Bypass melted fuse with inline fuse?
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Bypass melted fuse with inline fuse?
Now that winter is here I've begrudgingly started to tackle some electrical issues on my new-to-me '90 S4. One of the problems with the car is that there was a lot of oxidation on it, particularly in the CE panel.I went through the panel shortly after I got it and used Deoxit on all of the plugs, but while doing this I discovered that one of the radiator fan fuses (#30) was in the process of melting. Now the plastic around the fuse is slightly melted and the fuse doesn't seat reliably in the receptacle. If I wiggle the fuse the rad fan will work for awhile but the fuse will unseat itself before long.
I know that the best fix is to replace the fuse block with a new (or good used) one, but no one seems to sell them new and all of the people who part CE panels don't want to break then up, so instead of springing for a crazy expensive CE panel I was wondering if just doing an inline fuse would work. I looked behind the panel and there are two wires that seem to go directly behind the #30 fuse--one on the top and one on the bottom. Can I just cut these wires and bridge them with an inline fuse or do I have to do something different? I can't read wiring diagrams very well, so that is why I am asking. Any help would be appreciated!
I know that the best fix is to replace the fuse block with a new (or good used) one, but no one seems to sell them new and all of the people who part CE panels don't want to break then up, so instead of springing for a crazy expensive CE panel I was wondering if just doing an inline fuse would work. I looked behind the panel and there are two wires that seem to go directly behind the #30 fuse--one on the top and one on the bottom. Can I just cut these wires and bridge them with an inline fuse or do I have to do something different? I can't read wiring diagrams very well, so that is why I am asking. Any help would be appreciated!
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I pulled my melted high current block out, cleaned it up, tightened the connectors, then swapped it for another block with less current running through it. The numbers are wrong of course, but it works now. Just make sure you get the jumpered connections right.
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You can do just what you stated, however have you read this excellent How to Thread, it really is not all that hard to remove the CE and do it correctly.
https://rennlist.com/forums/928-foru...nor-block.html
https://rennlist.com/forums/928-foru...nor-block.html
Chronic Tool Dropper
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A prime reason for melting the fuse holders is increased motor current, in this case from tired bearings in the motors. There are "other" fan motors that are almost a plug-in, or you can rebuild yours with new bearings and brushes. Your favorite 928 parts vendors can usually help you either way.
The electrical connections in the fuse holders are removable/replaceable, and are readily available from those same sources or from your neighborhood VW parts counter. Just take the old one with you. There's a little tab formed in the back of the metal connector where the fuse plugs in; depress that tab with a skinny probe and it can be withdrawn from the plastic support. You can clean it and add a little extra tension to it, or just replace it if you have the correct ratcheting crimping tool. Corrosion in the CE manifests obviously at the sockets for the fuses and relays, but that corrosion often extends back into the wire insulation some, making connector replacement the only reasonable option, cutting the wire back until you get to bright copper again.
The electrical connections in the fuse holders are removable/replaceable, and are readily available from those same sources or from your neighborhood VW parts counter. Just take the old one with you. There's a little tab formed in the back of the metal connector where the fuse plugs in; depress that tab with a skinny probe and it can be withdrawn from the plastic support. You can clean it and add a little extra tension to it, or just replace it if you have the correct ratcheting crimping tool. Corrosion in the CE manifests obviously at the sockets for the fuses and relays, but that corrosion often extends back into the wire insulation some, making connector replacement the only reasonable option, cutting the wire back until you get to bright copper again.
Rainman
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A prime reason for melting the fuse holders is increased motor current, in this case from tired bearings in the motors. There are "other" fan motors that are almost a plug-in, or you can rebuild yours with new bearings and brushes. Your favorite 928 parts vendors can usually help you either way.
There are a ton of fan motors (Ford, Volvo for example) that will fit the shrouds with a little tweaking but attaching the blade to the motor shaft is the hard part, I haven't found another motor yet that uses a "pin drive" like the Porsche fans do.
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Have you checked with Mark or Tom at 928 Intl? The 1/2 price sale is on and you might be able to pick up a good used panel for a good price then you can make sure everything is nice and clean and just swap everything over.
Drifting
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From: Northern Virginia
^^^ Do This!
I enjoyed the process of fixing mine, and the rest of my panel is in great shape. If you have a lot of oxidation I'm pretty sure 928 Intl has a better one for ya (Mark posted a pic in the 1/2 price sale thread...lots and lots of CE panels). It's worth having a spare panel.
I enjoyed the process of fixing mine, and the rest of my panel is in great shape. If you have a lot of oxidation I'm pretty sure 928 Intl has a better one for ya (Mark posted a pic in the 1/2 price sale thread...lots and lots of CE panels). It's worth having a spare panel.
