Help me fix the A/C in my VW Golf TDI
August 5, 2010 6:08 PM   Subscribe

My air conditioning suddenly conked out on my 2002 Volkswagen Golf TDI (diesel). The mechanics at the dealership are having trouble finding the cause and I'm spending a lot of money on diagnostics, with no definitive end in sight. It's hot here in Toronto - help.

The mechanic at the dealership has told me that the compressor is fine and that they tried to replace other parts (i.e. the fan system), but to no avail - the cooling fans simply won't run, even when they ran the car so it got hot (which takes awhile for a diesel) - so they are down to searching for bad wiring. My dilemma is this - how long does one allow for a diagnostic search to take place? When do you call it quits? I'm about to start hour three at $100 per hour. What if I spend $600 on labour time and they never find out what's wrong?
posted by analog to Travel & Transportation (14 answers total) 2 users marked this as a favorite
Maybe I'm missing something huge here, but before they changed the fan, they should have checked whether the fan(s) were getting power or not. A few minutes with a volt meter would have told them whether the fan was getting power or not.

Ask them if they checked that. And if they checked the fuses and relays. "Bad wiring" is the last thing to check, after checking all the control circuits.

Here is what they should be doing:
1- Check for power at fans.
2- Check for power at the relay.
3- Check for signal at the relay.

They should have a diagnostic computer that they can hook up to the car to tell the computer to signal the fans on. If that works, but the fan doesn't work when the AC is turned on or when the car heats up, something weird is going on. It *could* be bad wires, but it is just as likely two things went bad simultaneously. That computer should also be able to report the coolant temperature that the computer sees, and they should compare that to an actual thermometer reading. If it is wrong, the coolant temp sensor is bad. The diagnostic computer should also be able to report whether the computer "sees" when you have turned the AC on. If it doesn't see that, it won't turn the fans on because it doesn't think it is supposed to. They should check the hvac switches. They can also do all of these checks with a multimeter, but it takes longer. Either way, it shouldn't take more than three hours to trace all of these circuits down.

They sound like they are either morons, or taking you for a ride. Don't pay for the fan(s).
posted by gjc at 6:43 PM on August 5, 2010

"Bad wiring," huh? If I were feeling snarky I'd ask if they have any internets at the dealership.

What if I spend $600 on labour time and they never find out what's wrong?

You call VW of America and ask them the same question:

U.S Hours are 8:00 am — 10:00 pm EST Mon — Fri

You're getting the runaround, your car isn't exotic. Even if you don't call VWOA, if the above fixes things you should find the dealership's manager and ask him why you should pay more than one hour's labor for that fix.

I'd also run this past the cats in the Jetta TDI forum for '02s at vwvortex.
posted by rhizome at 7:19 PM on August 5, 2010

I don't know about Canada, but in the US it's illegal for a mechanic to just start replacing parts in an attempt to find the problem (These scammers are known as "parts replacers".) Meaning...if he or she replaces the fan and it doesn't fix the issue, you don't have to pay for the fan. Any good shop will refund your money if the new part doesn't fix the issue.

My first recommendation would be to get you car out of there. Dealerships are always over priced and they don't offer better service like many people believe. Find a reputable local shop. More than likely, they won't charge you a dime to find out the root problem. It's called a free estimate and any shop that prides itself with good mechanics will offer one.
posted by WhiteWhale at 7:37 PM on August 5, 2010

Response by poster: Thanks for these great responses - I should clarify that they tried new fans, but as they didn't power on, either, they did not leave them in - I think they were using them as a diagnostic tool? (maybe I'm being too nice?) As it stands right now, they haven't charged me for any new parts - just labour to diagnose.
posted by analog at 7:43 PM on August 5, 2010

I just did a quick search online and it looks like one or two of your fuses on top of the battery are likely melted. If that's not it check the fan control module below the battery.

That will be $300... :)
posted by WhiteWhale at 7:43 PM on August 5, 2010

And if you end up getting a bill for $300 to change some fuses, you should get on the phone with the BBB, VW of America, your lawyer, and anyone that will listen.
posted by WhiteWhale at 7:58 PM on August 5, 2010

"Bad wiring," huh? If I were feeling snarky I'd ask if they have any internets at the dealership.

