Quote:
Originally Posted by VetteVet
When your truck came from the factory it had points in the distributor and an ignition coil that would not sustain a constant 12 volts to it. The factory solved this by installing a 1.8 ohm resistance wire in the firewall terminal block to drop the voltage to the coil for normal running. This wire was a white/orange/purple wire which is shown below as a cloth covered wire and over the years has turned mostly white.
Attachment 1625034
The factory also wanted to get a full 12 volts to the coil for a hotter spark when starting so they installed a connecting wire from the starter "R" terminal which was a yellow or yellow with a black stripe wire to achieve this purpose.
When HEI ignition was added the distributors needed a full 12 volts all the time when starting and running. They eliminated the resistance wire and the connecting wire from the starter.
This diagram shows the resistance wire and the connecting wire on the middle of the diagram and on the top by the starter.
Attachment 1625035
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Unless someone needed another purple wire from the ignition for some unknown purpose there was only one 12 ga purple wire on the key switch.
It ran from the ST terminal on the key switch to the NSS on the steering column (automatics) to the firewall block and on to the starter solenoid.
The only 20 gauge wire on the key switch is the brake warning wire, which runs to the switch and joins another 20ga tan wire, that runs to the dash cluster to the brake warning light. When the key switch is turned to start
a circuit in the switch grounds this tan wire and turns on the light, to test the bulb, to check that it isn't blown.
whenever the fluid levels in the brake distribution valve gets uneven a switch in the valve will ground this wire and turn on the light. |
I see, that resistance wire is on the RH (truck side) of your terminal block. You have five wires, and I do as well. Here's what I've got:
1. Purple12 to Starter
2. Brown/White 18ish for TCS
3. Dark Green20 for Temperature Sensor
4. Tan20 for Combination Valve
5. Looks Light Red 18-20 AWG, but I think it's a safe bet it's Pink. A picture is below. The kicker is it says Resistance on the wire. Perhaps it was a replacement, but safe to say this is the wire I was "missing".
Thing about it is, and yeah I'm slow................I have HEI, and this "resistance" wire was connected to my starter. Anyway, WOW, you're saying this is incorrect right? it should be removed. I'm surprised it's worked for so long with no problems, but that said, I think I just got a clue why the image above (Post 7 Image 1) for Pink appears to be missing a connection..............Do you agree?
Also, concerning "option 1 for HEI", are you saying to replace this resistance wire with a 12 AWG for HEI?
Concerning the Purple Wire (a.k.a. ST, SOL). Either I misread the posts or am just plain green on the subject of wiring. As you're probably aware by now, it's likely the latter. Takes me a while sometimes, but I get there eventually. Thank you for clearing that up. I'll update the image at top and put the Ignition Switch to rest. Appreciate your help and patience.
