Rear Power Glass Inoperable K5/Suburban Tailgate

[heffalump]

OK so.. the rear glass in my blazer hasn't worked since I bought it .. the switch in the dash is gone and it appears the plug is too. I looked at the diagrams here but was hoping someone might have a simplified one just for the rear window.. since the plug is gone can I (easily) re-wire it with a different switch? Wiring is not my strong point so any help or suggestions would be greatly appreciated...

 

[89Suburban]

1987 K5/Suburban Power Tailgate Window Wiring Diagram

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windows automatic screenshot

 

[heffalump]

Thanks

 

[89Suburban]

Your welcome, good luck!

 

[HotRodPC]

Broke this off into a separate thread. I think this'll come in handy in the future.

 

[89Suburban]

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[ucs75]

Adding a wiring diagram.
For reverse polarity motors, you would ground 87a on both relays.
For self-grounded motor, 87a to ground would result in a short-circuit.
Do not ground 87a for the rear tailgate glass. It is grounded at the case.

I used red to represent thick guage driver wire, and blue for lower current relay-control.
(M) is the Motor

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[ucs75]

I'm going to enhance the design with a key-switch lockout when internal switch is in use. This is much cleaner to me, and makes a nice clean pack up front and in the tailgate.

The following 5 Diagrams should fully illustrate the setup.

For the Diodes, I will be using a Hella 9-Pin Diode module. It's about the size of a relay.

https://www.delcity.net/store/relays-power-distribution/specialty-relays/custom-diode-module/

This makes a very nice clean pack under the dash with only four wires required to complete the setup to the tailgate.
One high current positive
One switched logic current positive
One switched logic current negative
One logic level positive for rear switch (locked out by front relay)

1. All switches in neutral
2. Front Switch UP
3. Front Switch Down
4. Rear Switch Up
5. Rear Switch Down

Note* I had to use two simple motors in circuitJs to illustrate the concept of the suburban's rear motor. There was not a direct matching component for me to insert. Functionally is the same for the flowchart - but an explanation is warranted. The two motors represent the single rear window motor + for Up, + for Down, and Central Ground.

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