A/C troubleshooting guide

Would anyone happen to have an A/C troubleshooting guide?


My A/C is not working. Turning on the A/C switch does nothing, no load on the engine. The fuse is not blow. Just need a little direction.


Thanks,


Jesse

I got out my Vag-Com and I do have a fault code: (9481200 - Refrigerant Pressure) B10AB F0 [009] - Too Low.


What I found really odd is I'm not getting any results on the compressor

There is no Freon in the system so the compressor won’t kick in. Go get Freon and refill it. Get one with sealer and UV light one so that you can track down where it leaked out

Like most all modern cars, it likely left the factory with dye already in it.

I have not seen any NMS Passats yet with a refrigerant leak, so I couldn't tell you where a common place is to look. But do a visual check over of everything you can see first. You might see an oily spot where it leaked out if it has not been too terribly long.

I'd also want to verify the system is truly empty. A quick press on one of the service ports would confirm this.

-J

Yeah...modern cars have a low-pressure cutoff switch. If there's not enough freon (yeah, I know), then you can't damage the compressor by running it on a low system.

It may not be empty: just low. Or, a bad low-pressure cutoff sensor.

Strider17 said:

There is no Freon in the system so the compressor won’t kick in. Go get Freon and refill it. Get one with sealer and UV light one so that you can track down where it leaked out

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Please don't do this, get an off-the-shelf "refill" kit.

HVAC systems are sealed systems, which should never need "refilling". The R134a in these does not "wear out" or need "topped off". If the refrigerant gas has indeed leaked out, there is a more serious issue at hand, and any "sealant" that may be in the can is a temporary fix at best, and will almost certainly cause damage that could have been avoided if you had taken it to a qualified HVAC tech to diagnose and properly repair. Also, there is a specific quantity of compressor oil required for different compressors, and those cans have no way of knowing what they're being installed in, and take a "one size fits all" approach to oiling.

Off-the-shelf kits are ok if you're driving a '98 Kia that's falling apart anyway. But if you plan on keeping the car for any length of time, your best bet is to get it serviced by a qualified tech.

c3kTDi said:

Yeah...modern cars have a low-pressure cutoff switch. .

Click to expand...

VW has been using pressure sensors in their AC systems since 2000.

My 99.5, and old Benz do have on / off pressure switches.

-J