Fuse number 21.

[jacko]

Can anybody tell me what fuse 21 is for, i have figured out that something on this line is draining my battery and i dont have any books to refer to.
Much obliged.

[Dan318-is]

Interior, glovebox and luggage compartment lights, torch, clock, radio memory, on-board computer

theres an article in the articles section dude, on the top ^^

[jacko]

ok now thats sorted how on earth am i gonna find the offending article. i have disconnected the earth from the battery and connected a meter between the battery live and the earth clamp, it reads 1.5 v and gradually falls to o.o3v after a few minutes. Any ideas where i should begin cos a sparky i aint!

[Dan318-is]

a bad earth parhaps

to be honest i only know basic automotive electronics

you need a hero such as brainmoore or smithy 318i to help

does the fuse keep blowing if so i would imagine a bad earth on one of the things which the fuse operates

just a guess tho dude

[dazleeds]

look here

http://www.e30zone.co.uk/modules.php?na ... 0fuses.htm

[jacko]

no, the fuse dosn't blow but i just can't figure why any of the components on the circuit would show voltage for just a few minutes with the earth lead off. As soon as you strike the earth again it shows the dropping voltage all over again. cheers for your help anyway my friend.

[Dan318-is]

no probs dude

try PMing or getting in touch with smithy318i or brianmooore

[jacko]

well the plot thickens! The problem lies with the interior light, but strangely enough the light is working fine. The thing is though, the power starts to drain when the doors are closed but as soon as you open a door the meter goes straight to zero, but as i said the light seems to be working ok. Any ideas really welcome now guys, cheers.

[Brianmoooore]

ok now thats sorted how on earth am i gonna find the offending article. i have disconnected the earth from the battery and connected a meter between the battery live and the earth clamp, it reads 1.5 v and gradually falls to o.o3v after a few minutes. Any ideas where i should begin cos a sparky i aint!

If I read this correctly, you are doing something fundamentally wrong here.
The meter needs to be set to measure current (amps), not volts, and should be connected between the battery negative terminal (red wire of meter), and the earth wire that you have just removed from the battery (black wire of meter).
Best way to do this is to loosen the battery earth clamp, clip the black meter lead to the earth terminal on the front strut tower, push the red probe of the meter directly into the top of the negative battery pole, and then lift off the negative clamp up over the meter probe.
This avoids any current surges due to things like alarms arming themselves, and also the need to reset and recode things like radios and OBCs.
Start with the meter on a high current setting, and turn it down untill you get meaningfull readings
Anything up to about 70mA is normal, depending on what equipment is fitted.
Fuse 21 is only glovebox on cars up to about 1988. Later cars, glovebox is on 4.

[Guest]

Don't get me started on fuse 21!! I have had to remove this monkey completely for at least a year now.
Car is 1989 325i cab by the way.

I got in one day started up fine all normal, got to my destination turned the key to turn car off. Imagine the surprise when i removed the key and all dash likes were still lit up and engine was still running!!

I have talked about this before on here but not much progressed was made.
Anyway went though all fuses until reached fuse 21, removed it and car was back to normal. albeit without clock, radio memory (v.annoying), interior lights.

Any ideas???

[Brianmoooore]

Don't get me started on fuse 21!! I have had to remove this monkey completely for at least a year now.
Car is 1989 325i cab by the way.

I got in one day started up fine all normal, got to my destination turned the key to turn car off. Imagine the surprise when i removed the key and all dash likes were still lit up and engine was still running!!

I have talked about this before on here but not much progressed was made.
Anyway went though all fuses until reached fuse 21, removed it and car was back to normal. albeit without clock, radio memory (v.annoying), interior lights.

Any ideas???

permanent live and ignition live come together in the radio. A short between the two here would cause the engine to ignore the key.

[Guest]

just had a look at schematics it looks like you mean s319 this is a splice point isn't it?

Next question, where is it??