Electrical troubleshooting e34 91 525iA

[v4tuna]

Here is all that has happened so far and am out of ideas.

Driving home Friday hit the brake to stop and my radio went dead. Flickered on then off then DEAD. Check engine , Trans Prog, ABS lights all came on.

Drove home stopped car. It would not restart...groan groan like a dead battery.

Waited an hour tried again got the car running ran for a while Thn all wrning lihts came back on....while car was idling I tried turning on Headlights and it almost killed the engine.

Am I simply looking at a Dead battery or something more

I checked the one fuse beside the battery and it looked ok ...was going to try a jumper across to see if the Fuse is faulty but though I'd ask here first.

[glen-sj]

Have you check the voltage on the battery? Should read 12.5v or higher without the engine running. With the engine running at idle it should read around 13.75v, anything less means your alternator is not putting out enough current, then your alternator should be suspect.

The fuse beside the battery is the fusible link. You'll know by looking if it is blown (broken). Good Luck

[shogun]

I assume the fusible link has a haicrack, although it might look o.k.
Good idea to jumper the fuse for a test. Often one cannot see the haircracks so easy.
http://www.bmwe34.net/e34main/maintenance/electrical/fusible_link.htm

[v4tuna]

Thanks for replies

I did find that post on the fusible link and that is why I thought I would jumper. Replaced the Battery today ( costco is so nice) and of cours full charge batteryall looks ok. I don't have a digital meter to check so tomorrow am I will head over to my mechanic friend and get a proper reading...I still suspect something with alternator...that fusible link will be replaced as soon as I can get one...Just in case:)

[v4tuna]

Ok New Battery in

Volt meter reads 12.3v

Then I start up the car Votmeter at Battery drops to 11.7v

Will the Fusible link effect the charging ?

I

[Dave M]

Ok New Battery in

Volt meter reads 12.3v

Then I start up the car Votmeter at Battery drops to 11.7v

Will the Fusible link effect the charging ?

I

No, fusible link shouldn't affect charging. You can 'jump' the link like you intended to help confirm this? First think to check are the brushes on the alternator. If they look OK (Bentley has the minimum length), pull it out and get it tested.

Dave M

[Dave M]

Oh, get this sorted out before you need to boost this new battery ;)

[v4tuna]

Nt

[Dave M]

Nt

If you get a really good one, you can forgoe the alternator all together :p