E39 elecrical problems

[gmccormack 0]

I have a small problem. A 1996 528 had been sitting unused for 6 months. Try to start......battery dead. Removed and recharged the battery. As soon as the battery cables are refitted every exterior light comes on, brake, tail, head, indicators on solid, reverse lights everything also the wipers and washers run too all while switched off. Every other electrical circuit is dead, no dash lights no crank or start.......nothing. Any thoughts.

[Allanw 1071]

The battery is probably poked if it's been sitting that long as was flat.

I'd start there first.

Even just try one from another (going) car. Make sure it's big enough.

[yng_750 247]

I have to agree. I have heard of alot of random issue with dead battery. like car starts but trans goes into limp mode. try new battery first. Easiest thing to do

[B.M.W Ltd 950]

You sure you didn't fit the battery round the wrong way or reverse polarity recharge the battery ??

[gmccormack 0]

Turns out he had reverse changed the battery. New battery in the car now and things have improved......slightly. As soon as the battery was connected the front passenger side park light comes on as does the front and rear fogs on the drivers side (lights are switched off btw) rear windows went half way down on there own then stopped, now no window or light controls work. Engine cranks but will not fire, what damage has he done?? is it a write off ?!!!

[hotwire 352]

It has probably done substantial damage to many components - ECU's/ modules. You will need to get it professionally checked.

In effect it has been fitted reverse polarity & since t=yo have had the ign on - everything has been powered up wrong polarity.

LCM sounds toast for a start.

As comparison, just last week I had a mid 90's Mitsi Diamante at work where the owner had fitted the battery back to front.

Normally in this situation, it will blow the main fuse/s & usually not other damage. In this case, he had obviously turned the ign on & tried to start. (not that he acknowledged) - $1700 later the car lived again.

Good luck!

Edit: Seriously I mean, not sarcastically.

Edited June 26, 2014 by hotwire

[yng_750 247]

You can check the main fusable links yourself. After that either call an auto sparky or buy a 10l jerry of 98 unleaded.

[sonic_attack 89]

$1700 is another whole Diamante. lol!

[hotwire 352]

$1700 is another whole Diamante. lol!

Yes but it was a job that progressed to that. The obvious had to be repaired to confirm other problems. Owner was caught between a rock & a hard place.

[B.M.W Ltd 950]

Turns out he had reverse changed the battery. New battery in the car now and things have improved......slightly. As soon as the battery was connected the front passenger side park light comes on as does the front and rear fogs on the drivers side (lights are switched off btw) rear windows went half way down on there own then stopped, now no window or light controls work. Engine cranks but will not fire, what damage has he done?? is it a write off ?!!!

I would get it checked first by a competent Electrician or talk to Brent and start buying modules or sell it to him. I have seen this happen many times and it can be very, very expensive.

An unnamed customer once hooked up his running AMG Merc to his wifes new 6 series BMW with the ignition on, the wrong way round.... over $10,000 gone in 1 second and two tow trucks needed

[Allanw 1071]

An unnamed customer once hooked up his running AMG Merc to his wifes new 6 series BMW with the ignition on, the wrong way round.... over $10,000 gone in 1 second and two tow trucks needed

D'Oh!

If you don't know how to do it, DON'T!

[polley 916]

I have various e39 modules LCM etc you can use to test /buy.