My air con is not working.it has gas in the system,relay is ok,air con switch is ok but the air con compressor does not turn on when air con is on.when you direct the compressor or brigde the relay,the compressor turns on and the air con works. the air con fan does not work as well.

The system is low on Freon ,you have cut out presser switch this will stop the compressor to turn on ,add Freon and the compressor will pump gas ,all the best.

There are several switches involved in an ac system . There is a high pressure switch that turns off the compressor if the head pressure is too high (blocked system-excessive gas qty) and a low pressure switch that switches off the compressor when there is insufficient gas -(leaking system)/ Next some systems do not work unless the blower and the ac switch are both on ( prevents ice forming on the evaporator coils from lack of air flow ). That is the electrical side of things . Next there is a TX valve that allows the liquid refrigerant to become gas in the evaporator ( producing the cold air) that can become blocked . There is a thermostat that is attached to the evaporator fins that will shut off the ac compressor when the cabin temperature has been reached. Next there is an air/dryer accumulator that can become blocked from moisture and dirty oil that will affect the operation. Well that is all the points that can cause problems.
How does it work . The system is full of refrigerant gas that boils off at a very low ambient temperature . The compressor compresses this gas and turns it into a liquid refrigerant in the condenser (In front of the radiator ) This liquid is pumped to the TX valve which releases the liquid into the evaporator coil and as this area is in vacuum from the compressor sucking the gas ,the liquid going from a liquid into a vacuum boils off from the heat in the car . This cools the air in the car . The gas is then sucked back to the compressor where it is again converted back to a liquid . As you can see ,any items that are not working properly will cause problems because the circulation of the gas has to follow a set procedure or the compressor will shut down. Best advice is -if you having ac problems then take it to an accredited ac specialist and have the system tested for gas and leaks.

The only other thing then would be if the compressor is turning, engaging, and the cooling fan working properly. You should either be able to see the compressor clutch engage, as the switch is energized, or at least hear it click loudly when the switch is energized. If it is not, then there are sensors for the low pressure/high pressure line to tell the compressor when to function, that also have to be checked.

As the engine runs with the compressor turning, one line should be hot/warm, the othe,r (larger diameter hose) should be cool/cold, if the system is working properly.

If the compressor is turning when you have the A/C turned on, then see if the cooling fan is running as well. It must run to remove the heat and cause the process to function properly.

Good luck!

There could be few problems, if the gas is too low or too high the compressor will not work, maybe the compressor clutch is not engaging. why don't you power the compressor from the relay and see if the compressor works or not.

When you have a moment pop the bonnet and look for the air con compressor run by a automotive belt on the side of the engine. Get the engine running at idle and then get someone else to turn the air con on whilst you watch the compressor. As the system is turned on the compressor clutch should engage and the unit should start turning, if this isn't happening there isn't enough pressure in the system (leak or just low on pressure) Get to your local air con guy and they will pressure test for leaks. Air con system is run on pressure, so that is really the issue you need to rectify

Note:- Manufacturers put the air con rad infront of the engine rad so stones get to that first, check the condition of the front rad through your bumper

Hi:

You should verify that your AC system still has a full charge of refridgerant, and if it does,
The problem is most likely the AC clutch assembly on the front of the compressor.

Since the dash light works, and the fan turns on, there is power to the system, but the compressor won't turn on if the pressure switch says the charge is low, and if you turn the switch, and someone can hear a click of the compressor clutch solenoid, but no air, the clutch assembly is probably the culprit

Do not play with this vehicle,if AC not working then take to a dealer or someone who understands jags ,these systems use a lot of complicated sensors and pressure detectors ,and they always leak gas and need rechecking once a year .The pipes go porous,the O ring seals play up and often the thing will just dump the gas out of the compressor for no obvious reason ,except to us that repair them ,its caused by the fan not coming on when the AC is turned on and it builds up too much pressure and ,this is caused when one of the these pressure sensors switches play up

Hi all air-con system have a tririster switch usually screwed into the pipe near the aircon radiator or Drier (Cylinder shape near Rad) these are known for failing and will kill the circuit to the compressor its there to make sure the compressor does`nt run with no gas in it,get a wiring diagram and bridge it, will be 2 of the 3/4 wires going to the switch,but yes check the wiring as well.
Darren

the missing part could be the cover... its ok , not cooling very well could be:-
1, aircon fan not working
2, system need to be service
3, need to add air-con gas

for air-con works only in full position.... need to change the switch.. its faulty.

a/c module. near fan shroud, early models had it behind glove box.