Fuse - BMW Forum

e30dream · 02-22-2007, 11:08 AM

So recently my #23 7.5a. fuse has been blowing out. Ive replaced it and it blows out again. I guess its just not that big of a deal but its kind of a pain not to have dash lights working at night. I dont know that much about electricity (didnt pay attention in 9th grade physics!) any suggestions? SHould i check anything?

the dash lights go out, the right side marker and right side tail light go out (when i turn lights on) and the computer seems to be out as well.

thanks for any suggestions!

german-speed-demon · 02-22-2007, 01:54 PM

Sounds to me like you might have a bad diode in your alternator, it could be backfeeding and blowing the fuse.

gotKRAUT · 02-22-2007, 04:19 PM

ya you def have a short somewhere, might wanna look into that sir

PhatCat · 02-22-2007, 06:07 PM

Check your transmografier where it connects to the hyper conduit.

e30dream · 02-23-2007, 01:27 AM

lol like i said, im not much of an electrical guy.
so i chould just get a voltmeter? and if i find a short *im assuming I have one due to the fuses blowing* what would be my next step?

sorry im alittle fuzzy on electricity...but hey.. thats why i come to all you guys!\

That is all.

shit wrong thread.

e30dream · 02-26-2007, 08:42 PM

so the short is most likely caused by the load drawing too much?

///M Power · 02-26-2007, 10:09 PM

It's probably your flux capacitor.

(i hate electronic issues)

gotKRAUT · 02-26-2007, 10:48 PM

werd, electronic issues go to the father in law, hes a 30+ year electrician lol

e30dream · 02-26-2007, 10:54 PM

alright ill swap it out of my DeLorean

Hamfisted · 02-28-2007, 01:18 AM

Does it blow only when you turn the parking lights on? Or is it blown before then? Knowing this will kind of shorten your search area. What year is your E30? I can send you the factory electrical diagrams to look at. There's a lot of little lights on that circuit. All the little interior lights, dash lights, side marker lights, ashtray light, etc... If the fuse blows before you even turn on the headlight switch I would suspect the headlight switch itself. If someone has installed an aftermarket radio I would inspect that wiring very closely for bare spots or improper splicing. Or even disconnect the aftermarket radio entirely to see it that circuit is the problem. Many times people that don't really know what they're doing install a radio and screw up the wiring.
If all else fails, they do make a circuit testing tool that plugs into that fuse spot and allows you to use a sensing probe to locate the short.

-Mike

e30dream · 03-01-2007, 11:40 PM

awesome. yeah when i replace the fuse it usually lasts a while, but then blows a while down the road. i do have an after market cd player in (its been in there for at least 9 months) and my newest installation is a sub tube (this has been in for about a month before my problem started. it doesnt seem to be linked to any sort of switch, but completely "random" to me. Thanks for your help!

oh btw, 1989 325i
front passenger side parking light
rear passenger side tail light (when lights are on)
license plate lights
dash guages (tach, speedo, fuel, engine temp)
clock/computer does not light up.

god i hate elctrical!

Rfitz25 · 03-02-2007, 02:34 PM

You can try a bigger fuse (Hack) if a part of the radio system is on that circut it will draw more current. When I first got my ride before I cleaned it all up the guy had higher rated fuses in some of the slots ie 10 amp fuses in 7.5 slots because they would blow periodically. Not anymore. Sounds like a short ie somewere a bare wire or connector is touching other metal ie round or another connector or wire.
Usually radio or alarm aftermarket stuff.

The manual lists all the systems that are on each fuse page 55 I think
SO that should limit your search. If you dont have the manual and want it I'll look it up at lunch.
ie I take 4 and 5 (I think) out for autocross, wipers and turn signals.

intermitten shorts are hard to find electrically, I usually have to find em visually. ie find the wire colrs and trace them, old cars get chaffing insulators connectors get cracked.

Otherwise I personnally think Backaroo Bonzai's oscillation overthuster from YoYodyne Inc works much better than the flux capacitor.

e30dream · 03-02-2007, 11:10 PM

yeah i got a manual... in the back of GFs car tho...have to get that...

thanks for the help guys. i appreciate it.

oh yeah riftz, has the BMW CCA meet in SD already pass?

Rfitz25 · 03-05-2007, 02:14 PM

Oh yeh BMWCCA SD Autox was Sat. 3rd Qualcomm stadium East lot.

WHAT A FRIGGIN BLAST !!!!!!!!!!!!!!!!

But wait its not too late, theres another one in East lot again on March 31st!!!

SD BMW CCA Calendar

West lot in May I think labor day weekend, 7th?.
You should come out and drive.

It was way better than SCCA SOLO II
You get 8 practice runs in 2 sessions then 3rd session is 3 timed run for the trophies.
At least 10 other E30's too.
and the numbers are nice stickers for the windows instead of sheets of paper you tape on the doors.
$45 instead of $20 though for members but you get a good lunch and I couldnt believe it but Starbucks coffee and muffins at registration. so nice at 0 dark thirty in the morning. :lol:
I got my ass kicked in modified 6 cyl class, LOL but had a blast, would have been in top few in stock class. 104 sec fast course too, very nice.