Fuse # 21 keeps blowing, please help asap

[87-325ic]

well,
heres the full story,

My glovebox is off, and so i clipped and left dangling the flashlight charger wires, long story short, they got crammed together and smoked Very profusely,

this blew my Tach, Eceonometer (mpg guage), Stereo power, Map light, and trunk light, plus who know what else,...

i checked all the fuses and number 21 was blown, and this is where it gets good...
normally a 7.5 should go in there, but i made a big mistake and wrongly read that a 30 amp goes there,

i put that in and continued driving, and my problem still wasnt fixed..

i got home later that day and realized my mistake, i replaced it with a 7.5 amp and it blew as soon as it touched, the contacts... (it was nighttime and i could clearly see a blueish spark)
the 30 had been melted and disfigured, but not blown completely

so i replaced the flashlight charger socket, and tried again, it still blew!


>>>>> my thinking is that while the 30 was there, it was melting and or shorting somewhere else in some wires im unsure about..

does anyone have any ideas or suggestions as to where i should begin my search?


id be fine driving around with now map light or tach, but what really worries me is that something vaguely called "Fuel delivery" is also on that same fuse...


please help.

[MitchFong]

i have the same problem. Except i changed my #21 a month ago when it blew and it was fine till yesterday. I turned my headunit off while driving, and when i went to turn it on later that day it would not work. So i was really confused and then i saw my tach was not working along with fuel consumption so i immediately knew it was fuse # 21. Anyways, i went to put a new 7.5 amp fuse in and it blew as soon as i put the negatively wire back on the battery. Time to start tracing wires i guess. This happen to anyone else before?

[Slowpoke]

Old thread, but i have the same issue. Just bought for cheap knowing the tachometer and various gauges where not working. Started looking for a simple fix and this is where i am at. Anyone have any staring points?

[Ferdinand]

The trunk light is on Fuse #21.

Check the wire to the trunk light. It runs from the body up the left-side trunk hinge and then to the trunk light. Where the wire first touches the trunk hinge it can chafe and eventually cut through the wire insulation.

Fuse 21 kept blowing on my 86 325e until I finally discovered the insulation had been rubbed through on that wire. I wrapped some electrical tape around it and that cured the problem for me.

[Slowpoke]

Thanks for the info. I checked the trunk light and everything looked fine. I also read in another post to check the wires to the reverse lights around the shifter. I couldn't find them.

[Ferdinand]

Thanks for the info. I checked the trunk light and everything looked fine.

I'm sorry to hear that.

In my case, studying the wire diagrams for Fuse-21, I was depressed to see how many different circuits that involved. How would I ever find where it was shorting out? Finally I decided to check the simplest things first, starting with the trunk light, and Aha! I was soooo happy when I found that was the problem.

I also read in another post to check the wires to the reverse lights around the shifter. I couldn't find them.

You have to pop up the shift lever boot. Then the reverse wires run down through an opening in the rubber boot that's below that. The bad news though is that the reverse lights are on Fuse-10, nothing to do with your Fuse-21 problems.