AC Troubleshooting Tips

2003 VW Jetta TDI

What are some tips/steps for doing basic AC Troubleshooting?

Sometimes the AC cools really well and other times it does not cool at all. I checked the charge (suctions pressure with the AC On) recently and it was OK.

Thanks in Advance.

Single gauge does not tell you much.

need high and low side gauge.

also need a VCDS, which will give you more insight into what is going on

(others with an 03 can provide specific readings available)

You can go to the A4 Forum and look at the Sticky.

One thing is to check is if the radiator fans are working. I know from personal experience that with both fans working correctly, you get cool air all the time. With only one working, the air got slightly warmer when stuck in traffic and cooled down on the highway. When both failed, I got cool air on the freeway, but once I hit traffic the air got warmer and warmer and was useless in very short order.

Quick test: engine off, key on ON position, fan switch on 1, AC button pushed in and lit up. Both radiator fans should be running on low speed. If not, you've got one or more bad fans.

Testing the high speed setting and other fan-related test are here: http://pics.tdiclub.com/data/516/A4_Coolant_Fan_testing_Rev_7.pdf