Weird electrical problem....

B6/7 S4/RS4
#1

So the past few days my car has been acting extremely weird. In fact, today I had to get it towed…figures since its Friday the 13th…

When I start it up the past few days everything electronic would die except the engine, then a few seconds later the lights and everything else would come back on. I figured it was just a battery on its way out. Then yesterday as I’m leaving my neighborhood, I shift from 1st to 2nd, get it into 2nd and the engine stalled and it felt like the drivetrain and wheels locked up and I went into a full skidding stop…really weird so I made an appointment with a mechanic for this weekend.

Today nothing came on. The doors unlocked at first, but then the trunk wouldn’t open, lights, dashboard, stereo, engine…nothing would turn on. Tried to jump start and same thing, nothing. Worst part is I can’t even run for codes because I have no power in the car even with a new battery in, which we tried replacing to see if the problem persists. The steering wheel is locked so that was a bitch to get it on the tow truck…

Any thoughts? Its a 2006 s4 with 88K miles. This is the first problem I’ve ever really had with the car. My guess is the anti-theft system maybe? ECU? I’m clueless as to what this could be. Seems like some sort of serious electrical issue

#2

So the car is totally dead?

Before you rule out the battery…

  • did you verify that the connections to the battery were completely clean and solid?
  • did you test the CCA on the old battery?
  • on the new battery, did you verify the CCA (that it wasn’t defective)?
#3

Have you done anything electrical wise to your car lately?

#4

No I have not. Last time anything was done was a sound system installment 2 years ago and a battery replacement about 8 months ago

Connections were fine and CCA was good. We even put an inverter on the old battery that is used to charge tractor trailer batteries (I think that’s what it’s called) and same issue occurred.

#5

Figured I would update in case anyone has the same problem in the future but turns out a harness to my ECU and a harness from the battery both were melted…makes sense

#6

Ouch! Any identification of root cause?

#7

Heat?

#8

Not a clue. I do a lot of long distance highway driving, usually at high speeds for hours at a time so that might be a reason…though still not a very good reason for wires to be melting

#9

Bizarre. I hope it was a one-time event, but without knowing the root cause… who can say it won’t happen again?

#10

Wouldn’t the root cause be that the insulation is in contact with a hot surface and that heat caused the insulation to melt? Do you have any pictures of the melted insulation?

If not, then the conductor is pulling too much amperage? I really hope not… but I would definitely want to find that out ASAP if it were me.

#11

It has something to do with the windshield wiper relay harness, they said, that comes from the battery to a circuit board or fuse box. This is either just the tip of the iceberg or the end of the road because we need to replace the entire harness in order to even talk to the car via VAGCOM so there might be more underlying problems to address. I haven’t been able to get to the car shop because I’m busy with med school stuff and really don’t have time to deal with this crap as the car going down right now is at a really bad time. They said they would hold on to the part for me to see after so I’ll post pics once I get a hold of it.

It’s just really weird that it would melt so randomly…and a really weird harness to melt to affect the entire car…

also I asked about wire contact and they said when they got to the wire it was not in contact with any heat-producing parts…even more bizarre…

#12

Not a clue. I do a lot of long distance highway driving, usually at high speeds for hours at a time so that might be a reason…though still not a very good reason for wires to be melting

#13

Bizarre. I hope it was a one-time event, but without knowing the root cause… who can say it won’t happen again?

#14

Wouldn’t the root cause be that the insulation is in contact with a hot surface and that heat caused the insulation to melt? Do you have any pictures of the melted insulation?

If not, then the conductor is pulling too much amperage? I really hope not… but I would definitely want to find that out ASAP if it were me.

#15

It has something to do with the windshield wiper relay harness, they said, that comes from the battery to a circuit board or fuse box. This is either just the tip of the iceberg or the end of the road because we need to replace the entire harness in order to even talk to the car via VAGCOM so there might be more underlying problems to address. I haven’t been able to get to the car shop because I’m busy with med school stuff and really don’t have time to deal with this crap as the car going down right now is at a really bad time. They said they would hold on to the part for me to see after so I’ll post pics once I get a hold of it.

It’s just really weird that it would melt so randomly…and a really weird harness to melt to affect the entire car…

also I asked about wire contact and they said when they got to the wire it was not in contact with any heat-producing parts…even more bizarre…