2001 Eurovan AC clutch not getting power

[PtownVdub]

I have a 2001 Eurovan MV tintop with climatronic. I am attempting to diagnose why the air compressor will not engage.

What I have done so far:
- New air compressor and clutch (installed by previous owner)
- Evacuated the system and recharged it by putting 12v to the ac clutch (clutch engages and the compressor runs)
- New trinary switch
- Verified that the ac clutch has a good ground connection
- Verified that the radiator fans turn on when climatronic is in auto and temp is all the way down
- Verified that jumping 3 - 4 pins on the trinary switch connector turns on the fans

So the problem is that the ac clutch is not getting 12v and therefore is not engaging. Short of taking it to the dealership, I have run out ideas to diagnose the system. Any ideas or a wiring diagram would be greatly appreciated.

Thanks in advance!
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2001 Eurovan MV - 2.8L 24v, 4 speed automatic

[Joshwa]

Do the fans run when you switch the AC on? I'm having an issue where my fans don't even want to run due to not enough pressure. When I jump the pressure switch, they come on, but the compressor doesn't engage. I have tried testing for 12v at the compressor, but I'll try that next.

This is a complicated system, and with your climatronic, it's probably even a little more than my mechanically actuated system. I was asking about the fans running as it is a requirement in a way for the compressor to engage. For the fans to run, there are a series of sensors that have to pass to have continuity.

In order for the clutch to get power, the AC must be switched on and fan circuit running. For the fan circuit to run, it must have continuity through a shutoff controlled by relay, shutoff controlled by temperature, AC pressure switch, and evap temp switch. An Easy check is to see if you have 12v at the pressure switch, and if you have continuity through the pressure switch. From there you would need to see if you have 12 at the relay in the fuse block. That's where the 12v would be going out to the compressor from as well.

I have a poorly phone shot wiring diagram for 98+, but you'll have to pm me your email address to be able to send to you. It's 15meg. AC starts on diagram 76/1.
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93 Weekender TDI conversion (AHU)
93 MV TDI conversion (1Z)
Weekender rear cot
Late model cabin air filter on 93
Euro spec bumper install on 93

[TDCTDI]

See if your coolant after-run pump is working. These were notorious for failing & blowing the fuse that also controls the cooling fan relay which has the final say as to whether or not the compressor gets power.
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[PtownVdub]

Thanks for the ideas.

My radiator fans turn on as soon as I turn on the air conditioning ("auto" and max cold) on the climatronic. This tells me that the system has enough pressure, the trinary switch is working, and the fan control module is working.

Tonight I will check to see if I have 12v at the AC trinary pressure switch (I am guessing that either pin 1 or 2 on the connector carry 12v to the pressure switch). I will also check for continuity through the switch but the switch is new so I hope it is working.

I had not even thought to look for a relay under the dash for the AC system but that makes sense. It appears that the relay is labelled 140. Is that correct? I will dig around and make sure it has 12v as well.

Thanks again!
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2001 Eurovan MV - 2.8L 24v, 4 speed automatic