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Thu Jun 22, 2017 7:51 pm

Hello, I'm winding up my motor rejuvenation, 76 bus with a GD motor. You may remember the thread in which I discovered that I had a broken valve guide. I can't begin to tell you how helpful it has been to be able to access the multitude of articles and (especially) pictures on Thesamba to answer the dozens of questions that have arisen in this process. Plus so many things needed replacing, I would never have discovered all of them without TS.

Before I install it, I need to address the elephant in the (engine) room concerning this vehicle; the melting of wires coming out of the heater fan bundle. (see pic) Call me a dreamer but I think I can make the heat work. I have a sense of where most of these wires went, but I'd like to pinpoint the other ends of them to check for continuity. I understand the wiring diagram in the Bentley manual, but the diagram gives no clue as to where these wires physically exist and what they are bundled with. I can't find any trace of the right half of the red wire with the fuse holder that connects to the starter, although I still have the fuse holder. I may have yanked it in a previous engine pull when I was too lazy to reattach the flapper boxes. Should it have a loop or a female terminal on the end? The brown and white wire is burned through; in a perfect world does it go to the fuse box? Blue wire goes to the oil pressure switch, right? The black wire connects to terminal A of the fan relay and goes on to terminal 15 of the coil, but I had it running directly to the coil and taped off the double connector. That's one I want to check for continuity.

I've gathered from what I've read and from pictures I took that the single blue wire hanging down from the grommet with the female terminal is for the alternator warning light, and the black wire next to it is from a diagnostic system that doesn't exist any more. Let me know if I'm wrong.

Yes, I know my CV boots need replaced.

Thanks so much!

Stella

Thu Jun 22, 2017 9:02 pm

The red wire is going to be the #30 circuit supplying the power to the fan relay.

The black wire is the #15 ignition circuit, it supplies a trigger for the fan relay, but more importantly supplies power to the coil and triggers the FI double relay.

The brown/white wire is a switched ground for the fan relay, the other end goes to a switch on the heater temperature lever on the dash.

The yellow/black wire moves power from the fan relay to the fan.

The '79 is in color and has an index at the bottom so is often the best diagram to use for any Type 4 powered Transporter.

Double click to enlarge

Thu Jun 22, 2017 9:20 pm

Here's a highlighted view of the details, to go with Wildthing's description.
(Note the '76 version is slightly different from the '79 - the relay coil is powered by the alternator D+ terminal rather than the ignition circuit. I think the '79 method is safer, as a circuit issue can't cook the three small alternator diodes.)

Sat Jun 24, 2017 8:47 pm

Thanks so much. I was able to use a piece of wire with a terminal from the diagnostic box (part# 823 971 503- yes, I still have mine!) to complete the brown and white ground wire, it was even the right color. Not the prettiest repair I've done, but it's solid. I ran a wire through a “string tube” (clear plastic tube that violin strings are shipped in) through the grommet alongside the harness and attached a loop terminal for the starter connection. Still not sure what the white and green wire in the bundle is for, I'll have to look under the dash for it. It sure was a lot easier with the motor out. I'm a couple days from trying it out, but I've been working on it since November. There were so many things that either didn't exist (flaps), leaked (throttle gasket, intake tubes), or were in the wrong place, it's amazing it ran at all. I'll be putting up another post soon with some details, particularly with the Corvair thermostat. It's amazing.

Sat Jun 24, 2017 10:24 pm

Hope you repaired/replaced more wires than that. The pic was pretty ugly...