May 24, 2013
This week we faced our biggest challenge ever in this entire build-a-car-from-scratch project. As you might suspect, the challenge involved electricity, and this time it wasn't even our fault. Or if it was, it wasn't intentional. Starting out, all we wanted to do was get the dashboard installed and the gauges hooked up. We thought it would be a good idea to attach the glove box to the dash first, and we were a little surprised when it turned out to actually fit.
We were pretty sure the clearance between the door and the dashboard was so tight we'd never be able to align it properly, and the door would never fit flush with the rest of the dash, let alone open or close. But it looks like holes were made to be enlarged, especially holes in hinges, and after filing enough of the holes down we got the door adjusted perfectly, based as usual on our own definition of perfectly. And adjusted. So now, one twist of our German latch pops the door open, and a gentle shove clicks it shut. Or not gentle, but, you know, gentle for Germans.
So that went well, although we still haven't figured out how we're going to keep things in the glove box from falling out the back. At this point we wouldn't be opposed to a paper bag and a roll of duct tape, but our main concern with that idea is that it might work too well and we'd never get around to replacing it. Of course we could always paint the bag black. And use black duct tape. in any case the glove box isn't necessary to operate the car, so we decided not to worry about it for now.
Before we bolted on the dash we thought it would be a good idea to make some kind of accounting for the huge mess of wires under the scuttle. We only had a dozen electrical components to install, and there must have been at least a thousand wires under there, give or take a few hundred, and so clearly we had extra wires. Some of the wires were insulated, but most were just hanging loose, ready to find some chassis ground and set the car on fire just as soon as we turned the key. That hadn't happened so far, but we hadn't driven the car yet either.
It took some time to get all the wires sorted out. We insulated a few and tie-wrapped the rest, and then checked for voltage in each of the wires that go to the switches, dials, and indicator lamps that we planned to install. Everything looked good except for one little glitch. When we turned on the headlights, the left turn signal indicator lit up. We thought maybe we'd incorrectly labeled the high-beam indicator as a turn indicator, so we put on the high beams. The actual high-beam indicator lit up. The turn signal indicator stayed on.
So we dug out our wiring diagram, and it turned out the headlight and turn signal circuits are about as far apart on the page as you can get, and there didn't appear to be any sort of connection between them. But after staring at the page for half an hour, we finally noticed little asterisks next to the dimmer switch on the left side of the page, and the turn signal switch on the right. In the bottom right corner of the diagram, tiny 3-point type read, "asterisk indicates two switches assembled in one housing". So that was a clue.
According to the wiring diagram, power from the headlight switch goes directly through a blue wire to the dimmer switch, where it's directed to the low beams or high beams by a stalk on the steering column, the same stalk that operates the turn signals. Since the left-hand turn signal was getting power regardless which beams were selected, the problem had to be somewhere before the dimmer switch. Also, since power was going directly to the green/red wire of the left turn signal, bypassing the turn signal switch, that switch was out of the loop as well.
Having ruled out both switches, we naturally thought it would be a good idea to take apart the steering hub and get a look at the switch mechanism, on the off chance we'd find something obvious, like a note from the previous owner telling us what was wrong and how to fix it. But no. Not even a frayed wire or a burned-out connector. Then we tried unplugging the turn signal switch entirely, so at least no power could get from the headlight switch to the turn signals. So of course when we flipped on the headlights, the left turn signal indicator lit up.
That was a little baffling. The only connection between the two circuits was the dimmer switch, and that was disconnected, and yet the circuits were still crossed. At this point we didn't even have any options. So we spent the next several days tracing back just about every blue or green wire in the entire wiring harness, and it wasn't until we got to the left front corner of the car that we found the wire for the left turn signal light and the wire for the left front side marker light taped together.
We're not sure how the wires got taped together. No doubt it happened a long time ago, long before any of us knew anything about automotive wiring. And at this point it doesn't really matter. All the wiring works, all the gauges work, and all the switches work. The fuel gauge is accurate, a nice surprise, and with the temperature gauge working we've found that the car doesn't overheat like the donor used to, at least when it's idling in the driveway. So we're all done with the wiring, and the electrical part of this mission is now officially behind us.
And the end result doesn't look too bad. The gauges from the donor all shined up nicely, and they're easy to see through the big steering wheel. Installing the dashboard, dials, switches, and all the indicator lights comprised seven big steps in our coachwork countdown, leaving us with just 44 steps and 254 hours to go. The aluminum for our body panels has yet to arrive, so to keep busy we're going to work on the bonnet next, cutting holes so it fits over the engine, and then figuring out what to do about the holes.
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