Fusebox Post-Mortem
Discussion
Had to replace a customers fusebox which was suffering from corrosion.
So, I decided to carry out a post-mortem on the Fusebox to try and understand the issues and if repair would be cost effective as this will happen more in the future and replacements will turn into ‘Hens Teeth’.
There have been threads in the past suggesting that an Audi ‘box is a replacement but whilst it looks the same from the outside it is different inside. TVR Parts have it listed on their site but say significant wiring changes are required. It is also out of stock.
I carefully broke open the ‘box which is only solvent glued around the edge of the back face. The construction is a layer of formed brass contacts, a plastic divider layer, another layer of contacts, another plastic etc. In all there are 5 lumps of plastic, the front/main housing, the back and 3 divider layers. There are 68 brass parts.
The brass parts are bare (not plated) so not surprising there is plenty of corrosion with the most significant being one strip that takes the output of the ignition relay to supply fuses 15-18. Many other contacts (mainly the bottom row of fuse contacts) are also corroded and water marking on the plastic parts would indicate it is not liking a possibly damp location or at the very least condensation.
I’m going to experiment with trying to chemically clean the contacts. Soaking in Coke has been suggested but if anyone has a better chemical let me know. If I can find a chemical that works it may be possible to soak the whole box (for however many hours it takes) then rinse and dry but you would need to know that the chemical process had stopped after the rinse cycle. There is nothing else in the ‘box but brass and plastic.
The Coke cleaning is working on some test samples but has taken 20 hours so far and is not yet complete. I will also look at soda blasting the contacts as most of the corrosion is just on the contacts and the remainder can be left alone.
Another possibility is to get an Audi Fusebox and reverse engineer it to find out how many wires need to be moved as it is fairly easy to remove/refit the contacts in the connectors at the back of the box. This may prove to be the most cost effective way to solve the problem.
A few days ago I found some threads which pointed to the part number of the most suitable Audi box but I've looked again and now cant find now find them (was using a different PC) so if anyone has these numbers that would be great as we also found one on ebay for £10.
More to follow
Steve
So, I decided to carry out a post-mortem on the Fusebox to try and understand the issues and if repair would be cost effective as this will happen more in the future and replacements will turn into ‘Hens Teeth’.
There have been threads in the past suggesting that an Audi ‘box is a replacement but whilst it looks the same from the outside it is different inside. TVR Parts have it listed on their site but say significant wiring changes are required. It is also out of stock.
I carefully broke open the ‘box which is only solvent glued around the edge of the back face. The construction is a layer of formed brass contacts, a plastic divider layer, another layer of contacts, another plastic etc. In all there are 5 lumps of plastic, the front/main housing, the back and 3 divider layers. There are 68 brass parts.
The brass parts are bare (not plated) so not surprising there is plenty of corrosion with the most significant being one strip that takes the output of the ignition relay to supply fuses 15-18. Many other contacts (mainly the bottom row of fuse contacts) are also corroded and water marking on the plastic parts would indicate it is not liking a possibly damp location or at the very least condensation.
I’m going to experiment with trying to chemically clean the contacts. Soaking in Coke has been suggested but if anyone has a better chemical let me know. If I can find a chemical that works it may be possible to soak the whole box (for however many hours it takes) then rinse and dry but you would need to know that the chemical process had stopped after the rinse cycle. There is nothing else in the ‘box but brass and plastic.
The Coke cleaning is working on some test samples but has taken 20 hours so far and is not yet complete. I will also look at soda blasting the contacts as most of the corrosion is just on the contacts and the remainder can be left alone.
Another possibility is to get an Audi Fusebox and reverse engineer it to find out how many wires need to be moved as it is fairly easy to remove/refit the contacts in the connectors at the back of the box. This may prove to be the most cost effective way to solve the problem.
A few days ago I found some threads which pointed to the part number of the most suitable Audi box but I've looked again and now cant find now find them (was using a different PC) so if anyone has these numbers that would be great as we also found one on ebay for £10.
More to follow
Steve
What a fantastic post.
I have nothing to offer other than humble support and applaud this kind of effort in a very important area.
Wet footwells must have been the Bain of many an owner when cars were fairly new and leaking already so this might be better or worse dependant on the cars life.
