Troubleshooting Aux Fan - Page 2 - PeachParts Mercedes-Benz Forum

ah-kay · #16 10-06-2009, 03:10 PM

There should NOT be any heat in the first place if the contact is good. A lot of manufacturers have fuses made of plastic. Using ceramic fuse may eliminate the melting problem but not the heat problem. Good contact is fundamental to any connections, otherwise it will only get worse with burn marks and pittings.

Brian Carlton · #17 10-06-2009, 03:17 PM

Quote:

Originally Posted by ah-kay

There should NOT be any heat in the first place if the contact is good. A lot of manufacturers have fuses made of plastic. Using ceramic fuse may eliminate the melting problem but not the heat problem. Good contact is fundamental to any connections, otherwise it will only get worse with burn marks and pittings.

There's ample evidence on the forum that heat is definitely a result of high current across those fuses. The problem is so bad on the blower motor that M/B has a completely separate shunt to bring the power outside of the box.

Although clean contacts are certainly beneficial, the temperature issue with high current draw is not going to be eliminated.

tangofox007 · #18 10-06-2009, 03:19 PM

Quote:

Originally Posted by phinsup

The odd thing is it doesn't actually blow the fuse it's melting the red plastic of the fuse rather then melting the fuse wire

That's a common issue with aluminum fuses. The aluminum oxidizes and insulates the connection, resulting in an increase in increased resistance and heat. Copper or bronze fuses will substantially eliminate the dissimilar metal corrosion problem.

ah-kay · #19 10-06-2009, 04:13 PM

Quote:

Originally Posted by Brian Carlton

There's ample evidence on the forum that heat is definitely a result of high current across those fuses. The problem is so bad on the blower motor that M/B has a completely separate shunt to bring the power outside of the box.

Although clean contacts are certainly beneficial, the temperature issue with high current draw is not going to be eliminated.

If I still remember my physic from University - heat is generated because there is resistance in the line. Power = I^2R. Power is dissipated as heat or other mechanical form. If R = 0 then there is no heat. Power = I ^ 2 (0) = 0. It could be a million Amp but there would still be NO heat, through the fuse or contacts. In otherwords, the fuse can be made of plastic and in fact most of them are.

Fuses are made of all kind of alloy, I would not limited myself to copper, bronze type of fuses as they are made to specification and it fits the application.

Brian Carlton · #20 10-06-2009, 04:18 PM

Quote:

Originally Posted by ah-kay

Fuses are made of all kind of alloy, I would not limited myself to copper, bronze type of fuses as they are made to specification and it fits the application.

Fuses are made of copper or aluminum.

I would restrict myself to the copper fuses.

tangofox007 · #21 10-06-2009, 05:11 PM

Quote:

Originally Posted by ah-kay

Fuses are made of all kind of alloy, I would not limited myself to copper, bronze type of fuses as they are made to specification and it fits the application.

If you better understood galvanic corrosion, you would undoubtedly come to a different conclusion.

It is interesting that it was you who recommended cleaning the fuse holder. That was a good recommendation, but, if it were not for corrosion, why would it be necessary?

As I recall, there have been plenty of problems reported on this forum which were caused by corroded aluminum fuses. Replacing aluminum fuses with copper ones is a very inexpensive way to prevent potential problems.

my83300cd · #22 10-06-2009, 05:19 PM

Quote:

Originally Posted by tangofox007

As I recall, there have been plenty of problems reported on this forum which were caused by corroded aluminum fuses. Replacing aluminum fuses with copper ones is a very inexpensive way to prevent potential problems.

People used to use aluminum wiring in houses- and the wire got the blame for a fair amount of fires.

rrgrassi · #23 10-06-2009, 05:23 PM

Quote:

Originally Posted by my83300cd

People used to use aluminum wiring in houses- and the wire got the blame for a fair amount of fires.

Aluminum expands and contracts at a different rate than copper, and aluminum oxodizes/corrodes creating a resistance point.

It is interesting to note that the power feed from the transformer to the house is aluminum in most cases.

I did switch all my fuses to copper in the car. Fuse problems ended.

ah-kay · #24 10-06-2009, 05:56 PM

FYI. Most if not all HIGH voltage transmission cables are made of aluminum. If it is good for power to the City, to your house. I really cannot see why it not good in your auto. It is the dirty contact which causes all the problem.

The posts we read in this forum are 'problem' posts. You do not hear success stories like 'I use aluminum fuses and I have no problem' post. I try to help the OP to resolve the heat problem and there is no need for me to debate with anyone on the merit of fuse elements material. You can use anything you can afford to buy, plastic, cermic, copper, bronze, aluminum, gold, silver etc. BUT keep the contacts clean.

280EZRider · #25 10-06-2009, 06:14 PM

Just know that there a few knock-off types of fuses out there - especially on ebay - that appear to be copper. They are in fact plated with something that resembles copper, but under the plating, it's a low grade metal. And of course after a few hours of use, the plating disappears. These are the cheezy fuses with plastic insulators - not ceramic.

tangofox007 · #26 10-06-2009, 06:36 PM

Quote:

Originally Posted by ah-kay

FYI. Most if not all HIGH voltage transmission cables are made of aluminum. If it is good for power to the City, to your house. I really cannot see why it not good in your auto. .

The issue is not whether aluminum is a good conductor of electricity. The issue is with the way that aluminum reacts with other metals it comes into contact with.

Quote:

Originally Posted by ah-kay

You do not hear success stories like 'I use aluminum fuses and I have no problem' post.

Maybe there is a good reason for that!!!

Here are a few words on galvanic compatibility:

http://www.engineersedge.com/galvanic_capatability.htm

ah-kay · #27 10-06-2009, 06:37 PM

Can some one help me to find some of these fuses made of copper, bronze or ceramic for newer cars? So it is a fallacy to believe plastic ones are cheesy ones.

The reason that these fuses are better is because the contacts are shape like a blade. Good contact = no heat. They still pose problems when the blades do not get a tight fit. I know b/c my 300SDL caught fire using one of this high rating fuse. I had a circuit drawing about 50A and the contact was loose but that is a story for another day. I carried a fire extinguisher, of course.

ah-kay · #28 10-06-2009, 10:53 PM

Quote:

Originally Posted by ah-kay

Can some one help me to find some of these fuses made of copper, bronze or ceramic for newer cars?

TangoFox and others? Do they exist or do I have to put up with the galvanic corrosion in my 2001 Town & Country minivan. The fuses have been good for the last 8 years but I am not so sure now.

fruitcakesa · #29 10-07-2009, 08:04 AM

My 240 fan kept melting the plastic bodied fuses, even scorching the card in the fuse box.
I cleaned the fuse holder and switched to ceramic/copper fuses and the problem is gone.

ah-kay · #30 10-07-2009, 11:48 AM

Quote:

Originally Posted by fruitcakesa

I cleaned the fuse holder and switched to ceramic/copper fuses and the problem is gone.

May be I am more inquisitive/logical than others. What fixed the problem? Cleaning the fuse holders, switching to ceramic or switching to copper fuses or all of the above? There are 6 combinations if my permutation math is correct.

May be that is the reason plastic fuses get such a bad rap. It was never the root of the problem but a percieved problem.