Is a blown fuse a sign of future problems?
 

The fuse to the instrument cluster blew on the way to work today. All the gages just died. I replaced the fuse with no problems and everything works again.

My question is....is this a sign of future problems? does this warrant future investigation? why did the fuse blow to begin with?

This has been the coldest day of the winter so far (25 degrees F). Maybe that had something to do with it?

Your car is a 1973 220D right?

I'd say don't worry unless it happens again. Then it would be time to worry about a short or something else.

this is for the 90 350sdl

High-draw components I'd be concerned with... There could be a short someplace - did the cluster come back to life after swapping the fuse? Once I caused a short in a BMW cluster, but it burned through the traces...

Blown fuse = resistance, short (or old age). It would blow immediately if you had a direct short to ground. You could pull out the volt meter and set it to amps then look for any excessive draw. I'd probably change the fuse making sure that it was the proper size and see if it blows again. A worthwhile project is make sure that the contacts in the fuse box are clean where they make contact with the fuses. Deoxit works well for cleaning contacts. You could go wild and clean every contact you can get to - it couldn't hurt. Some on my SD are nasty but it is cold outside.

Could have just been a thermal problem with an old oxidized fuse contact. Make sure the contact points of the fuseholder are clean.

If there is a problem the new fuse will let you know. Yes the cold could have contributed. No sense going looking for a problem at this point as none may exist.

Actually, you might be on to something there because when I took out the blown fuse, it wasn't blown in the 'regular' middle narrow part. It was blown on one end. And when I took it out, there was a lot of oxidation (gray dust) where it blew.

I guess that was it. Thanks!

"Is a blown fuse a sign of future problems?"
No, it's a current problem. Sorry, just couldn't resist. Corroded fuses will do that. I'd just wait & see if it happens again. If you have any others like it a light mist of WD40 will prevent any more corrosion. Be sure to get it on the back side of the element also.

While you are at it, replace any aluminum (gray or silver-colored) fuses with copper.

I think we may have opened the proverbial can of worms now. Get ready for 2 pages of the pros & cons of WD40 and copper fuses.

are you saying this because copper is less susceptible to corrosion (compared to the other metal) hence there will be less blown fuses due to false alarms?

if we get enough worms we can have a fishing tournament

No nooo... ya need to drag your quad trace O scope out there and do it right. Please post pics of your traces.

Well I should probably avoid reading this forum because one of my fuses blew, but it was just an old old fuse that corroded. Replacing it fixed it :cool:

BTW, I'm located about 50 miles west of Gainesville, Fl. If you have any problems in the area you're welcome to use my shop. PM me for contact info if you want. Hope you have a safe "uneventful" trip.