Hello Everyone
If you have electrical problems or gremlins on any vehicle, here are the first three generic steps.
#1. Test the battery.
#2. Test the alternator.
#3. Replace all vehicle fuses with NEW, do NOT test them!

Now you are ready to go on with the serious diagnostics.
Roughly three of every ten vehicles with electrical problems or gremlins are fixed in the first three steps; you could be one of the lucky ones.

Have a great day.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Why shouldn't fuses be tested? Come to think of it, how could one test a fuse anyway? Check resistance, perhaps?

__________________
1982 300D, black w/ palomino leather, 203K
2001 E320, champagne, 105K (Mom's)
1999 Dodge Dakota, squeaky & battered, 142K

Most of the fuses on these vehicles are of aluminum. Over time they corrode and develop cracks that you may or may not see.

For $12.00 or so, Roy suggests that you replace all of them and be done with it. Use fuses made from copper or brass.

It's cheap insurance.

Fuse Testing Methods

Non-destructive testing used by consumers

Look at them. If the center wire has not melted, it's probably not 'blown.'

Check with an ohmmeter. If it measures low resistance, it's not blown. If it has really high resistance, it is open.

Destructive Testing used for Quality Control
Run current through a fuse, and record the current when it melted.

You can't easily measure to predict when a fuse will melt, but you can predict its melting current by trial and error, then employing close tolerances on metallurgy and thickness of the element.

Any open circuit, whether from a melted fuse element, a broken connector, or corrosion between two metals, will prevent current flow.

Best Regards,
Jim

in engineering and the field:
The aluminum changes composition over time.
Fuses are made from a low quality material, and procured from the low bidder.

Here is a random selected source for fuses made from copper or brass.
http://www.jbugs.com/store/merchant.mvc?Screen=CTGY&Category_Code=1134

Here is the search used to find this source.
http://www.google.com/search?q=VW+fuses&hl=en&lr=&start=10&sa=N

$1.50 for 10 fuses!!

I just bought 40 of them.........too good to pass up.

Thanks, Roy!!

Battery to chassis and chassis to engine ground straps probably should be added to this. Some of the electrical problems I have had in the past, with very strange symptoms, was due to the engine ground strap.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

After receiving numerous emails and private messages, I have found it necessary to edit the original post to reflect that I am not the one selling these fuses, nor am I affiliated or connected in any way with the seller. The seller's name is Mombo. I simply copied his ebay listing and posted it as a potential source for fellow forum members to consider when pricing these fuses. Sorry for the confusion.


This is a better price and cost on shipping if you're willing to buy in quantity.




40 PIECES OF GBC CERAMIC OEM STYLE FUSES FOR YOUR EUROPEAN CARS . 10 EACH OF 5 AMP,, 8, 16, 25, AMP. YOU CAN MIX THEM UP ANY WAY YOU WANT IN PACKS OF 10 TO TOTAL 40 PCS. THEY ARE ALL NEW MADE IN GERMANY BY FLOSSER. $6.50 +$3.95 SHIP
HERE IS MY WHOLESALE PRICES FOR YOU VOLUME PLAYERS.THEY COME IN PACKS OF 20.
• 100 PC 9.25 CENTS EA= $9.25 + $3.95 SHIP
• 200 PC 8.5 CENTS EA= $17.00 + $6.95 SHIP
• 500 PC 7.75 CENTS EA= $38.75 + $9.75 SHIP
•
• .YOU CAN ALSO MIX THESE ANY WAY YOU WANT. IN PACKS OF 20. ALSO. ANY QUEST E-MAIL ME OR CALL 732 262-4459 IF IM NOT THERE LEAVE A MESSAGE. THANKYOU MOMBO

__________________
1986 300SDL
1988 Monte Carlo SS
2002 Avalanche
2003 100th Anniversary H-D Dyna Wide Glide

Agree 100%, this is my today experience:

I bought a 1990 W124 sedan recently. The car is fine, but a strange electric problem was present: when I turned on the main light beams, the windshield started.

Before changing the combination switch I checked the relay, resolder some dubious connections. Nothing changed with the windshield wiper.

After that, I cleaned some fuses with contact cleaner. New electric problems arose: now windows open only, didn´t close, unless I open a door (crazy).

I looked the fuses again, now with my glasses on, and discovered that they were very old and almost all have their pins extremely worn, so making bad contacts.

As there where 4 spare fuses in new condition in the fuse box, I swaped them for the ones I had cleaned (and moved) and voila!, problems dissapear.

My conclussion and advice to all W124 owners is: before panic, before changing expensive electric harnesses, before changing relays, before changing combination switches, go simple: CHANGE OLD FUSES FOR NEW ONES.
You will be happy.

Folow whunter advice !

OldBeaver

I believe mostly aluminium is used to make fuses of these which gets cracked over the time. I bought some from Classic VW parts and they were quite good comparatabily.

Non destructive testing could be a known load about half or so of the fuse rating as see what happens.