Buss Fuses - Are they OK?
 

Just replaced the CC blower assembly in my 201. The old one was near about seized up. I'm thinking the old blower placed undue hardship on the blower motor regulator and maybe its on its way out too, because I blew a fuse when I cranked the fan up to full speed. Are buss fuses OK to use in MB?

My '85 was filled with them when I first got it and there are no burnt-out consumers.

However, your vehicle is far advanced from mine and I should not make such great assumptions ; )

I cannot see why Buss type Fuses of the proper amperage and proper Fuse Holder would not work. It might be a Mercedes but Electrons are Electrons.

But, what is wrong with the origional Fuse Holder?

I've never had any issues with Buss fuses. They work just fine.

The fuse holder is fine I think. When I first started the blower, I switched it up to high to test and it ran for a minute or so, I smelled burnt plastic, and then it kicked off. Went to the fuse box, #1 fuse (20 amp) had blown, plastic body of fuse was melted on the end. Replaced with another 20 amp, started the blower on low - fuse seemed fine, switched up to medium speed, put my finger on the fuse and it felt warm, so I ran it like that for a while and it did not burn out, but was warm to touch. I guess I should not expect to use the blower on high for now.

I started thinking that MB does not like bulbs other than OEM spec, so I was wondering if the same went for fuses.

After melting numerous plastic body blower fuses I got straightened out and went to ceramic fuses. End of problem

Thanks - I will try them!

When you say "Buss" I assume you mean glass fuses? They should be OK as long as they make good contact. OTOH, European-style fuses from an on-line seller such as FastLane (supports this forum) will be less expensive, just make sure the base material is ceramic and not plastic, as the fruitcake says.

BTW, a fuse that gets hot is a fuse that is making poor contact and trying to carry a lot of current. Carefully clean the fuse ends and the fuse panel contacts with fine steel wool or emery cloth, then make sure you haven't left wisps of steel wool in place to short-circuit. Dirty contacts are the bane of all fuses.

Jeremy

I wouldn't want to use an open, plastic-bodied design for the high amperage ones purely for personal paranoid safety concerns. And for high amp fuses, an enclosed design will probably blow faster than an open design like the ceramic originals.

Other than that, they should be interchangeable.

Jeremy, good tips - Thanks.
Buss has an aftermarket euro style fuse that looks kinda like the ceramic, but has a plastic body. That's the style I have been using and before the blower seized up, I was going through about a box a month. Now the new blower is smooth as silk, but this hot fuse issue has presented itself. I was thinking either the fuses are crap or I fargled up the blower regulator with the mortally-ill blower.

X2 mine were oxidized looking before I polished them.

You need to measure the current being drawn through the blower circuit. In high speed the blower can draw as much as 25 Amps (some have seen even higher currents) but at lower speeds the current draw should be as low as 5 Amps. If your circuit draws 25+ Amps regardless of blower speed then you have indeed "fargled up" the circuit.

Easiest way to measure the current through a circuit is to remove the fuse from the fuseholder and clip one lead of the ammeter onto each fuseholder terminal. Most DVMs have a fuse in their ammeter circuit so you are still protected. With the ammeter in place, try the blower in various speeds and record the current for the various speeds. You will have to fiddle with the temp dial with the PBU in "auto" fan speed but High and Low are just a button press.

Jeremy

You need to leave the fuse in place to measure amps / current through a circuit, correct?

I think the DVM will act as the "fuse" - just guessing since I don't have a DVM - I don't even have an analog voltmeter. Guess I have to get to HF on payday....

Yes - HF and I are inextricably intertwined. If I get ready to go there - I never tell the wife any more.:wink3: