E34 dead battery , lock out

[stevieduk]

Hi I am sure this has been raised on here many times , but how do I get into my car when the battery is flat.
I have tried the overide position on both doors with the key , nothing. Next I got in the boot and tried to put power through the boot light after checking the polarity , but the wires started smokeing.
So it seems like iI am left with 3 remaining alternatives,
1 Get under the car in all this snow and connect power to the starter motor terminal.
2 Try and reach the bonnet latch cable from underneath to open the bonnet and get at the battery .
3 Put a hammer through a side window out of frustration to open a door.

Or does anyone have a better idea. PLEASE

[whiskychaser]

The boot light trick should work. I am guessing from your sig (and the fact you said 'boot') that you are in the UK. If so, you might be forgiven for thinking brown is live as thats the colour for live in a house. But a brown wire on your car is a ground. So if you are supplying 12 live straight to ground something is going to smoke. Unless you used a DMM, observed correct polarity and I am just guessing :-)

[stevieduk]

The boot light trick should work. I am guessing from your sig (and the fact you said 'boot') that you are in the UK. If so, you might be forgiven for thinking brown is live as thats the colour for live in a house. But a brown wire on your car is a ground. So if you are supplying 12 live straight to ground something is going to smoke. Unless you used a DMM, observed correct polarity and I am just guessing :-)

i did check with a meter before i put current through the wire. there is a brown and black wire and a brown wire. The brown and black got a continuity reading , so i presumed that was ground ? ? ?
Thanks for the reply anyway. I am surprised a company like B M W used such a stupid system.
What I need is a beefy cable from the battery to a socket under the car at the back like a tow hitch power socket, then if it goes flat again just plug in there and theres power straight to the battery.
PROBLEM SOLVED

[whiskychaser]

Best way to find which is ground is stick to one DMM probe on a known ground and the others on the wires you are testing. Cant see what car you have but wiring diagrams are here:
Free Phone System Manuals Voice Communications 800 593-6000

[stevieduk]

the car is a e34 518 1991 , which isnt on that listing you sent but thanks for trying anyway. I will try the boot " trunk " light again and if no joy this time , I will get underneath and go onto the starter motor,.
As british cars only have one bonnet catch , were you have two, i may be able to pull on the cable from underneath also

[whiskychaser]

Not about to broadcast how somebody can break into your car but check your in box

[stevieduk]

Not about to broadcast how somebody can break into your car but check your in box

what box . I dont understand

[shogun]

see on top of this page, scroll up where you find on the right 'notifications' blinking and there is a private message for you.

[632 Regal]

If the battery is dead (flat) you are going to have issues trying to juice it up. Too many required amps going through thin wire. Not sure why the key doesn't work though.

[shogun]

yes, Regal, I remember that with an E31 850.
Both batteries dead/flat, no juice at all, did not even unlock the doors. So I used my E32 750 with really thick heavy duty jumper cables, had the 750 running and tried to jump start the 850 via the 2 batteries inside the engine room. The jumper wires got really hot but nothing happened.