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Old 12-16-2013, 10:58 PM   #258
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Location: Kalamazoo, Michigan
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Re: I suck at reading wiring diagrams..

Originally Posted by Steve-W View Post
I was piggybacking on a other thread, but that became to confusing with the original question, So I have stolen a quote:

3 questions, hopefully not to stupid..why is there nothing mentioned about a starter relais, or is that the "fusible link"? I know there is the solenoid, but isn't it safer to have a relais guide the feed there instead of thrue the ignition switch?
secondly (be gentle) ACC on my ignition switch stands for? Accesories? I see in the diagram it goes to a whole lot of things after the fuse panel, so that only has power with the ignition turned on right?
then it would make sence why there are so many wires coming from the egnition switch as shown on the picture (not the diagram)

last one for now: do I still need the voltage regulator that was mounted left fron next to the headlight?
Ok I'll tell you what the wires are for on the ignition switch you quoted.,and answer your questions .

The large red wire on the top is the battery power wire from the engine compartment. The smaller red wire is for hot power to the horn relay the headlight switch or the fuse panel. They all need key off, hot power for the horn the lights or the brake lights without the key on. The wiring diagram shows them joined in the harness with the large battery wire and only one red wire going to the key switch.

The double brown wire clockwise is for the brake warning light in the cluster and this wire goes from the brake distribution block to the key switch and then to the brake warning light in the dash cluster. It is just a ground connection when the brake block is out of sync between the front and rear brakes. The key switch grounds this wire to the switch body during starting just to test the warning light. It is the ground side of the warning light circuit.

The double green wire next to it is for the temperature hot light in the idiot light cluster and it runs from the idiot light temperature sender in the engine head to the key switch and on to the cluster to the ground side of the temperature light. The same thing happens when the key is turned to start, the key switch grounds this wire to the switch body and completes the ground circuit for the temperature light, just to test the bulb. You may not have this wire if your truck has the gauge cluster and not the idiot light cluster.

The pink wire is for the ignition and goes to the firewall plug where it connects to a resistor wire for the coil and another wire that goes to the starter R terminal ( usually yellow ) that bypasses the resistor wire during starting, to send a full 12 volts to the coil for hotter spark during start. If you convert to an HEI distributor, which requires a full 12 volts all the time, you will not need this resistor wire, or the yellow wire.

The large purple wire is of course the starter solenoid wire. It runs from the key switch to the neutral start switch if you have an automatic and then to the firewall block where it continues on to the starter solenoid. The starter solenoid IS the relay to answer your first question. All the purple wire does is engage the solenoid, and the solenoid contacts energize the starter

The large double brown wire should be the accessory wire terminal. The larger brown wire goes to the fuse panel and feeds the turn signal and hazard light flashers and the power wires for those circuits which I pointed out in my post above about the half moon connector. The other brown wire should be a 10 ohm resistor wire which goes to the firewall block and then to the external voltage regulator.

The ACC terminal has power when the key is in the ignition position and also when it is turned to the ACC position. There the ignition circuit is cut out of the power loop to prevent the coil from burning up.

You still need the external voltage regulator unless the harness converts your alternator to an internal regulated style, or you do it yourself.

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