Except that it's a Jetta and they have notoriously shitty wiring. My entire dashboard? melted due to the shitty wiring. On the mid 90s models it was common to just replace it all to avoid these kinds of repeated fishing expeditions.
posted by fshgrl at 10:05 PM on August 5, 2010

Never, ever, ever, ever take your car to a dealership if it's out of warranty. Go to enthusiast forums, get recommendations for local repair places with good reputations, and get advice from other folks who've likely had the same problem. If you can't get a recommendation, look for a small hole-in-the-wall german car garage that looks like crap but always seems to have tons of old Porsches being worked on.

Case in point: I had an '85 Jetta that kept running hot, and I couldn't figure out why. Got an estimate from the dealer in the hundreds, said fuck that. I got a recommendation from a friend for a local place, and while heading there, found the wrong place, a hole in the wall with Porsches et al. Not realizing my mistake, I went in, and described the problem. He stopped me, said "I know what it is, $20" in broken english, and sure enough he replaced a $20 part and off I went with a nice cool car about an hour later.

Since then (until I stopped owning German cars because of all the little problems that crop up) I always went for the places stuffed with Porsches (if the car I needed fixed was water cooled) or old veedubs (if air cooled) and never had a problem.
posted by davejay at 10:24 PM on August 5, 2010

Response by poster: Just heard from the dealer - WhiteWhale was right - the fuse box had melted and a fuse had also blown. I was told that for some reason my fans seem to draw a lot of current and they'd recommend replacing them in case this happens again in the future - but that's an extra $775 I don't have right now, so I'll take my chances.
Three hours to diagnose a fusebox and fuse problem does seem like a long time.
Thanks to everyone who replied - all good advice.
posted by analog at 6:45 AM on August 6, 2010

I am shocked that they expect you to pay several hundred dollars for their diagnostic attempts to resolve an issue they thought might be electrically caused, and for which they didn't check the fusebox first. I'd call VW of America.
posted by MonsieurBon at 9:30 AM on August 6, 2010

Jesus Christ, they really really want you to buy those fans, huh? There is no "for some reason," your car has the same fans as every other Jetta that doesn't have A/C problems. Don't these people have a voltmeter that they can use to measure the current drawn by the fans? I'd actually ask them that, and to describe how the observed voltage differs from the spec.

Seriously, if this was really a case of LOLVW, there would have been a recall. I have a more recent VW and I've had recalls for extremely minor things, so melting fuseboxes would seem to be a rarity. Not that this shop shouldn't have found it in the first 30min, like MonsieurBon says.
posted by rhizome at 12:53 PM on August 6, 2010

Details per WhiteWhale.
posted by rhizome at 12:54 PM on August 6, 2010

I just did a quick search online and it looks like one or two of your fuses on top of the battery are likely melted.

That's an EXTREMELY COMMON KNOWN PROBLEM on that car. You can't walk down the street without tripping over a Golf, Beetle, Jetta, or Audi TT that's melted its fuse panel at some point. I think there may even be a TSB for it. Anyone who's worked on even a handful of VWs should KNOW IMMEDIATELY to check for the melted fuse panel when faced with an inoperative fan. Yes, the fan draws excess current and melts the fuse panel. That is cause of failure. It's likely that you did need new fans to be honest, but not being able to find the reason the new ones don't work is totally embarrassing.

You should refuse to pay that huge diagnostic fee. They wouldn't have racked up all of that time if they checked the basics first. STEP NUMBER ONE IS CHECK FUSES. The INSTANT that the fans failed to respond to the computer's output test, I would have checked that fuse panel.

This should have been a very quick diagnosis. There's no reason for you to pay for three hours of diagnosis because they couldn't be bothered to check the obvious basics.

Those fans are available aftermarket, I believe, for much less than the OEM part. Take your car to an independent shop and get this job done in a quick and cost effective way. You do need those fans, after all. Check for a good VW or European repair shop in your area. Tell them your VW did that thing where it melts the fuses and they'll know what you're talking about before you finish the sentence.
posted by Jon-o at 8:39 PM on August 6, 2010

Response by poster: Thank you everyone, I am humbled. For any more work that is required, I plan on taking my car to a very cute mom and pop type VW place that was recommended on a VW enthusiasts' site.

I think my next AskMe question will be how to stand up for myself when it comes to customer service. It's ridiculous that I have a hard time complaining about a restaurant meal or being overcharged at a VW dealership - you see, I spend my working days in an emergency department assessing people with acute mental health problems, and I can be in a very small room with an agitated, violent patient and not blink an eye - but I can't raise my voice at the VW dealership...
posted by analog at 5:52 AM on August 7, 2010

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