Jetta Wagon Won't Start After Welding

Hey guys. New here. I had a Body shop weld a huge part (from another 2014 Jetta Wagon) from the driver fender to the back driver door due to an accident.

Now the ignition won’t even come on. Only basic things like headlights, radio, unlock/lock button, and the dashboard showing the mileage works.

After digging a little, the welder got really close to the Body Control Module. There’s even burn marks on it and one of the relays looks burnt. The relay isn’t bad though and when I unplug the BCM, the car has even less functionality.

I read that if a BCM is bad, it affects power mirrors, power windows, air conditioning, and the immobilizer system which all don’t work.

I’m guessing it is the BCM, but can it be something different like the Ignition control module or ECM? It also has the power steering issue light on the dash.

I would really appreciate some info on this. Thank you!

Did the welder disconnect the ground cable to the battery before he started? If not, you may have more than a fried BCM. Since the car won’t start, the ECU may be fried as well as the BCM and the burnt relays are a huge hint.

You have a big job ahead of you. I am not even sure where to tell you to start. The car might be a write-off. A bad BCM won’t usually prevent a car from starting so… bad things, very bad things.


Thanks for that information. He claims he did unplug the battery, but he also did lie about some other things, so who knows. I doubt he grounded it though.

True, the plastic on 1 of the relays is burnt, but there’s a deep burn mark the size of a quarter on the cover of the BCM which is really close to the relay that was burnt too. Th fuse tester showed that the relay was still good if that matters.

The car sometimes says “Keyless defective” and sometimes the radio works and sometimes not which makes it seem like it’s the BCM.

I guess I should start with replacing and reprogramming the BCM and go from there?

Ask the body shop if they connected one of these to the battery before welding on the vehicle.


Because you don’t indicate that they’re taking responsibility, if the body shop wrecked stuff on your car, it’s their responsibility to pay for the fix.



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I stand corrected, Thanks @Tester

So I ordered a new BCM and after connecting it, it seems like the car is behaving the same way like the old one.

Before I get this new one programmed and throw in even more money at this car, does anyone have an idea if that means that the old one is not bad?

Why are you doing anything? Take it back to the body shop, tell them “it ran when I brought it to you. You need to see to it that it runs again.”

The more you do to the car the less likely you’ll be able to get them to fix their mistake because they can just point at what you did and claim it’s your fault.


Explain in a little more detail what you mean by “it won’t start”. When you turn the key to “start”, what happens?

  • no sounds, engine doesn’t crank
  • a click sound, engine doesn’t crank
  • an “rrrr rrrrr sound”, engine cranks, but it doesn’t catch and run

Depending on which of those describes the problem, the next step then is to decide whether or not the spark plugs are sparking and/or fuel is being injected.

In order to weld something to a car, the body shop guy may have drained or depressurized the fuel rail system for safety purposes. If so, that may have been done by disabling the fuel pump and cranking the engine. Perhaps the fuel pump remains disconnected.

There is absolutely no sound when pressing the push start button. The dash barely comes on. It only shows the miles and that the door is open and a red power steering light. Battery is fine because I put in a new battery and it still doesn’t start.

He didn’t drain or depressurize the fuel rail system, but he did say 1 of the spark plugs was burnt and that he changed them all.

My wife signed something saying that they aren’t held responsible for anything when getting the car back, but I paid $0 for 30 hours of work because of his mistake.

If I thought the body control module was interfering with the basic functions of the vehicle, I would unplug it and see if operation is restored. It is a false belief that all vehicle functions not performed by the PCM are performed by the BCM.

The problem seems to be with the key and Access/Start Authorization Control Module. Begin with checking every fuse in each fuse box. Next step would be to check the data and function of the Access/Start control module with a dealer level scan tool.

Thank you for pointing me in the right direction, however the car doesn’t even get to the “ignition on” stage. A scanner gets power from the car but can’t recognize any car connected to it.

The welder could have made damaging voltage spikes anywhere in the electrical system,
with or without having the battery connected.
You need to find a mechanic who’s good with a multimeter.
All we can do out here in internet land is make wild guesses.


Okay I’ll just have a mechanic come and diagnose it. Thank you. I appreciate everyone’s help with this!

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