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Hello! New to BMW CCA.. need some advice on e28

Discussion in 'North Atlantic Region' started by theyellow75, Oct 24, 2014.

    • Member

    theyellow75

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    New to this club as of last year. I've owned about 4 various e9s since the 80s but recently found a wonderful e28 (86 535i) on for sale on the side of the $600!

    No rust, runs strong, but.. the battery dies overnight. I replaced the alternator, license lamps, and finally traced the problem to the main relay. I took out all the relays and the battery stayed at 12 amps and after putting in and taking out one after the other I found it to be that the "main relay" was warm and drawing power..

    So now what? I tried researching this online and became very confused. Some said to start pulling wires off the ECU which I have no knowledge or interest in doing.

    If I can get this fixed I'll hope to go to the race on the tenth.. not to win but have fun and meet you all.

    Thanks much.

    Matt
    • Member

    MGarrison

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    I would just replace the relay, I don't think they're particularly expensive, & it's probably not a bad idea to replace 30 yr. old relays anyway.

    I'm not sure that every single possible question has been asked there, but search first before asking over at:

    http://www.mye28.com/
    • Member

    theyellow75

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    Thanks. I did replace the main relay. I replaced all of them. When I plug the main relay in, after a few seconds it becomes warm.

    I've also searched the web quite a bit and have found nothing specific.. in fact this post comes up on google in the first page.

    I'll try mye28 again.

    Also I made an error in my OP , e10's not e9s.. I wish!
    • Member

    MGarrison

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    Here's etms, maybe one here can be of help -

    http://wedophones.com/BMWManualsLead.htm

    One thing on older BMW's, with a wiring diagram you should be able to identify all inputs and connections to the relay, at which point you get to testing and eliminating each - I don't know how likely it is, but given the age by now, it seems a possibility that wiring insulation could fail making for a short on a run of wire within a wiring harness - no fun to try to track something like that down. But, you have to start with the most likely -

    Wiring diagrams here:

    http://www.armchair.mb.ca/~dave/BMW/
    charlson89 likes this.
    • Member
    • Technical Service Advisor

    charlson89

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    That is some very good information to help find what powers the relay that could be causing the issue besides the DME.

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