By Steve Schaeber, MACS Technical Editor
Technicians working on a third generation Jetta might find their A/C controls totally inop, including no blower fan operation amongst any of the fan speeds, and no operation of the A/C button or recirc button. Even the backlights behind these buttons may not illuminate. A possible cause could be similar to what was found on this 1999 Jetta here at the MACS Garage a few weeks ago.
Photo 1: Operator’s control panel for this ’99 Jetta has ON/OFF buttons for both AC and Recirc.
Fuse # 25 is listed as the “Fresh Air Blower, Climatronic, A/C” fuse, but actually powers most of the A/C control panel as well. When this car came into the shop, the “AC” button on the controls would not light up when depressed. Since the vehicle was recently in for service, and the system was known to be in good working condition, I figured it had to be something other than the mechanical refrigeration circuits. I went right after the fuse panel in the driver’s door jamb to inspect the fuses.
Photo 2: The cabin fuse panel on the Jetta can be found by opening the driver’s door and removing the access cover.
Before going all out and testing every fuse in the panel, I decided to look up the fuse function arrangement in my service information system. When I found the right chart, I printed out those pages, and using a yellow highlighter, marked all the fuses related to the A/C system. That way, when I took the pages out to the shop to start my testing, I knew exactly which ones to look for. I even highlighted their colors and positions in the panel to make identification easier. The nice thing about taking this extra step is that you can save time by not testing unrelated fuses, and go right to the potential problem areas.
Photo 3: A yellow highlighter indicating the fuses to test makes the job easier out in the shop.
Turns out that fuse # 25 was the culprit, and a new fuse took care of this problem. The vehicle owner was happy to again have a working blower motor, not so much for use with the A/C system (2014 has given us a rather mild August), but primarily because of the potential safety issue surrounding an inoperable windshield defogger. It’s still working in this daily driver now, all these weeks later, so we’ll call this one fixed.
Have a similar repair you’d like to share with MACS? Drop me a line to email@example.com and share your story.
If you’re a service professional and not a MACS member yet, you should be! Become a member and receive a monthly technical newsletter with information like what you’ve just read in this blog post and much more visit http://bit.ly/10zvMYg for more information.
You can E-mail us at firstname.lastname@example.org . To locate a Mobile Air Conditioning Society member repair shop in your area. Click here to find out more about your car’s mobile A/C and engine cooling system.
Mobile A/C professionals should plan to attend 35th annual Mobile Air Conditioning Society (MACS) Worldwide Training Conference and Trade Show, Meet me at MACS Make Connections that Matter, February 5-7, 2015 at the Caribe Royale, Orlando, FL.