I finally found the ghost that's been living in Keith's Beetle, and it's my fault. The power feed to the VR has been suspect all the time but not failed at a time when I could check it. Keith said at times the car would die and have only 6v available at the VR but most of the time would be fine, but unfortunately I could not duplicate the concern. I had him come down to the shop for some thorough testing of this circuit, I connected a headlight (2 amp draw) to the circuit and it was fine so I connected a blower motor (9 amp draw) to the circuit for some voltage drop testing. With the blower motor connected I was only getting .11v drop on the circuit which is just fine. I jacked the car, put it on a stand, removed the 13mm nut on the starter and power feed located there which feeds the VR. It looked fine visually and was tight to the touch when pulled so I thought it was OK. When reinstalled and loaded again the power dropped out to the MaxiFuse holder! I thought it was a problem in the fuseholder itself but it turned out to be a problem at the crimp eyelet I installed on the 10ga at the starter. As I moved the wire around on the eyelet the blower motor quit working!
A few months ago my hardware bins were getting low so I had Fastenall refill all of them. I asked for regular crimp connectors with heat shrink tubing and that's what most of them were. Unfortunately they crossed part numbers on one terminal, giving me a low temp solder terminal with heat shrink instead of a crimp terminal. I've always hated the low temp solder connectors and seen troubles with those before because they are built to be heated and the solder melts before the shrink tube does, supposedly connecting the wire and eyelet with a great soldered joint and heat shrink around it. Unfortunately, you cannot visually confirm the solder melts because the tubing has shrank. Visually they look almost identical unless you look into the inlet area. I had assumed I was using a crimp connector and crimped it, and only heated it enough to shrink the tube. Had I heated it more, the solder "might" have melted and not had a problem, but I assumed it was the crimp connector I paid for.
Once I replaced the connector I'm sure this problem is behind us.
This is the eyelet I'm talking about with the 10ga red wire that feeds the VR on the right. The wire on the left is the starter trigger.
This is the other end of that wire that feeds the MaxiFuse and VR.
These are my bins of insulated terminals, I have 3 more bins of non-insulated terminals.
These eyelets look the same at a glance and even have the same writing on the insulation....
Until you look into the inlet and see the one on the left is not a crimp but has a small piece of solder foil in it.
Here's the bastard that I cut open to find the solder not melted and arc marks where it was breaking connection.
My bad, but I'm going to bitch up a storm to Fastenall. I don't know if they were mis-boxed or mis ordered, but you know I'll be looking at every frigging connector I use the rest of my frigging life....
As for the amp load on this circuit I have a oscilloscope capture somewhere from my Ghia years ago when I was curious about the exact amp load on this wire. A long time ago I checked it with an amp clamp to see what the load is, but a scope is more accurate as it catches quick spikes better. About 5 years ago I used my low amp clamp and a PicoScope to find the load was under 10a and spiked to about 28a for a few milliseconds when the starter was engaged. That's why I've always used a 40a fuse without issues. I could use an ATO (smaller automotive style fuse) but never liked those on higher amp loads, so I've always used a MaxiFuse on this circuit because I like overkill.
As for the VR that was replaced, it's probably good but we'll leave it alone. I used an air grinder to not only sand off the paint on the body but also the bottom of the VR where it mounts, it was all perfectly clean bright metal when inspected. I used self drillers to mount the VR but put the last torque on them by hand because the drill will frequently strip them out if you're not careful. Even if Keith could move the VR under pressure because I didn't tighten then screws tight enough I doubt highly it was not properly grounded.
Live and learn.
Pity the poor bastard at Fastenall when I go in there.
