I have lost the AC in my car recently (just in time for summer). Car is 2000tj with ~130km Had a quick look at it today. There is gas in the system (released some out of the valve). Engine revs pick up when ac switched on. Light comes on on AC button. Checked fuses all ok. adjusting the temp control in the car from hot to cold works (cold only being room temp). Belt tension seems ok, Pulley wheel is turning but not the cap on the end of the pulley wheel with what looks like 3 balance weights on them, I would have thought this would have turned with the compressor/pulley wheel and is there to hold the puley wheel on. Or does it transfer the power from the pulley wheel throught to the compressor

Is it just that my compressor is stuffed or could it be something else? Anyone got any advice?

Sounds Like You Have No Power To Clutch

Does the end cap to the pulley wheel act as a clutch so it slips if the compressor locks up.

In the TR model there are 2 relays for air con. One is for the compressor clutch and the other for the fan behind the radiator.

These relays do fail and one indication is that the plastic round the pins melts. Look for that and also try another relay. Say temporarily swap the head light high beam relay for the a/c Comp relay. On the TR the relays are in the main fuse box under the bonnet and I guess the same will be true of the TJ. Repco, Autobarn etc will have relays.

Rob

What type of switching mechanism is there in the compressor? What turns the compresor on when you turn the ac on?

a magnetic clutch 1 wire needs + thats all

if system low on gas it wont turn on

Should the end cap on the pulley wheel be able to move by hand? When compressors are out i know they can spin fairly easily

yes it should spin with some friction

it will turn roughly 180 degrees -turning it through 180 feels like pull starting a lawn mower (ie is compressing maybe) then it is impossible to turn.

I bridged the terminals on the coolant level senosor at a sugestion of a friend in case the gas level was too low, had no affect.

i also swapped the relays and re checked all the fuses.

I belive the compressor is seized
How would i go about confirming this?


Ps - thanks for the help so far

the only reason your compressor will sieze if if there is a leak (refrigerant and oil will leak out the hole)..but you musn't have one as you claim there is gas in the system....also you must have gas in the system as your compressor is turning on...if there is no pressure the LP switch (low pressure switch) will lock out the compressor..

it is however possible the valve's on your compressor are rooted as they are nylon...car ac's are ment to be fired up on a weekely basis regardless if you want it on or not, just to keep these nylon valve's lubricated etc....

your car ac clutch may be rooted/malfunctioning as someone else has stated or..check to c if its pulling in againts the belts when your mate turns the ac on..
sorry cant be more help,its been a long time since i looked under the bonnet of a magna

There should be a low-pressure sensor/relay on the compressor that won't turn on
unless there's enough gas pressure in the system.

Happened to me once - low on gas but still enough to ppsssst out the valve,
but not enough pressure to on the switch.

(can test by jumpering +ve to compressor clutch - ONLY if you know what you're doing)

Should the centre shaft of the compressor move back away from the belt when the AC is turned on? as Jared sugests

Ive found my multimeter so will now be able to suss it out better (at least the electrical parts)

I reckon its about 90% chance that its low on gas. Even when there's almost no gas you will still get some coming out of the valve when you press it in.

As said before, compressor wont work when its low on gas.

I just checked the plug going to the AC compressor. It is seeing 14 volts with the AC switched on and the motor running, and 0 volts with the ac switched off and the motor running.

To me this indicates that there is sufficent gas (the pressure switch isnt stopping it turn on) and that the problem lies within the the compressor.


The nylon valves that Jared mentioned, does anyone have more info on these? My Ac is run, if not daily at least once a week.

Is there something i can check to see if the magnetic clutch is actually trying to engage?