Quote:
Originally Posted by jbgroby
OK, so the power leads from the lights go to the headlight switch/re-o-stat. the main power for the gauges goes to the ignition. Ok I got it now (I hope). the headlight switch did not come with any instructions or diagram for the pin connector.
The unit looks like this. any ideas where to tie in the leads? How did you fine fellows do this?
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I don't know how the fine fellows who actually know what they are doing go about it: I tend to get bent up like a pretzel under the dash and start chasing wires through the maze, grateful it is only 12 Volts.
Thanks, Pasadenajim, for pointing out the obvious regarding instrument lights being tagged into the headlight switch rheostat. I've been scratching my head as to why the Maintenance Manual's Electrical Circuit Diagram shows the instrument cluster's instrument lamps being fed from the fuse block's top fuse (on the fuse's right side).
Well, after following what seems like miles of spaghetti in the electric circuit diagram, I see the other side of that fuse is fed from the light switch (contact 5) by way of a 16 ga. black wire, which I assume runs through the headlight switch rheostat (the diagram doesn't show much of the internals of the headlight switch).
On wiring the light switch: attched is a photo of the same "Electrical Circuit Diagram--Series 1000 Thru 3500 With Turn Signals" from "GMC Trucks Maintenance Manual, Models 1000-5000". I cropped and took out lots of the diagram to make it easier for me to understand the light switch wiring without getting my eyes crossed to much. If your wiring follows the original colors, it might be easy to find what goes where on the light switch. If your wiring is like mine, it will still be a hunt.
One thing that surprises me is there seems to be no fuse protection on the positive side of the wiring to the light switch. The 14 ga. red wire that feeds the light switch (contact 4) comes from a splice connected to battery plus by way of a terminal on the starter solinoid. I can't see any fuse in the path. That has me thinking about putting in a fuse or a shut off switch for some protection in case of a short.
Hope this helps,
Culver Adams