Hello and Welcome to justanswer...
It would appear from your description of whats gone on, that damage has been to to electrical components on the car..
Now this could b e the main ecu - the cars computer and / or the "comfort module " which controls all the items you mentioned as going haywire... or -and this is very possible too - burnt and / or short circuited wiring in the looms in the car...
You are going to need to check, very thoroughly and and as far as you can - the wiring throughout the car...including the earth wiring and contact points as a staring point..
After that -- there is not a lot you can do as it will come down to component testing - and this needs to be done with diagnostic equipment designed for the Beetle model... and as used by the dealers..
On this occasion, I would recommend using the dealer level equipment as the only sensible option here... as the damage that seems to have occurred will be very VW component specific..
But check your wiring through for anything obvious first.... and after that...its as above Im afraid.... The electronic components are very sensitive to anything like this happening I'm afraid...
I Sincerely hope I have helped you - Please ask me if you need more help...
Kind Rgds,.... MIKE
PS...Please press the ACCEPT button if you are happy with my answer/advice given- as thats how I get paid ;)
Feedback is always appreciated too... Thank you .
Hi there... Thank you for getting back to me...
This is likely happening because your battery is very flat - and you are applying "normal" power to the circuits and firing everything up.... but as you obviously know - all these things shouldn't be going off like that whatever...
Its not likely to be the ecu this fault - but it could well be the comfort module.... or the wiring... WHen the battery was connected wrongly, its very likely that live wiring was shorted to earth wiring --and this could well be why you are getting what you have...
This really must be checked out as soon as possible - -as , not to put too finer point on it... it could cause an electrical fire - certainly the odds are raised substantially if the wiring is burnt anywhere...
You should leave the vehicle without the battery connected until it is inspected.... That will stop the risk as above....
I personally had experience of this a couple of months back - a garage had done exactly as happened with your car....and instantly - the wiring was toast under the dash.... What Im trying to say is - you must be very careful here.... fire is a very real possibility - so have it inspected properly as soon as possible..
VW Mechanic
30 Years of working on vehicle repair/diagostics! ;)