A/C cut off relay

[njt1rider]

So I sold my tdi swapped 93 weekender. I never got around to diagnosing why the a/c didn't work. I lived in it for 3 years with no a/c . Talking to the new owner today I was trying to help him solve the issue. Open up the bentley and within 5 minutes I find that there is a clutch cutoff relay on the auto van that isn't present with a manual. It appears that the relay just needs to be removed and hardwire the clutch wires per the schematic. Doh! Feel pretty silly now but here's my question:

Why do the autos have an a/c cut off relay that gets a signal from the tcm and the manuals just don't have the relay?

[Abscate]

You don't have a TCM in a manual and Germany was too busy cheating on emissions to develop an ECM output to do the same.

(sarcasm) but probably the reason why.

It is a bit weird to have the AC cutout by the TCM - all other makes Ive worked on have the ECM cutout
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.ssS!

[Zeitgeist 13]

That's a weird one. The T3 uses refrigerant pressure/temperature switch(es) for the clutch cutout function and only ties the A/C system to engine management via the idle control relay...and perhaps the TPS under WOT conditions. Maybe the T4 autos use clutch cutout when the driver manually downshifts under WOT conditions.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Abscate]

I’ll look in my turbo beetle stick diagram to see if it’s a VAG thing

My Beetle is a very masculine dark blue, so it’s not a girl car.

My girl car diagram shows the AC clutch is controlled by the cooling group relay, which receives mutiple inputs from ECM and other sensors.

So, no TCM to cut out relay there.
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.ssS!

[Broseph Stalin]

[Zeitgeist 13]

I see the early T4s use a nearly identical pressure/temp switch as my T3. This could very well be your culprit.

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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Broseph Stalin]

[njt1rider]

The cut off relay is in position number 30. Sounds like you need to do some general troubleshooting before throwing random parts at it. (Much cheaper)

[njt1rider]

That pressure switch is on the a/c hardlines coming out of the firewall on the passenger side under the hood

[Broseph Stalin]

[njt1rider]

There are a series of switches the signal needs to go through before it hits the clutch. The cut off relay is only one of them. PM me your email address and I'll send you the schematic. Tracing the wires are only half the problem as you will need to check that all the switches are working at the proper pressures including the relay and a/c module. The first thing I would do is jump the wires at the trinary pressure switch and see if the clutch turns on and the system blows cold air. If you have that then I would say there is a problem with the relay/control module/ switch/ or broken wire.

[MasterMarine]

I am not getting 12 v at my compressor clutch on my 2002 VW EV. I do not have the Climatronic. It is a Weekender. Does anyone have the wiring diagram? I have the Bentley but can't access it since I don't have an operational XP computer anymore.

Fuse is good. Relay 140 looks good inside for me.

Any tips? Wiring diagram?
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MasterMarine
2002 VW MV Weekender
2004 VW Jetta GLS TDI

[MasterMarine]