67 key Switch- No 12Ga Brown Wire?

[Spidermonkey]

I am looking at hooking up a keyless entry push button start in my 67.
I have a wiring diagram and it shows a 12ga Brown running from the key switch to the fuse block to power up backup lights, blower fan and wiper motor. On the back of my keyswitch and harness to the fuse block there is no 12ga brown. Only the smaller brown/white for the external voltage regulator. Did some Base c10s not use this wire and those circuits are powered through a different method? I am just trying to figure out how power is switched on to those circuits. The key switch and harness only have the Red for power to the switch pink to the coil, 2x Tan and 2x green for the grounding dash lights, purple to the starter and the brown/white for voltage regulator. I can't imagine that all the power is sent a long that small gauge brown/white? What am I missing? Harness looks untouched. Only think I can think of is the pink is also powering that circuit...

[pjmoreland]

I'd say this warrants some investigation. Here are a couple of ideas:

1) There is a thread somewhere on this forum where you can download PDFs of service manuals. Also available on the same thread are electrical manuals for specific years. Get the 67 electrical manual and scroll through it to find the specific diagram for your truck

2) Detach your fuse panel from the firewall and look at the back of it to see what color wire is powering the things that the brown 12 gauge wire usually powers.

[Spidermonkey]

Thanks. I'm going to try option 1.
I was hoping to avoid option 2 lol.

[pjmoreland]

It's really not that hard to pop the fuse panel off the firewall. Detach the bulkhead connector in the engine bay, remove the two screws that secure the fuse panel to the firewall, and then it pulls away from the firewall. Then you can pry the bulkhead connector off the back of the fuse panel and take a look.

[Spidermonkey]

Ok great. I'll rake a look tonight. Probably a good time to look at it and make sure all is good anyways. That harness could need some love. Bow would be tge time to address anything.

Thanks

[dmjlambert]

The generic 67-72 wiring diagram shows that 12 gauge brown wire in the cab is for the accessory section of the fuse panel, and comes from the key switch when it is in the accessory or key on position. But 67s do not have an accessory key position, they only have off, on, and crank. So that accessory part of the fuse panel is getting power from the on position of the key switch and pink wire. The diagram is on page 12-41 of the service manual, I recommend get a paper one, they are cheap and reproduced. PDF here: http://67-72chevytrucks.com/vboard/s...d.php?t=558016
I recommend plugging into the fuse panel at a position that gives you switched power for accessories that require switched power, or plug in at a position that gives always on power for accessories that require always on power. On these trucks I believe that would be the CIG position for always on, which is unfused, and Radio, SPOT LP and IGN UNFUSED for switched power. Use an inline fuse if you plug in to an unfused terminal.

[pjmoreland]

I totally forgot about that! I even owned a '67.

[Spidermonkey]

This is amazing Information. Thank you. This makes a lot.of sense now. I think what I may do is seperate the items I need on ACC. If I wanted to make it simple.I could just run the pink wire to the ACC and then it would operate the same as it does now.

Thanks again..

[Spidermonkey]

Anyone happen to know how many amps are drawn on that pink wire in factor form? Or if a newer blower motor replacement happens (non ac)? I am just wondering if I should be using a relay instead of running this through the start module. I think k tge module is rated for 30A. However, there is only 14Ga wires on it. I am thinking I better use a relay. The good news is the ignition/ coil circuit is removed since its an LS swap so the 12v ign wire is simply co trolling a relay. I really need to know wiper motor and blower fan combined.

[dmjlambert]

I don't know the amp draw of the blower motor, but I think it is quite a lot as it is common for the blower switch connector and/or ignition switch connector to be melted in these trucks. I think the wiper motor would be quite a bit less. I recommend using a relay to protect that fancy new equipment you're putting in, especially since it has 14 gauge wires on it. For some years now the only replacement blower motors are for A/C and they are sold as universal "Blower Motor A/C or Non-A/C Equipped". So a replacement heater blower in your future will be an A/C motor and it will draw a lot more current. The non-A/C trucks do not have a high speed blower relay the way A/C trucks do, so it puts even more stress on the speed switch and wiring for the speed switch in a non-A/C truck.

[dmjlambert]

Here's an old post talking about the current and forum member GMC Jim gave the figures.
http://67-72chevytrucks.com/vboard/s...380#post597380