A/C compressor clutch doesn't engage

snakeye

Veteran Member
Joined
Dec 13, 2009
Location
Montreal, Canada
TDI
2003 Jetta and Wagon, GLS 5sp
I went to an auto ac repair shop, and they diagnosed and filled the system. They said the compressor needs to be replaced and said everything else works fine.

Now, I checked it out by turning the AC on/off, and nothing happens. The clutch doesn't engage at all. This leads me to believe that the compressor is fine, it's the clutch that needs repair.

Is there a way to test or remove the clutch without removing the entire compressor?

Btw I want to measure the voltage of the wire going to the compressor, but I'm a bit retarded when it comes to electricity. What do I measure, AC or DC?
 
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Dave_D

Veteran Member
Joined
Jun 9, 2003
Location
Gaithersburg, MD, USA
TDI
2015 Passat Titanium Beige six speed manual & Jetta, 1999.5, Tornado Red
AC clutch wiring is 12V DC. If you don't see voltage across the terminals with the A/C button in and the engine and fans running see if you show voltage to ground from one of the terminals. If you do you have a broken ground wire somewhere between the terminal and the ground connection. If you show no voltage at all start by checking for breaks in the wires or connectors from the clutch to the fan control module. Mine was broken at an intermediate connector.

Dave
 

snakeye

Veteran Member
Joined
Dec 13, 2009
Location
Montreal, Canada
TDI
2003 Jetta and Wagon, GLS 5sp
Thanks for the reply. I checked for 12 volts, and I got 9.21 when the car was off, running, and with the AC on, except that when the AC was on, it kept jumping to around 12v every 5-10 seconds. Is that what it's supposed to do?
 

TOBarber

Veteran Member
Joined
Dec 20, 2002
Location
Toronto, Canada
TDI
Golf SportWagon, 2012, dark gray
Thanks for the reply. I checked for 12 volts, and I got 9.21 when the car was off, running, and with the AC on, except that when the AC was on, it kept jumping to around 12v every 5-10 seconds. Is that what it's supposed to do?
Yes, it wants to start but doesn't see the proper pressure so shuts off for a bit, then tries to start again.

On my '00 Golf TDI automatic, the clutch was shot. You can take out 2 bolts and drop down the compressor without breaking open the AC. There is 1 connector for the wiring. I bought a replacement clutch on eBay and replaced my clutch... still working fine. The only catch is that there is a C-clip that is just too deep for my standard pliers to reach, so I had to take apart the pliers and use needle nose pliers on the C-clip head to remove and install the C-clip. Maybe you can find a better (narrower) C-clip pliers. I vaguely recall some pictures over on the Vortex site.

When I tested the clutch coil wiring, it was open circuit.
 
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snakeye

Veteran Member
Joined
Dec 13, 2009
Location
Montreal, Canada
TDI
2003 Jetta and Wagon, GLS 5sp
Oh god... c-clips are good for ruining perfectly good days. Let's hope it's not that hard to remove. Thanks!
 
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