Thread: air con problems,

btw ive searched and found no soluition

pop the covers off the fuse and relay covers and the answers will be there.

after youve confirmed your relays and fuses are working find the reciver drier (black canister with 2 pipes and an electrical connection to a switch on or near it) remove the lead from the switch and fire up the engine and the aircon then short out the plug. If that starts the aircon then the pressure switch has died and needs replacing. You shouldnt run without one as it stops you from running the compressor dry BUT you can bypass it in a pinch to keep it working.

Assuming its not that break out the meter or the test lamp and start tracking down the voltages.

ok what relay should i be checking, theres one for the ac fan, i know thats working, all fuses are not blown

wheres the black canistor?

and what u mean short the swich( the one at the compressor)?


i just seam to be not getting power to the compressor to enagage it

the reciver drier looks like this



it will be connected to 2 aluminum pipes.

near or attached to it will be a switch which will look likes

that or more likelythat.

remove the plug from that switch and check that plug for voltages. if its got voltage try shorting the 2 pins in the plug with a jumper wire and see what happens, if the aircon starts then the pressure switch is faulty. If there is voltage at that plug an shorting it out doesnt make the aircon work then the problem lies elsewhere in the electrics of the aircon itself.

thanks for the quick reply, ive just dragged the missus out to look for the recieiver drier, maybe it could be mounted at the front behind the grill as we cant find anything like that under the bonnet

but i did find a ac pipe with a plug very similar to the one pictured, its near like a fill up valve, on the drivers side could this be it??

it could be.

its been a while since Ive had to do aircon on a Disco, but since the swmbo now drives one I can go and eyeball that if you need me to. what colour cap is on the plug? if its red then yes that is the switch, if its missing the plug then follow the lines if it is mounted to the same line as the Reciver drier odds on its the right switch to have a play with.

the flow of the aircon gas (very quickly)

goes from the compressor to the condensor into the receiver drier, into the TX valve into the evaporator and from the evaporator into the compressor.

the cut off switch can be anywhere between the compressor and the TX valve.

thanks for your help, i cant see much tonight, but the swich /plug(on the ac pipeline) i was talking about was closer to the brake master cyl(and didnt have a red cap, just a : H),
i didnt locate one on the reciever dry which was located behind the grill, i followed the ac lines and could only see 1 plug as mentioned above .

what yr/model is ur d1?

im thinking about just hard wiring with a fuse and seperate switch just to get the ac running and hope this will do for summer this year.

do u reakon will it cause any damage as i dont want to be spending 100$ at a auto electrican( at this time of yr)

yep if you hard wire the compressor on and you dont have enough heat load on the evaporator the TX valve will read too cold and close off flow, the compressor wont turn off and at a minimum you will burn up the belt and seals on the compressor. Worst case you will cause a liquid lock in the compressor (rare but it does happen in systems that are overgassed) or run the system presure up so high it ruptures something (normally the condensor).

bypassing the switch is a diagnostics/short term thing only.

if the switch is in the line that is capped with a H then its the right one to play with.

my advise if you dont want to pay to fix it..

live with out it, its only aircon and your disco has windows.