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I have a 1989 928. I had brought it to my mechanic as the pull switch by the drivers door floor was not opening the rear hatch. Also, the fog lights would not work.
He found what looks to be like a burnt fuse panel and we're not sure where to go from here. Does the whole panel have to be replaced? Can just the module with the 5 fuses be replaced? You can see the burnt area between the two 30 amp fuses.See pic
^^ Get the section you need from Mark and install it. You only need to replace that 1 module. (they're all different so you need that exact one for your year)
Most likely what happened is there is some corrosion on the fuse contacts which caused resistance that melted the plastic.
Go through your entire fuse panel and clean all contacts with a good contact cleaner like Deoxit 100 to prevent any further damage.
Look on the forum for how to pull the whole board out.
Once you have it out you can inspect it better for damage.
You should clean and refresh the entire board.
The damaged block can come out independently.
Tool of choice staple remover- flat end with plastic handle
There are many other threads on this. Most importantly understand that inside the fuse blocks (even of the same numbers) the terminal configurations can be different by year - various of the top (input) connections are shorted together (sometimes all 5). This is not different for every single year - but there are many configurations. Best to take the front cover off the old and & the replacement fuse block to verify visually (or do it electrically). In any case you need to evaluate that the terminals are clean and tight on the replacement panel. The terminals can be swapped around if you have spares of the kinds you need.
Those look like the fan fuses. The contacts may have corroded or loosened over time, leading to heating and arcing, and loss of electrical continuity. Once you have it apart you can inspect and see if you can salvage what you have. Look at the backside of the fuse sockets, and check the condition of the copper spring that holds the fuse. You may find that the copper contacts that hold the fuse can be cleaned and bent to restore tight grip on the fuse.
Also ask yourself whats on those 30amp circuits and look for another possible reason of heat build up.
There is no point looking elsewhere - the only thing that causes this is a high resistance connection between the fuse and fuse-holder. The heat does not come from the fuse element - it comes from the terminals.
The fuse element will still be good - unless it is mechanically ripped apart by the thermal damage to the plastic body.
I can guarantee that while this fuse was melting the current in the circuit was Lower than it should have been NOT Higher. Its important to understand the primary resistance build up mechanism. Yes this does happen mostly on high current circuits - because their normal current is frankly a bit too high for this design of fuse-holder (the contact areas are too small) - works OK when its in perfect condition - but once they start to degrade they will continue to deteriorate. Dampness getting onto the panel is often the starting point for degradation - but even using poor quality fuses can be enough to start this failure process.
Use Bussman or Littelfuse brands for ATO/ATC fuses - cheap Chinese fuses often have many issues with poor terminal dimensions, wrong plating material, and poor adherence to ratings. For the OP case the fuses look to be good - but its hard to be sure. Good quality fuses do not have gold plated terminals - if you have fuses that look like they are gold plated: 1) They are not - and 2) you should throw them away and get good ones.
Yeah I know what you are dealing with. Been there, got the shirt. My 88 melted the two 30 amp fuses into a goey mess, that gave a "pop" and smoke from the floorboard. Most likely cause was the cheap *** OReily fuses I put in there not knowing what garbage they were. Also don't overspray Deoxit across the plastic parts. Be sure to only hit the metal. Not sure if it matters, but I was **** about this after this mishap. To fix this problem I got a replacement used CE panel from 928 Intl. I thoroughly cleaned it with emory boards and dioxit (followed a write up on the board here), put all new relays and fuses into it (only buy from Roger or OEM source). Installed the new board and its been problem free since. I didn't replace just a cube of the fuse holders....have you seen the grey spaghetti back there?....way over my abilities....and I wanted to kill the problem dead and not create a future problem. Good luck!
Brian
07-12-2021, 06:43 PM
1989 S4 burnt fuse board?
