BMW E30 320i - no electrical power at all - can't turn it on

[spp320i]

Hi all, new guy here, in need of some help!!

I have a H plate M20 320i, the other day I had a strange problem, and after lots of internet searching, have not found any help.

I went out to start the car, did so fine. Next thing I did was plug in the phone charger into the lighter socket, and the car spluttered and died. I tried to re start the car, and nothing, no cranking, nothing. All the electrics are gone, no lights, windows, hazards, central locking or anything. Been the same since. I did find a small piece of metal in the socket, so could have shorted something.

I've checked the fuses and all seem fine, can't see a blown one anywhere. I've taken off and re-connected both battery leads and the terminals look fine too. I'm going to go and swap some relays with a couple of spares I have (always worth taking from the scrappy). All leads look fine.

Can anyone help? I don't like electrics that much, but can do the basics. Am I missing something? Are there some more fuses that are hidden away? Could be a bad earth, so I'm going to check the grounding points that I can find as well. Any obvious connections to check?? I don't see how the battery could have died if it started just before, unless I fried it!

Thanks in advance!!

si

[protomor]

Ive seen batteries explode under similar circumstances but i dont see why it would in your case. Try another battery. Otherwise, the most likely problem is a fuse. You can look up a diagram that tells you which fuses go to where, you might want to locate which one is in charge of the lighter socket.

on second though, it shouldnt be a fuse. Other parts of your electronics shoudl work... *shrugs* try another battery.

[spp320i]

Thanks, appreciate the help. Not sure it'll work, but I'll try anything!

Any more suggestions anyone.....??????

[Brianmoooore]

There is no way a short in the lighter can kill all the electrics on a standard E30. All that should happen is fuse 28 should blow.
Unfortunately, in the 16 years since the car was made, it may have recieved the attention of audio/alarm cowboys,or fitters as they prefer to be known, so anything is possible.
First check: Check the car is not in gear, remove the cap of the engine diagnostic socket, and carefully identify pins 11 and 14.
Short them together with a short piece of wire. This should make the starter motor work without the ignition being on.
Post again with the results.

[spp320i]

Thanks Brian, I will go and have a go in a minute. I think I've got a picture somewhere so I can see which pins are 11 and 14, but in case I can't find it, do you guys know where I may find this info?

I'll let you know if i have any success and keep you updated.

Thanks again, watch this space!

[Brianmoooore]

Pins are numbered in the socket, but it's not always obvious which number refers to which pin.

[spp320i]

Brian,

Have done the above, worked fine. Battery definitely has power.

I did find something though when I was checking all the fuses and relays etc.

With the ignition switch on, you can normally hear the ICV clicking away, and I found that relay K8 has an effect. When I pushed K8 down, click click click went the ICV, power was back. Then, I switched K4 and K8 to check the relays were behaving in the same way. They were.

I managed to start it a couple of times, but then using any electrical power caused it to cut out. I also found that the "clicking" stopped whenever the ignition was on and I tried to use any electrical parts - windows, lights, hazards, wipers, anything. It seems like this relay controls the power to the ICV and everything else, but Haynes says its just the fog lights!! When I try to use any electricals, it kills the power, you can hear K8 clicking off. Then with a push and a wiggle again it's got power.

It can't be the relay, I checked it against K4 and another spare I have. All did the same. It can't be the connection to the relay, or trying to use the windows wouldn't cut it out if it was just a dodgy connection. I can feel the click of the relay switching off when you try to use the electricals.

All I can guess at is that there must be a short somewhere - would this be it? How can using the accessories turn off the relay otherwise?

So what do I do next? It's good at least to know that it's not fried!! Greatly appreciate your help on this, it's a slightly strange one for me!

Thanks a lot... Looking forward (!) to the next chapter!

[Brianmoooore]

There are three wires to the battery + terminal: The big black one to the starter motor, which is OK because the engine turns over. A red one to the engine loom, which is OK because the starter solenoid operates from the diagnostic socket, and another red one to the fusebox, which supplies power to the car loom and ignition.
It seems there is a problem with this last one - possibly inside the fusebox, but not a problem I've seen before.
Think the next step is to open up the fusebox. Unscrew the obvious screw outside of the cover, the one inside the cover, and a third one hidden under a relay. The top half of the fusebox will now lift off, although there are loads of wires making it difficult to do so.
You can pull quite hard - nothing normally gets damaged or comes adrift, except for a white plastic 6 (?) pin plug pushed onto the PCB. There's a 3 (?) pin black plug in there as well, which I've never seen connected to anything.

The red wire from the battery is anchored onto a cap bolt which can be seen from the top of the fusebox before dismantling. Maybe someone has loosened this at some time

[spp320i]

Thanks Brian, I'll go and attack it again in a minute, see what I can find.

Very grateful, update coming soon (I hope!)

[spp320i]

FIXED but not solved!!

While messing around in the fusebox, I checked all the connections and tightened the nut holding on the red wire inside, wiggled the rest a bit, and it seems to be ok!! Didn't spot the white or black plugs you mentioned, but there was a 5 pin white connector, but that had nowhere to connect to the PCB!

Will keep all updated if there are any further developments, but it appears to be ok, perhaps temporarily!

Thanks for all your help Brian, I owe you a pint sometime!