Read the first few pages of Chapter 2 of the TM 9-2320-289-34 tech manual to learn how to read the wiring diagrams and how the wires are labeled for the diagrams
Lets trace the stock starting circuit:
1 - 24v comes off the 24v Positive terminal block via the red fusible link 1 RED-2Z
2 - A few inches after the terminal block the fusible link changes to a larger red wire 3 RED-2Y
3 - The red wire runs along the back of the engine in the wiring harness to the firewall terminal block
4 - At the terminal block it travels to inside wiring harness to the starter relay under the center of the dash
5 - There is a splice near the fuse box and the red wire 3 RED-2X supplies power to the bottom fuse in the fuse box. This fuse supplies power to the GEN2 exciter circuit and the 24v portion of the voltmeter
5a - The red wire continues on to the starter relay under the center of the dash
6 - When the relay is engaged 24v travels through the solid purple wire 3 PPL-6 back to the firewall terminal block
7 - The purple wire travels back to the engine wiring harness and on to the starter solenoid at the starter.
8 - When the key is in the start position power travels down the purple wire and energizes the starter, allowing the starter to crank
Now to the ignition switch. I will not show how the power gets to the switch. That is another lesson.
1 – When the key is in the start position, 12v is supplied to the yellow wire 3 Yel–5.
2 – On the early (1983) CUCVs the yellow wire goes to the Neutral Safety/Backup Light Switch on the bottom of the steering column
3 – On later models the Safety Switch position is no longer used. Why? Who knows
4 – The yellow wire splices into three purple/white wires.
3 PPL/WHT-930B Water-in-fuel circuit,
3 PPL/WHT-930C Glow Plug circuit
And the 3 PPL/WHT–930E Starter circuit
5 – The purple/white wire connects to the starter relay coil under the center of the dash
6 – The starter relay coil is connected to the harness ground circuit which connects to the 6 legged ground terminal block near the parking brake.
So as a recap:
1 - You turn the key to the start position
2 - The starter relay energizes
3 - When the relay energizes, the contacts closes and allow 24v to travel to the starter solenoid
4 - The Starter solenoid energizes and the starter engages
5 - When you move the key out of the start position, the relay disengages, the starter solenoid disengages and the starter stops
Lets trace the stock starting circuit:
1 - 24v comes off the 24v Positive terminal block via the red fusible link 1 RED-2Z
2 - A few inches after the terminal block the fusible link changes to a larger red wire 3 RED-2Y
3 - The red wire runs along the back of the engine in the wiring harness to the firewall terminal block
4 - At the terminal block it travels to inside wiring harness to the starter relay under the center of the dash
5 - There is a splice near the fuse box and the red wire 3 RED-2X supplies power to the bottom fuse in the fuse box. This fuse supplies power to the GEN2 exciter circuit and the 24v portion of the voltmeter
5a - The red wire continues on to the starter relay under the center of the dash
6 - When the relay is engaged 24v travels through the solid purple wire 3 PPL-6 back to the firewall terminal block
7 - The purple wire travels back to the engine wiring harness and on to the starter solenoid at the starter.
8 - When the key is in the start position power travels down the purple wire and energizes the starter, allowing the starter to crank
Now to the ignition switch. I will not show how the power gets to the switch. That is another lesson.
1 – When the key is in the start position, 12v is supplied to the yellow wire 3 Yel–5.
2 – On the early (1983) CUCVs the yellow wire goes to the Neutral Safety/Backup Light Switch on the bottom of the steering column
3 – On later models the Safety Switch position is no longer used. Why? Who knows
4 – The yellow wire splices into three purple/white wires.
3 PPL/WHT-930B Water-in-fuel circuit,
3 PPL/WHT-930C Glow Plug circuit
And the 3 PPL/WHT–930E Starter circuit
5 – The purple/white wire connects to the starter relay coil under the center of the dash
6 – The starter relay coil is connected to the harness ground circuit which connects to the 6 legged ground terminal block near the parking brake.
So as a recap:
1 - You turn the key to the start position
2 - The starter relay energizes
3 - When the relay energizes, the contacts closes and allow 24v to travel to the starter solenoid
4 - The Starter solenoid energizes and the starter engages
5 - When you move the key out of the start position, the relay disengages, the starter solenoid disengages and the starter stops
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