4WD INDICATOR LIGHT

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echo7bravo

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I swapped the cab off my (86) K10 for a (79) C10 cab. Which by the way had to have the tunnel cut out and the high hump tunnel welded in. Anyways, I know that all the clusters pin out the same and my cluster has the 4X4 indicator light. What my question is.....

Does anyone know if I need to change any wiring to allow said indicator to work?

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echo7bravo

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@chengny I know you have the answer. I’m guessing the black and white wires from the transfer case complete the circuit. They seem to be tied to the power wire from the transfer shift illumination. But can I route the circuit through my 2wd cab wiring harness?

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It grounds on the drivers side right on the very top of the kick panel.
 

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But is there wiring in 2wd harness leading to the indicator light in the instrument panel?
 

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Anybody???
 

echo7bravo

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I can’t answer your question, but what I can do is assist in making it a stand alone part of your harness
Do speak. Because at this point I have a blank drawing board. Here is what I know.

There is an indicator light on the instrument panel that is wired by position 5 or 13 (can't remember at the moment)

I also know that there were three wires (2-black and 1- white) that tied in the harness pictured above on the transfer case and the illumination lamp on the transfer shifter.

That's it. I get the feeling that the positive wire (white) attaches to a harness somewhere and travels up to the indicator lamp. And that the other wire (black) is a ground that is grounded the same location as the illumination circuit of the transfer case shift illumination lamp. Then when the transfer case is engaged, it completes the circuit allowing the indicator lamp on the instrument panel to illuminate.

IF in fact I am correct.....I am assuming that there is no such wire in the harness for the 2wd cab. But, is there a way for me to create that circuit to the indicator lamp on the speedo?
 

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No, that can't be right. EDIT NOTE....I haven't sleep more than six hours over past three days.

Is there power in the printed circuit card to the indicator lamp in the cluster on the speedo and the transfer case switch completes the circuit to ground that lamp and turn it on?
 

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My guess is that the white is the bezel light for the selector. The black is ground that goes to and from the switch on the transfer case. I’m also guessing the cluster ribbon is hot on one site when the key is on. And needs the signal from the TC that’s how I would wire it anyway.
 

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Looking at the printed circuit, you can see where one side of the lamp is ground and connects to the black-150 circuit just as the other lamps do. The other side of the printed circuit card routes to the 4wd PIN (position 14). This lead must be the positive. But how to get power from transfer case to PIN 14?
 

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Looking at the printed circuit, you can see where one side of the lamp is ground and connects to the black-150 circuit just as the other lamps do. The other side of the printed circuit card routes to the 4wd PIN (position 14). This lead must be the positive. But how to get power from transfer case to PIN 14?
Is there a wire in that spot? You still have the 4x4 cab right. Practice pulling a terminal out of one of the other spots on the 4x4 plug. Then when you’ve mastered it remove the wire and harness you need from the 4x4 cab and incorporate it into the new cab.
 

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I believe my 4wd indicator lamp is under the speedo on the farthest left side spot. And it doesn’t have a wire going to it, it gets power from the printed circuit.
 

echo7bravo

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I believe my 4wd indicator lamp is under the speedo on the farthest left side spot. And it doesn’t have a wire going to it, it gets power from the printed circuit.
You are right. It does, however I am trying to figure out the wire that connects to the plug that is inserted into the circuit card. And how it ties into the transfer case and where it is routed.
 

echo7bravo

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Is there a wire in that spot? You still have the 4x4 cab right. Practice pulling a terminal out of one of the other spots on the 4x4 plug. Then when you’ve mastered it remove the wire and harness you need from the 4x4 cab and incorporate it into the new cab.
I think that is what I am going to do. Compare the two, trace the wire from position 14 and see where it is routed. And if there is not a wire in position 14 of my new cab harness....do as you said and insert one.

I'm still not sure on how the circuit is switch. It was late and I neglected to photograph or take note of it when I was disconnecting wires prior to removing the original cab. I just know that there is a switch with a white and black wire.
 

Honky Kong jr

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I think that is what I am going to do. Compare the two, trace the wire from position 14 and see where it is routed. And if there is not a wire in position 14 of my new cab harness....do as you said and insert one.

I'm still not sure on how the circuit is switch. It was late and I neglected to photograph or take note of it when I was disconnecting wires prior to removing the original cab. I just know that there is a switch with a white and black wire.
The switch is on the transfer case, I can take a pic tomorrow.
 
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