Welcome to BigCarClub!

Not logged in!

Hey there, welcome to BigCarClub!
You don't need to be logged in to view the forum but the experience will be so much better if you are! Users can login or if you don't have an account already, you can create one for free by clicking the Register link in the top right corner of this page.


Aircon pressure switch wiring

Started by JR Watchet, August 11, 2022, 11:49:45 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Long time no post and surprised to see the change to Big Car Club!

I have 2 x Galaxy Mk 2 2005/6 with aircon issues.   One has error code "intermittent short to ground" and fully gassed aircon wil not pull in clutch.   I have a spare switch from another scrap car, but doesn't look if I can get it off without damaging pipework, so need to bypass the switch for now.

Wiring diagram i have shows a changoever switch with only 2 pins used, but loom on car has 3 wires to sensor (black, brown, yellow/red)

Part is a PT4-H1001-1
1J0 959 126 DRH

But can't find data here or anywhere online!!!

Not yet looked at plug etc on faulty car as need to get wheel arch off to check it and possible front bumper, but does anyone know the connections and function of the switch - is it passive or a pulse sensor for example


Hey John, welcome back!  :welcome3:

That three pin sensor is the pressure sensor, it detects both low pressure and high pressure conditions in the system (Hence the three pins) - one ground and two outputs.

Typical VW wiring would have the ground in the centre and the two outputs either side but that's just a guess, I suspect you'll also find it's a simple on/off switch depending on if the condition is met.
03 Ford Galaxy 1.9 TDI 115 Ghia in Spruce Green Metallic
With cream leather interior, Full Bodykit, Remapped at 145bhp, Lowered on 18's
17 Volkswagen Touareg 3.0 V6 Diesel in Slate Blue
262Bhp AWD and Factory fresh...for now!
58 Ford Transit 2.2 TDI 115 in Frozen White
With retrofitted everything except another slidey door! :)
LAUNCH X431 Pad PRO - Scanning & Coding for all makes and models done in Wiltshire in exchange for winegums! :)