computrtutr

I have a 2000 1.8tqm.
Last year, I had a problem where my battery was not properly charging. In May, I bought an alternator and battery and things worked well for 9-10 months.
A couple of months ago, I was driving it, and the yellow autocheck light for the battery came on. I pulled off the next exit and made it to a parking lot before the thing died. I let it sit a while and was able to start it. I called a friend and he came by to accompany me home "just in case". The car died and we jumped it, but the insulation melted off the cable while both batteries were connected. We verified that the correct terminals were corrected (no switched polarity). We called AAA and got my car towed. I took a look at it and could not find any loose wires or obviously failed parts. I replaced the alternator and battery, both of which were still covered under warranty from the prior year.
I ran the car occasionally while I waited for the cash to take the car to the dealer for an assessment. This battery also tested bad (!)
So far, the dealer called and told me the problem was that the battery "must have been connected backwards at some point". I know this is not the case. The dealer told me that the whole car was probably fried because the engine grounds through the instrument cluster, and that I "probably have a bunch of modules to replace". Now, I have no errors or lights, and when I took the car to the dealer, I was able to drive it, and everything worked fine (ABS, radio, lights, fuel pump, instruments, HVAC, etc.). The only thing not obviously working was the charging system.
I think most who read this post will agree that these must be the words of a service manager who heard a couple of disjointed facts from a technician and really has no clue what he's talking about.

However, giving him the benefit of the doubt, or possible assuming that the melted jumper cables were a result of a battery failing and sending a spike or something through the car, here is the question:
What am I likely to need to replace?

I'll post with updates.
Thanks!

4Rings::G2 boosted::

that's about the only thing that will melt insulation from the cables. Check your starter and starter solenoid first, those are about the only items that do not have breakers on them due to amount of power needed.

The battery test is bogus, any battery that's low on charge will test bad. I wish the dealers wouldn't do that, I wonder how many folks per year get a new battery unnecessarily. I know when my wife's Beetle starter was going bad they also tried to talk her into a new battery. It took 1/2 hour of convincing to get them to replace the starter. Afterwards the battery was and still is just fine.

computrtutr

I replaced the battery, and the alternator, and he says that the instrument cluster is probably bad... So I told him to pack it up and I'll handle it from here...
Any idea where to get an instrument cluster? He told me that job is $1500 in parts and $500 in labor. I have R&R'd an IC before, so I'd rather get one elsewheree and spend my 20 minutes replacing it.

4Rings::G2 boosted::

I seriously doubt there's anything wrong with your cluster. The engine doesn't ground through the cluster either, that's total bs.

computrtutr

and the mechanic says that the problem I am having is that the alternator gets its agitation from the cluster (I guess that's what the service manager was told and he misunderstood). To troubleshoot the charging problem my car is having, they have replaced $900 in parts (fortunately all under warranty) and they want me to authorize another $2000 for the IC. I am pursuing other options!

David.Norton

sounds like he is just replacing parts. There is not much in a car that can burn jumper cables, 4rings is right, it is going to be the starter, alternator, or the wiring between. Unhooking a few connectors and a few minutes with an Ohm meter should sort it out. I would also note that if you drove it in and it now has a bunch of other modules failed you have to wonder what happened.

computrtutr

I am wondering if all those things really are "failed". If I see a bunch of new lights on the cluster when I go to pick it up, then I'll know that the mechanic doesn't know how to use his own tools, and then I'll have a case. In the meantime, they have told me that the car needs $4000+ in repairs. I knew the clutch was going, but I wasn't about to buy a $2000 instrument cluster!
So far I'm kinf of annoyed because they are charging me $220 plus tax, and they say they have to put in another $2000 part to get any further. Can't a multimeter determin if the correct agitation signal is coming from the instrument cluster? I'm gonna break out the Bentley on this!

computrtutr

Can I use the VAG-COM to follow the diagnostic steps in the Bentley manual (starting in section 01-79), or is it too different from the scan tool used by dealerships? I want to check the DTC memory and see if there's a way to check the IC signal to the alternator. Alternatively, where could I find a test that verifies this? I would guess that removing the agitator connection from the alternator would be a good start. Is that something that can be tested by grounding it to see if an indicator appears on the IC, or would I short something out?

Also, which VAG-COM interface do I need?

Thanks!