OBC was dead. Used car dealer said that it

[Badshift]

is no big deal and that it only requires a new battery to bring it back to function. The car was a 1995 540i and I was interested in buying it but was not sure about his explaination for the OBC.

Do you know if really the OBC only requires a battery?

Thanks in advance again.

[shogun]

Even my old E32 from 1988 does not need a separate battery for the OBC.
In case of my car there is a fuse on the DWA (theft alarm device) and from the DWA comes the power to the OBC, as thru the OBC you can activate the DWA.
Check the fuse.
Or the bulbs are blown. Check that one too.

[mholbrook]

You can usually find a good OBC on Ebay for around $40 or so. They are real expensive new. I would not nix the deal for this one thing. I would however highly recommend a leak-down test before I bought a BMW V8 with a Nik engine (1994-1995).

Mike

[sbcncsu]

is no big deal and that it only requires a new battery to bring it back to function. The car was a 1995 540i and I was interested in buying it but was not sure about his explaination for the OBC.

Do you know if really the OBC only requires a battery?

Thanks in advance again.

It is probably the light bulb behind the display. It may appear that the OBC is dead when in fact, it is just the bulb. To test this, press the turn signal stalk with the engine running and see if the display comes up in the check control area of the instrument cluster.

HTH.

[AllanS]

If you want to be devious....

Get a written quote from a legit BMW dealership, for the total cost to replace the entire OBC, including labor. This'll probably be a good chunk of change. If it's not, ask them to include the price of a new Motronics box plus labor.

Now, bargain the used dealer down to the lowest you can; then, show him the labor quote and have him subtract the quoted price.

Then, do the repair on your own.

[nykid]

If the display doesn't come up in check control area what could the problem be? I have tried 3 units form Baviarian auto parts, and they are not working. ZDoesn't seem right. Help

[Paul in NZ]

I dont undestand.Are you saying the problem is the obc or the cluster?

[Ross]

Shine a light at the display to see if it's functioning, if so it is a simple matter of replacing two bulbs.
No battery for the OBC. E30s had a battery in the cluster for the service indicator. This is maybe where the confusion stems from. Even that one is not a simple pop in a battery job but requires disassembly of the cluster and soldering. Probably a couple hundred bucks worth if you are paying someone.
There is a reason this guy is selling cars and not fixing them.

[Tiger]

4 years old post!

[Ross]

Do you think he bought the car?