Ignition Switch and New Harness

[The Rocknrod]

My new wiring harness has a brown wire that feeds power on the fuse panel for the turn signal circuit, wiper.
The Harness also has an Orange wire for the ACC feed and a pink wire for the ignition.
These wires were inserted into connectors for a column type ignition switch when I received the harness. I switched them over to the dash type ignition switch shown.
I’m using a dash ignition switch from a later model like a 68 or 69 which has a ACC terminal.

Top red wire is power wire from engine bay, just below is red wire, it is full time hot also.
clockwise 2 brown wires are for the brake warning light. I do not use that on my brake system.

Two greens are temp sensor light - These are not used on my gauge cluster with a temperature gauge.

bottom pink is the ignition wire to the cab side of the firewall block to the distributor. It also feeds the fuse panel (I think).

Purple wire is starter solenoid wire no problem there.

In the picture shown the larger brown and smaller brown at 10 o*clock are the accessory terminal wires. The large one goes to the fuse panel for the flasher power, heater fan, wiper motor and the smaller one “normally” goes to the inside of the cab firewall block and on to the external voltage regulator, except I’m using a 3 wire internal regulated alternator.

Here’s the rub:
Mine are Large Orange and Small Brown. Titled as Ign Switch ACC feeds fuse panel ACC, Wiper, gauges.
Small Brown feeds fuse panel Turn Signal, Radio ACC Heat. They are not terminated together so I plan to make both of these mimic the browns shown in the pic and plug them into the same spot as the browns shown in the pic. Am I screwing up?
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[The Rocknrod]

Also I don't have a Ammeter anymore it's a volt Meter. My Oil Gauge and sender is now electrical.
New Harness:

[The Rocknrod]

Look what I just found. Exactly what I was planning -
http://67-72chevytrucks.com/vboard/s...8&postcount=35

[VetteVet]

Originally Posted by The Rocknrod

Look what I just found. Exactly what I was planning -
http://67-72chevytrucks.com/vboard/s...8&postcount=35

Hey I see you posted over here in electrical. The harness you have will have to be sorted out so that you know what wires will feed what circuits. The linked thread tells you what happens if you use the orange wire like you were planning.

Does it also show you how to convert the alternator to the three wire that you are using? Is the small brown wire on the Acc terminal the resistance wire that I described in PMs?

These two diagrams are the same but show the wiring a little differently.

The brown/white stripe wire is the very top one on the key switch and the red and pink wires are shown going to the fuse panel on the bottom.

Does the orange wire you have go to the fuse panel?

[The Rocknrod]

Yes the orange wire goes to the fuse panel labeled as as Ign Switch ACC it feeds fuse panel ACC, Wiper, gauges and such.
I'm going to lay the engine bundle out again in a bit I think I saw a resistance wire for the alternator. I am using a 3 wire.
Also your PM's are full.
Thanks

[The Rocknrod]

Yep in the engine bundle of wires there is indeed a white wire for Alternator Tickle and it goes back to the fuse panel, I think it's on the same bus as the orange ACC wire.

[VetteVet]

Originally Posted by The Rocknrod

Yes the orange wire goes to the fuse panel labeled as as Ign Switch ACC it feeds fuse panel ACC, Wiper, gauges and such.
I'm going to lay the engine bundle out again in a bit I think I saw a resistance wire for the alternator. I am using a 3 wire.
Also your PM's are full.
Thanks

If you have the resistance wire you can run it from any key on hot source straight to the alternator no.1 terminal ( SI series), and run a full time hot to no. 2 terminal, then run the alternator output wire back to the main wiring junction and the charging circuit is complete.

If you use the CS style, then you run the resistance wire to the L terminal on the alternator, and you have to add a resistor in the wire, since the 10 ohms resistance isn't enough for the CS alternators. they need at least 35 ohms. Painless wiring recommends 85 ohms/5 watts, for their harnesses. Some guys have used as high as 300 ohms and 1 watt with no problems.

The no. 2 wire is for voltage sensing and charging the fields in the alternator. It should be connected to the main junction with the rest of the loads on the truck.

I have posted my diagrams many times but just in case someone hasn't seen them here is the way I convert to the internally regulated alternator.

12 SI





CS130/144.





Yeah I have trouble keeping my PMs down, I like to hold them because I get a lot of repeat questions. I'll trim them down today.

Originally Posted by The Rocknrod

Yep in the engine bundle of wires there is indeed a white wire for Alternator Tickle and it goes back to the fuse panel, I think it's on the same bus as the orange ACC wire.

So you have a fuse panel with the harness. That was the other variable I thought of when I mentioned that you needed to know what you had that was different from the stock harness.

I think you can go ahead and use the orange wire to the new key switch and it should work just like the 68 and later trucks. You should also use a 10 or 8 gauge wire for the alternator output wire to handle the increased output from the alternator.

[The Rocknrod]

Thank you for that information. But here's another thought/question.
What if I put the brown wire that goes to the fuse panel (that I was going to attach to the orange wire) and put it where the 2 brown wires are for the brake warning light are? Or do they only get hot when in the crank position?

[VetteVet]

Originally Posted by The Rocknrod

Thank you for that information. But here's another thought/question.
What if I put the brown wire that goes to the fuse panel (that I was going to attach to the orange wire) and put it where the 2 brown wires are for the brake warning light are? Or do they only get hot when in the crank position?

NO NO NO remember I said that the key switch grounds the green and brown wires on the key switch when it is turned to START.

Do you know what the brown wire is for? If they meant for it to be for the brake warning light then it would run to the key switch from the master cylinder combining valve to the key switch and then to the dash cluster to the warning light, which you said you don't have. So may be you don't need that wire.

The small wires on the diagrams I posted above with the fuses are for the battery gauge which you are not using because you have a voltmeter.

[The Rocknrod]

Just the two brown ones on the right next to the green ones.

[VetteVet]

Yes that's them, They are actually one wire from the master cylinder combining valve to the key switch and then to the light in the dash cluster.

You wouldn't have the green wires either if you had a temperature gauge and no temp warning light.

This applies to the 67 and later trucks but I thought the earlier models had a warning light. I'll have to look at the wiring diagrams.

[The Rocknrod]

Originally Posted by VetteVet

Yes that's them, They are actually one wire from the master cylinder combining valve to the key switch and then to the light in the dash cluster.

You wouldn't have the green wires either if you had a temperature gauge and no temp warning light.

This applies to the 67 and later trucks but I thought the earlier models had a warning light. I'll have to look at the wiring diagrams.

Thank you for the help.
I will pull out the gauge panel and check on the warning lights and wiring installed.