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vicac1 · Posted: Fri Nov 02, 2001 5:27 am Post subject: boosting, blown fuses,

I just purchased a 89 535i I left the trunk lid openfo a day andmy friend came over to use my garage when he went to move the car battery was dead. he removed the seat and boosted it. He 'aperantly' had a problem boosting it later. when I camehome the battery was disconected,with a slow charge charger on it. I started the car ok
but now find that many of the electrical devices do not work. ie. power seats ,door locks, radio, clock, mirrors. I beleive that there must be a fusable link or big fuse or relay that goes from the battery to the fuses etc. on the left rear under seat location. I do not ---yet-- have the service manual, or an owners manual . so immediate help would be apreciated. also is there a spot to boost other than on the battery? I also noticed that the drivers doorwould not unlock with the key when the battery is dead. what if--.you locked the car and had the battery die?/ vic __

edjack · Joined: 04 Feb 2002 Posts: 3887 Location: San Jose, CA

There IS a fusible link on this model; I believe it's under the hood, somewhere on the right side inner fender. A friend's E34 had the same problem. Apparently, these things get old, and can open up by themselves. It's a cheap part, but the shop labor to replace it is not. If you can find it, and you are mechanically inclined, you will be able to replace it.

Unlocking the car with a dead battery is described in your owner's manual. It involves using the passenger door keyhole while pulling up on the outside door handle.

BTW, the lock system is electrical: there is no mechanical link between the keyhole and the door lock mechanism.

BMW jump start instructions caution against jumping with any vehicle whose voltage is above 15 V. Here's a condensed version:

1. Connect the positive jumper cable to the dead car, then to the live car. Use the B+ junction on the engine, if possible.

2. Connect the negative cable to a shock absorber bolt, then to the live vehicle.

My recommendation at this point would be to not run the live vehicle engine, in order to not have a high battery voltage.

3. Start the dead car. Before disconnecting the jumper cables, switch on:

heater fan to highest speed
rear window defroster
low beam headlights.

These accessories will tend to absorb any transient voltage spikes due to disconnecting the jumper cables.

4. Disconnect negative, then positive cables.