Technical Air con think electrical issue

[Westies on tour]

Hi,
Please help.
Had my air con re-gassed today and its now good gas wise.

But still not working, clutch not spinning
I have done some checks and I have no power to the compressor.

I did a test with some wire direct to the compressor via battery and it DID work.

I do have power to the relay and fuse.
So I'm now thinking maybe a damaged wiring harness some where around the engine ?.

Has anyone excess to any wiring circuits you maybe able to help me please.

Need to know where the wires go from ac compressor to the fuse box need the colours .
As i cannot see anything as the wires go into the engine.

Any advice would really help
Thank you.

Jason.

 

[oldmanhouse]

If the system definitely has pressure (not under or over pressured) then maybe check the pressure sensor, down near the condenser behind front bumper. If that is faulty that may explain it. Really the garage doing the AC service should have checked the system was working before adding refrigerant

 

[Baglady1990]

Why on earth has a garage re gassed your a/c and not checked it’s working!!? I had mine re gassed a year or so ago & they obviously checked for pressure & had the system running after gassing … isn’t that normal operation?

 

[John202020]

Why on earth has a garage re gassed your a/c and not checked it’s working!!? I had mine re gassed a year or so ago & they obviously checked for pressure & had the system running after gassing … isn’t that normal operation?

Well, if it was empty or under pressure you could assume its working but tripped out ? Therefore refilling a otherwise good system should restore it, however they should have said its been refilled but still not working.

Do the cooling fans run when ac on but not compressor or is it dead, try the pressure switch otherwise contact a ac professional they will be far faster at locating the issue.

When did the ac last work correctly?

 

[A3jeroen]

Had this on my Stilo a few years ago. System vacuumed, regassed and it was perfectly cold... Just once. Checked with MES and I could switch the AC clutch on, but the faultcode was too high pressure. Got myself a new sensor, switched it and it worked perfectly again.

gr J

 

[John202020]

Had this on my Stilo a few years ago. System vacuumed, regassed and it was perfectly cold... Just once. Checked with MES and I could switch the AC clutch on, but the faultcode was too high pressure. Got myself a new sensor, switched it and it worked perfectly again.

gr J

Can you replace the sensor when the system is pressurised ?

 

[A3jeroen]

Can you replace the sensor when the system is pressurised ?

There is a Schräder valve behind it, so if you get ot out quick enough, you don't loose refrigerant.

gr J

 

[John202020]

Before replacing the sensor check the system is not over pressure? It's a simple pressure switch so either open or closed so you could override it to see if it is at fault?

 

[Westies on tour]

Hi all,
There's no power to the air con compressor but is the the fuse and relay, so this is telling me theres a damaged wire between theses.

The compressor does work as I put a 12 volt live feed to it and it starts to spin at the compressor.

Does anyone know the 2 wires from the compressor where do they go as I cannot trace the wires as they go into the rear of the engine.

 

[John202020]

Hi all,
There's no power to the air con compressor but is the the fuse and relay, so this is telling me theres a damaged wire between theses.

The compressor does work as I put a 12 volt live feed to it and it starts to spin at the compressor.

Does anyone know the 2 wires from the compressor where do they go as I cannot trace the wires as they go into the rear of the engine.

It's more likely that there's a control issue, rather than a broken wire, if the system has a fault or is over pressure then no signal will be sent to prevent damage?
Check fuse 19 and relay 5 also fuse 51 inside the car, 36, 31, interestingly the Haynes diagram doesn't show the compressor clutch feed

 

[Farrah]

So many times I read how when testing circuits people say I have 'POWER' just because a meter is reading 12vdc.........a 12vdc reading on a digital meter just means you have the potential of 12v..............check output at the relay to the compressor with a load, even a simple 12v lamp before assuming a break in the harness unless you can show from point to point along the harness you have lost continuity between each end of the wire

 

[John202020]

So many times I read how when testing circuits people say I have 'POWER' just because a meter is reading 12vdc.........a 12vdc reading on a digital meter just means you have the potential of 12v..............check output at the relay to the compressor with a load, even a simple 12v lamp before assuming a break in the harness unless you can show from point to point along the harness you have lost continuity between each end of the wire

I will add just because you have power on a digital meter doesn't mean you have current , and remember it's sometimes switched on the earth side?

 

[The Panda Nut]

May be also check the switch for the aircon is actually working.