Had to get my car towed because a rock chipped the radiator;

Used the head unit while waiting for the truck, that was fine. After we arrived at the shop, the truck driver let the car down and tried to crank it for about 2 minutes (battery had evidently run flat). Eventually, it wouldn't start so he jumped it and drove it into the shop.

The shop replaced the radiator and everything is fine but now the head unit doesn't start.

It's an aftermarket system with a screen and doesn't turn on at all or do anything noticeable - what steps should I take to fix this?

The car is an '06 tdi passat.


  • 1
    Details about the aftermarket system would be helpful.
    – CharlieRB
    Oct 18, 2016 at 16:53

1 Answer 1


When head units get disconnected from the battery, many of them "lock up" and need to have the security code entered again (they think the are getting stolen). If your battery ran flat or if the mechanic disconnected it (maybe he needed it out of the way for your radiator repair), this is what happened.

Also take the time to check the fuse for the head unit, there's usually one in the fuse box and one on the unit itself, usually at the back. Jumping a battery sometimes causes weird things.

  • How would one enter this security code?
    – Honwang
    Oct 18, 2016 at 20:23
  • What's the exact make and model of your headunit?
    – tlhIngan
    Oct 18, 2016 at 21:08

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