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From: Toronto, ON
Thanks for the info guys. I have looked at the threads detailing the fuse panel fix--to be honest I'm just worried about potentially messing up other circuits in the block in case I do something incorrectly, and there is a high probability of that as I am not terribly competent with electrical stuff. I looked at maybe getting a used CE panel at 928 International, and while that would be ideal it would still end up costing me around 500 Canuck-bucks when all was said and done, so with all of those factors combined I thought that putting in an in-line fuse would be the easiest and most cost effective fix. I'm assuming that bridging the two grey wires that appear directly behind the melted fuse with an in-line fuse will do the trick, but I just wanted to confirm that these were the correct wires and they didn't have to be bridged with other wires or something.
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A prime reason for melting the fuse holders is increased motor current, in this case from tired bearings in the motors. There are "other" fan motors that are almost a plug-in, or you can rebuild yours with new bearings and brushes. Your favorite 928 parts vendors can usually help you either way.
While higher currents from a degraded or non standard fan motor may not help in these scenarios - they are not really actually a primary cause here IMO.
Something else went wrong first. I suspect often perfectly good but ugly looking fuses were replaced with bright shiny Chinese specials - that actually have proved to be a disaster for all the above reasons...
Better fan motors may also help but saving those fuse connectors is the most important thing. It's amazing to see how much chemical cleaning and a little physical adjustment can restore perfect function on them, but unfortunately a charred plastic carrier always looks a bit ugly.
Alan
Drifting
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From: Northern Virginia
I think there's more chance of creating a problem trying to jumper it - especially if you have little experience doing electrical stuff. It's easy to make the repairs I described in my CE panel thread. I considered the jumper idea, but decided I'd feel better about the repair itself if I restored the original connections. It's not a difficult job. Do it in small chunks. By the end of it you will know you car much better and removed the fear and mystery surrounding the CE panel. I picked up my used CE panel on eBay for $80 and it included a few #53 relays.
But, if you want to proceed with splicing in an inline fuse... Yes, those are he wires. You will need to remove two screws that hold the top of the CE in place and fold the CE panel down. Then carefully identify the correct wires in the tangle of gray wires on the back of the panel. Then comes the part I just couldn't bring myself to do, pull of the wires from their connections and CUT OFF the connectors... (I have nothing to say about what happens next
)
But, if you want to proceed with splicing in an inline fuse... Yes, those are he wires. You will need to remove two screws that hold the top of the CE in place and fold the CE panel down. Then carefully identify the correct wires in the tangle of gray wires on the back of the panel. Then comes the part I just couldn't bring myself to do, pull of the wires from their connections and CUT OFF the connectors... (I have nothing to say about what happens next
)Thanks for the info guys. I have looked at the threads detailing the fuse panel fix--to be honest I'm just worried about potentially messing up other circuits in the block in case I do something incorrectly, and there is a high probability of that as I am not terribly competent with electrical stuff. I looked at maybe getting a used CE panel at 928 International, and while that would be ideal it would still end up costing me around 500 Canuck-bucks when all was said and done, so with all of those factors combined I thought that putting in an in-line fuse would be the easiest and most cost effective fix. I'm assuming that bridging the two grey wires that appear directly behind the melted fuse with an in-line fuse will do the trick, but I just wanted to confirm that these were the correct wires and they didn't have to be bridged with other wires or something.
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Well, based on everyone's advice I manned up and opened up the front face of the fuse block. I broke a couple of tabs, but now that I know how it works I doubt that I would break any more if I had to do it again. I cleaned up the contacts with Deoxit and pushed the tines together so that the fuse can seat better. I put it all back together and both of the fans run now, so I hope that it stays that way for a long while to come! Thanks everyone for your sage advice. I'm glad I ended up opening it up and fixing it properly.
I have another semi-related issue regarding another melted fuse, but I decided to make another thread so that things would be easier to follow. If anyone wants to chime in over there with any advice that would be awesome. Thanks again!
https://rennlist.com/forums/928-foru...l#post13796899
I have another semi-related issue regarding another melted fuse, but I decided to make another thread so that things would be easier to follow. If anyone wants to chime in over there with any advice that would be awesome. Thanks again!
https://rennlist.com/forums/928-foru...l#post13796899
Drifting
Joined: May 2010
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From: Northern Virginia
Good going Simon. It's hard to avoid breaking or nearly breaking those little hooked tabs...the plastic is 30+ years old. If you did this with the panel in the car...well, you get extra credit What you did should work. I agree the ultimate test is running the AC awhile. Make sure your fuses are Bussman or Littlefuse.
What you did should work. I agree the ultimate test is running the AC awhile. Make sure your fuses are Bussman or Littlefuse.