View Full Version : Yellow metal fuses?

06-12-2012, 08:29 AM
Had my car in for some service recently and mentioned that both the radio and first gear start engagement (B on the shifter, not aftermarket) were acting up. The tech looked in the fuse box, wiggled all of the fuses, and both items seemed to be cured. He mentioned to me that the fuses in these cars should use yellow metal, not white metal, as most of mine did. I suppose there is a problem with dissimilar metals and corrosion. So I installed all yellow metal fuses (copper, I guess). Since I did this my first gear is fine, the radio is fine, BUT I have blown the fuse for the front windows twice (never happened before), and now my turn signals have stopped flashing (possibly unrelated). Is the white vs yellow metal thing well known, and do the yellow ones tend to blow faster? Are there other related issues that anyone can share?

06-12-2012, 08:57 AM
Copper vs silver-colored shouldn't matter much, although some people have a preference one way or the other. I prefer ceramic body fuses over plastic but that's a different discussion. For the window fuses blowing, double-check to make sure you are using the correct rated size (8A, 16A, or 25A). Do this for ALL of the fuses. You'd surprised how many times I've found that a previous owner/mechanic installed the wrong size fuse in one or more locations! And yes, a bad fuse could be the cause of your flasher issues...


06-12-2012, 08:07 PM
There are several sellers on e-bay with the copper fuses ranging in price from $8 - $20 for a set of them. Search Mercedes fuses

06-13-2012, 03:21 PM
copper fuses are the way to go... The contacts are copper, soooo..put an alloy fuse up against a copper contact-->chemistry does the rest.

I change ALL my cars to copper the moment they roll in..same goes for all my clients. I've gone through thousands of those damn fuses. For a while I was saving all the old ones till I have a gallon sized bag BULGING with old alloy fuses..tossed it in the recycle bin..:-P


06-13-2012, 05:24 PM
Yes - I've already switched all my fuses over to copper. They're $3 and change for a box of 5 at AutoZone. And Dave, all my fuses are the correct ratings. I keep checking to see if one of my window switches is sticking, but haven't caught it yet.

06-14-2012, 04:13 AM
I'll add my +2 cents on copper & ceramic fuses!

Just as Jonathan says; alloy fuses + copper clamps in the fuse box + ambient humidity = corrosion on the contact points.
That results in bad contact, burnt contact points, and at high loads over the fuse it leads to heat build up. If it's plastic fuses they do melt down gradually and lead to failure.

06-14-2012, 06:05 AM
Sounds like maybe the old alloy fuses gunked up some of my contacts, and once I switched them out with copper, I broke the (somewhat fused) connection and now the new fuses aren't seating properly in some cases. I'll have to get in there and clean the contacts to remove any residual corrosion.