Thread: Air Con tri switch test?

Have you tried the aircon relay?

Ist thing I did was put in a known good spare. I then jumped direct across the relay terminals which I thought would make the compressor run regardless. No joy. This is why I want to test the tri switch as my understanding is it makes and breaks the circuit ( I might be wrong)

the Tri switch controls the relay....

if yiou cant get it to run by jumping the relay then the problem is in the main feed to the relay or the connection from the relay to the compressor.

the simple way of eliminating the tri switch is to test it for continuity. if its open circuit then its either broken or low on gas (or way over pressure) if when you put 12v directly on the compressor with the vent fans on you get cold air out of the vents then its not out of gas.

If the tri switch is working and it's way over pressure then your condensor fans will be on high.

I have started again from scratch. Checked the Relay OK, Checked 12v at fusbox ok. Checked continuity fusebox to compressor OK. Realised i jumped the wrong terminals on the fusebox before, Got it right this time and compressor kicks in and icy cold air floods into the cabin

So Relay good, fused 12v supply good, Comp Good, Gas I presume plenty.
If the pressure switch controls the relay can I jump that safely.
Should I get 12v somewhere at the Pressure switch?
What makes the compressor cut in and out, is it an internal switch. Can I jump the relay safely until I find the problem?
Can I just unscrew the switch. I read you could as there was a valve behind but don`t want to put the switch into orbit.
I want to be prepared as it looks like the bumper has to be removed for good access.

Do you have some gauges you can throw on it ... I've only worked on a couple of cars, but the ones I have had a shrader valve behind the switch, so in theory you can unscrew them without releasing all the refrigerant............ However I am willing to post the switch back if it lands in Ballarat

if it's low on refrigerant it might be dropping the low pressure switch out (I think I have that right). it's hard to tell anything without a manifold/gauge set.

seeya,
Shane L.

I am presuming that the gas pressure is fine as the Shop that did the work has commented that the system is fine but specialist Land Rover investigation/ diagnostics required.

Originally Posted by wayneg

I have started again from scratch. Checked the Relay OK, Checked 12v at fusbox ok. Checked continuity fusebox to compressor OK. Realised i jumped the wrong terminals on the fusebox before, Got it right this time and compressor kicks in and icy cold air floods into the cabin

So Relay good, fused 12v supply good, Comp Good, Gas I presume plenty.
If the pressure switch controls the relay can I jump that safely.
Should I get 12v somewhere at the Pressure switch?
What makes the compressor cut in and out, is it an internal switch. Can I jump the relay safely until I find the problem?
Can I just unscrew the switch. I read you could as there was a valve behind but don`t want to put the switch into orbit.
I want to be prepared as it looks like the bumper has to be removed for good access.

no becasue the relay also has inputs and controls from the AC thermister, the ac switching/brains, the over heating engine turn off ac control and the 3 way pressure switch.

if you jump it on permanantly it will ice up the evaporator and then keep on going till you liquid lock the compressor.