I had my car parked about a month; after starting it I suddenly discovered I had no brake lights. I quickly tracked it down to a blown fuse #12 (8 amp). Replaced it, took it for a drive and all is well.
I’ve owned this car for about 12 years and it’s the first time this has ever happened.
I noticed in Bentley page 22-20, there’s a note that the high-mount brake light on ’86 and ’87 E28s might have a defective brake light switch. There was evidently a recall campaign #86V-151 to replace a defective brake light switch but I don’t know if it was ever replaced on my car.
Is this a common issue? I don’t mind replacing a fuse once every decade or so but I’m wondering if I should be looking for a problem somewhere. However it would be difficult to diagnose unless this problem pops up again.
On a related note, I noticed my ’85 635 has “blade” type fuses. Were the problematic “torpedo” fuses used on all E28s?
Blown Brake Light Fuse, No Apparent Reason….
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Blue Shadow
- Posts: 10281
- Joined: Feb 12, 2006 12:00 PM
- Location: SE PA
Re: Blown Brake Light Fuse, No Apparent Reason….
it happens
Fuses can get tired over time and use and then not handle an initial surge.
Fuses can get tired over time and use and then not handle an initial surge.
Last edited by Blue Shadow on Sep 28, 2024 2:30 PM, edited 1 time in total.
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MisterFixit
- Posts: 982
- Joined: Jul 21, 2006 5:01 PM
- Location: Golden, Colorado
Re: Blown Brake Light Fuse, No Apparent Reason….
Possible short circuit -
I saw this in a customer's car while installing a rear light upgrade some time ago... Left rear light is behind the jack / wheel chock / jack handle stowage on the left, in between the trunk and quarter panel (fender). Normally the fuzzy cardboard covering over the rear panel protects the lights and those exposed metal conductors that route power to the various lamps.
His jack handle was loosely resting on its perch, without being secured. It slid back on acceleration, bumped against the tail light, and hit the power conductor... Direct short to ground when he braked, and POP went the fuse.
Don't know if this might be similar to what is happening to your rear light; simple to find out. And yes, I believe all E28 cars had torpedo fuses.
Good luck!
I saw this in a customer's car while installing a rear light upgrade some time ago... Left rear light is behind the jack / wheel chock / jack handle stowage on the left, in between the trunk and quarter panel (fender). Normally the fuzzy cardboard covering over the rear panel protects the lights and those exposed metal conductors that route power to the various lamps.
His jack handle was loosely resting on its perch, without being secured. It slid back on acceleration, bumped against the tail light, and hit the power conductor... Direct short to ground when he braked, and POP went the fuse.
Don't know if this might be similar to what is happening to your rear light; simple to find out. And yes, I believe all E28 cars had torpedo fuses.
Good luck!
Re: Blown Brake Light Fuse, No Apparent Reason….
Yesssss, Mye28 is up and running again.
Agreeing with the above posts I'd just wait and see what happens. But keep in mind the brake light isn't the only thing on that fuse, the stereo most notably, possibly with other things too, so even if it is blowing for a reason, it might not be the brake light circuit.
Yes, all E28s came with the crappy GBC fuses. A couple of the guys here have come up with a ATO fuse board retrofit, but it's mostly directed at the high load fuses of the fan and A/C which tend to melt the board, IMO. It's a good product, but if your only problem is the brake light fuse I wouldn't even think about it.
IIRC the brake light switch was an over current issue, probably due to the extra load of the 3rd brake light, but I don't think it involved the fuse blowing.
Agreeing with the above posts I'd just wait and see what happens. But keep in mind the brake light isn't the only thing on that fuse, the stereo most notably, possibly with other things too, so even if it is blowing for a reason, it might not be the brake light circuit.
Yes, all E28s came with the crappy GBC fuses. A couple of the guys here have come up with a ATO fuse board retrofit, but it's mostly directed at the high load fuses of the fan and A/C which tend to melt the board, IMO. It's a good product, but if your only problem is the brake light fuse I wouldn't even think about it.
IIRC the brake light switch was an over current issue, probably due to the extra load of the 3rd brake light, but I don't think it involved the fuse blowing.