Aircon High Pressure Switch Replacement

**nevo** · 20-08-2011,09:57 PM

Jim if your fans not kicking in your compressors not functioning,you can check by observing the front plate on the pulley should spin with the pulley when the clutch is energised,by the way who did your regas?

**jim_tdi** · 21-08-2011,07:35 AM

The compressor is definately not engaging. A local garage did the regas. I suppose next step is getting compressor changed, which means money. Could be the end of the A4...

**nevo** · 21-08-2011,10:38 AM

Check you've got voltage at the clutch when the aircons on,no voltage means the comps not being asked to start.

**jim_tdi** · 21-08-2011,11:52 AM

If I look down from the front of the car, the compressor is on the left below the condensor fan? It's hard to see whats down there without removing a lot of stuff.

I can't see any wires going to the compressor so I'll need to remove some of the pipes to get a voltage reader in.

Is the compressor replacement job a front of car off job?

**nevo** · 21-08-2011,12:15 PM

No ,just jack the front up and take the undertray off.

**jim_tdi** · 21-08-2011,12:37 PM

Thanks. Assume that's the easiest way to check the voltage as well?

**nevo** · 21-08-2011,01:29 PM

Yes,before you condemn the comp,check the easy things first,if there's voltage there it could be the clutch inop,if no voltage run a fused line from the battery to it and see if it works(engine off)also talking about easy things have you checked the fuse,do a continuity check across the blades, not visual!also check inside the fuse holder make sure some ham fisted git hasn't bent anything.

**jim_tdi** · 21-08-2011,02:09 PM

First thing I did was check the fuses -1 and 6 I think are AC fuses. They looked fine. I then got the regas done which showed no leaks are pressure problems. Next was VAGCOM showing the high pressure switch dead, so I replaced that and the error cleared.

That's where I am. I'll prob have to let and indie garage have a look.

**fla** · 22-08-2011,12:08 PM

The compressor is basically a mechanical devise so there's not much to 'go wrong' as such. I've just bought new clutch for mine, which is premetive as i havent even checked power to it yet!..You're doing the right things though and nce you can establish power to the compressor is ok, the next step is to check that the clutch is not slipping or the front plate is not loose.

I took mine to a local indie garage and they were charging around £500 to replace the compressor, which is a bit out of my budget tbh.

**jim_tdi** · 22-08-2011,12:15 PM

I've had quotes much the same. I have found a place that supply second hand compressors for £105 delivered with 90 days warranty. Prior to that, I am going to pop the engine cover off the bottom and just check the clutch - maybe it's something simple like the plate has fallen off. Probably not, but worth a look.

Few quotes so far to fit replacement compressor and regas £150 ish which would mean around £250 all in. Quite annoying if truth be told, as this is one of those jobs where I guess you really need an aircon gaser, which I don't have !!