A real problem lurking in the dark and something I’ve thought about in the past, leaks solved and a different Ecu so barely any wiring in footwell on my car and it’s now very dry thank god!
I have nothing to offer other than humble support and applaud this kind of effort in a very important area.
Wet footwells must have been the Bain of many an owner when cars were fairly new and leaking already so this might be better or worse dependant on the cars life.
A real problem lurking in the dark and something I’ve thought about in the past, leaks solved and a different Ecu so barely any wiring in footwell on my car and it’s now very dry thank god!
https://www.youtube.com/watch?v=XhMwjpsvT5k&t=...
recently posted it already in the Chimarea forum, but in another thread
recently posted it already in the Chimarea forum, but in another thread
Various internal links can be taken from older model VW Golf, Passat and Scirocco (perhaps some models of Polo)
the problem is that once those links have corroded or the polished finish has been removed from them they do corrode much quicker in the future if any moisture does get at them
the problem is that once those links have corroded or the polished finish has been removed from them they do corrode much quicker in the future if any moisture does get at them
Hi All, I used this
http://tvr.dspen.com/fusebox/mo264.html
for working out the pins and wires for a fusebox replacement. If you have the bible or the tvr handbook its relatively easy to replace for the modular type
http://tvr.dspen.com/fusebox/mo264.html
for working out the pins and wires for a fusebox replacement. If you have the bible or the tvr handbook its relatively easy to replace for the modular type
Have not found anything conclusive for cleaning the brass ( Coke, vinegar, soda blast) so will ask again if anyone can suggest a chemical/acid that will strip the corrosion from the brass?
In the mean time I have bought an Audi fusebox and will buzz it out and find out how different it is to ours.
Steve
In the mean time I have bought an Audi fusebox and will buzz it out and find out how different it is to ours.
Steve
I have heard that HP Sauce works (doubtless any vinegar-based condiment would) and its thixotropic qualities means that it will brush on and stay put.
Or if it's proper acid you want, 'Spirits of Salts' (hydrochloric acid) is readily obtainable for de-calcifying toilets.
Just don't get caught carrying it if you're riding a scooter...
Or if it's proper acid you want, 'Spirits of Salts' (hydrochloric acid) is readily obtainable for de-calcifying toilets.
Just don't get caught carrying it if you're riding a scooter...
Edited by TwinKam on Thursday 16th May 13:39
Adrian@ said:
Steve ..I do not think Wickes sell it any more...used for 20 plus years for cleaning fuse boxes, switches and motor parts I rebuild.
(contains 1% alcohols, 0.7% cationic surfactants)
Thanks Adrian(contains 1% alcohols, 0.7% cationic surfactants)
A search on cationic surfactants finally mentioned fabric softener. Low and behold the 'Lenor' I use contains 5-15% cationic surfactants so the next test piece is now having a bath.
Steve
ETA spirit of salts ordered
Edited by Steve_D on Thursday 16th May 21:24
davep said:
spikep said:
Good diagram! Which drawing application did you use?Steve, I have spent a little time looking for a replacement for the Wickes version which I purchased a couple of years ago to no avail. THAT SAID, this was near useless for cleaning anything that it was listed for! BUT, one of the things I have advised M series owners (over the last 30 years) is to treat the fuse box as a major service item and have a spare to swap into the car (chemically cleaning the old unit ready for the next major service) SO I do 100% know it does it's job on fuse boxes. A@
Just finished buzzing out the Audi fusebox.
Now have to work out how to re-wire and make it work.
Looking like 1 relay to move position.
Less than 10 wires to move.
A few fuses will have different functions.
Can see why those who tried a swap before said they were not compatible. The horn would be on permanent, dip beam relay would have no supply, Fan2 relay would have no output etc.
A little head scratching to do.
Steve
Now have to work out how to re-wire and make it work.
Looking like 1 relay to move position.
Less than 10 wires to move.
A few fuses will have different functions.
Can see why those who tried a swap before said they were not compatible. The horn would be on permanent, dip beam relay would have no supply, Fan2 relay would have no output etc.
A little head scratching to do.
Steve
Gassing Station | Chimaera | Top of Page | What's New | My Stuff