay contacts got in lovely wedding... what could it be beside this, where can i find AC relay (and/or relay box?)

Thanks (the connector i measured is located almost at middle of car, on one end of ACCompressor, and i hope compressor clutch isn't burnt out)

cheers, thx!

Relays have no sense. magnetic clutch has 4ohms of resistance. all tried, it turned up only once. i unplug 10a fuse for ac - both cooling fans go up... still 9.15volts there, i plug in 9v bulb on - no light (couple mAs maybe?)

D@mn! :(

Relays have no sense. magnetic clutch has 4ohms of resistance. all tried, it turned up only once. i unplug 10a fuse for ac - both cooling fans go up... still 9.15volts there, i plug in 9v bulb on - no light (couple mAs maybe?)

D@mn! :(

There is no relay. The a/c switch controls the mag clutch directly. If you are directly powering the magnetic element of the clutch and it still isn't working, there is a good chance that part of the a/c clutch has fallen off the compressor. If you look inside the a/c compressor pulley, can you see a disc with a triangular plate on it?

Err if you read rwbaldwin's post you'll see that the aircon won't come on unless the temps over 5 degrees. It's to stop the condensor from being damaged from the cold.

Err if you read rwbaldwin's post you'll see that the aircon won't come on unless the temps over 5 degrees. It's to stop the condensor from being damaged from the cold.

On opened space it was -2... in my garage its always warmer (delta T usualy is 3 or 4degC...) so i think it couldn't be it. but hey, it ran ONCE(?) but never again?

There is no relay. The a/c switch controls the mag clutch directly. If you are directly powering the magnetic element of the clutch and it still isn't working, there is a good chance that part of the a/c clutch has fallen off the compressor. If you look inside the a/c compressor pulley, can you see a disc with a triangular plate on it?

Yeah i realised that. if i look on the side where a belt runs pulley, you mean? hell i see the outter ring (which spins from engine) and i also see the inner ring (which is from compressor, as heard from father) - not matter what i do, it doesnt spin (at least once it did, doh) - so far everything looks as in perfect shape, at least from outside.

but still - can you give me hint how to get to the connector to supply power to mag-clutch? its freaking hard from "position-above". hell i still dont get the 9.15v with almost 0amps.

On opened space it was -2... in my garage its always warmer (delta T usualy is 3 or 4degC...) so i think it couldn't be it. but hey, it ran ONCE(?) but never again?

Yeah, so -2 degC + 4 degC = +2 degC. STILL <5 degC! What part of 'The a/c won't come on if the temperature is below 5degC' are you struggling to understand?

How long did it run for this one time it ran? The over-ride signal for temperatures <5 degC comes from the exterior temperature sensor behind the front bumper. I would say that there was a pocket of air around the sensor (perhaps having trapped some heat from the engine) which was warmer than 5 degC, but once this dispersed and was replaced with ambient air (perhaps when you opened the bonnet), the over-ride kicked in and the A/C shut down.

You clearly have access to some diagnostic kit, but why not check whether it IS what rwbaldwin says by aiming a fan heater at the front of the car to heat up the air around the sensor to >5 degC, and then see if it works again? I really do think you're overcomplicating matters...

Sorry that was inevitable!

the AC temp switch is under the scuttle panel next to the pollen filter, it looks just like a coolant temp one but rattles when you shake it lol, try warming that up with a hair dryer etc then see if it comes on

oh **** damn i thought it is for -5C. (but why did it work 2days ago when temp was around 0?

sorry but i still think its not just the 5c barrier. why did it turn on once then?

(edit, i tried to turn it up for about 5 mins, then after having engine shut down for min or so, turned up and it works, for min, then i shut AC, turn it on again, no workie)

Edited 10 December, 201015 yr by watts

Ah, when you put it like that, my money's on the evaporator temperature sensor (assuming the Octavia A/C bears a passing resemblance to the Fabia's). For whatever reason, when that goes the A/C works the first time you start the car from cold, but doesn't work again until the car's completely cold again...

Not a very easy job, I'm afraid!