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That switch won't work with the original wiring. You'll need to use relays with it.

Looking at the wiring diagram. I understand the need to run 12 gauge wire to and from the relays on the load side, but why on the relay energize side? It takes very little load to energize a relay.

You don't.

I have read this forum for a long time and this is my first message.
I knew Serehill through all his intelligent messages, prepared and available, even if this is not the place for condolences, it struck me very sadly to know it past in heaven. May he be at peace.

I write in this post because I want to make this change to my tailgate of my '89 Waggy.
I read well and covered the schemes.
I do not want to pretend to make the option with remote control, I am content to have a reliable operation with the internal and rear switch in the tailgate.
I'm not very clear the pieces to buy from the list of dodgerammit: do not miss the rear switch of the tailgate? Which type to buy?

Thank you all, but first and most of all to Rick.

Super bummed to have lost Serehill - one of the nicest guys to work with.
Posted this elsewhere but wasn't sure if was the right spot

I installed my harness and never got around to actually plugging a window motor into it.

Finally installed my original window motor - it kinda worked slowly for 5-10 seconds then died.

I just assumed the OLD motor was had - couldn't ever get it to move again.

So, I bought a new/refurbished motor, installed it, powered it on, same thing... ran REALLY SLOW/weak (without the window installed, just on the arms) and within 5-10 seconds it died. I removed it from the bracket/arms/gears - plugged it in and tried to run it without any of that stuff - and the motor wouldn't respond at all.

I have a feeling something is wrong with the wiring and it's frying the electric motor.

Any suggestions/ideas??

Here's a photo of the harness/wiring installed without the motor:
I installed the two red wires in terminals 1 and 2 opposite of the blue wires - I'm 99% sure that's correct, but also wondering if that's where I went wrong?

Idunno but the two blue wires look smaller.

I'm wondering if they should go to the tailgatenotclosed switch.

Serehill seemed a pretty meticulous guy and I'm thinking he had the control signals on one terminal block and the output on the other.

I don't have the pins on the relay socket memorized so I'd have to dig out a relay to look at to know for sure.

No instructions came with it?

Edit:

After looking at a relay and that close up picher I think the blues go to relay pins 30 which would be the motor leads. Either the two on a two wire motor or the up and down on a three wire.

Gonna have to study the pics more. To try and understand what's going on with your motor.

Also, where does the safety switch connect? Maybe the connector in the red wire? Looks like it feeds the switches. Unmate it and connect to the switch in series if you have it; leave the connector mated as is if you don't?

Blue wires are up/down signal from relays. Looks correct to my untrained eye. I'd have to actually hold the harness and test it to know for sure.

Serehill got a couple leads crossed on my headlight relay. Was able to solve it over the phone. Very cool guy.

I should've thought of this before. Do you have a meter?

Hook it up to the two motor leads on the terminal strip and see what you get. Should be 12V in one direction and -12V in the other.

It's not unheard of to get a bad rebuilt motor.

here's pics of the motor - is there anything I can do with a meter to check the motor vs the wiring?

Ground motor body and apply 12v+ to ONE terminal.
Motor should spin.
Apply 12v+ to other terminal and motor should spin opposite direction.

Do NOT apply ground to either terminal while testing.
The early motor grounds via the case.

babywag wrote:
Do NOT apply ground to either terminal while testing.
The early motor grounds via the case.

This could be his problem. Doesn't the relay setup allow ground flow to opposite terminal?

SJTD wrote:I should've thought of this before. Do you have a meter?

Hook it up to the two motor leads on the terminal strip and see what you get. Should be 12V in one direction and -12V in the other.

It's not unheard of to get a bad rebuilt motor.

Ok... hooked up my meter to the terminal strip to the two wires I have running to the motor (this is my second time ever "experimenting with the meter" so not sure if I did things right) but... I did NOT get 12v and -12v - I got like .3400 or something and less flipping the switch either direction. - never got a "-" "negative" reading.

Bad ground? - pretty sure my ground is solid, but I'll double check.

What else should I try/check?

SJTD wrote: No instructions came with it?

Sadly... no instructions

SJTD wrote: Also, where does the safety switch connect? Maybe the connector in the red wire? Looks like it feeds the switches. Unmate it and connect to the switch in series if you have it; leave the connector mated as is if you don't?

I've currently deleted the safety switch - my understanding is that those are the two red wires plugged into each other that bridge from one board to the other board.

Possible that's wrong? (my understanding of Serehill's instructions from previous posts was to leave them plugged into each other to skip the safety switch)

babywag wrote:Ground motor body and apply 12v+ to ONE terminal.
Motor should spin.
Apply 12v+ to other terminal and motor should spin opposite direction.

Do NOT apply ground to either terminal while testing.
The early motor grounds via the case.

I know nothing about electrical, but I'm assuming you are suggesting just grabbing a wire that is not associated with the harness here and using that as the 12v+ source?

Also, could the problem be a lack of ground or lack of good ground in the tailgate? I think there's a ground through the wiring harness, but I wonder if I need to better ground the motor?

dodgerammit wrote:

babywag wrote:
Do NOT apply ground to either terminal while testing.
The early motor grounds via the case.

This could be his problem. Doesn't the relay setup allow ground flow to opposite terminal?

I know so little (NOTHING) about electrical - what would be the problem I would need to solve here and how would I test for it?

If the original early motors ground through the case, the relay setup could be causing the problem by allowing the terminal not receiving the 12v signal to ground. I'd test like baby wag stated. 12v to one terminal and ground the case. If it works, the relay setup is the culprit. Nothing wrong with the system, just won't allow your motor to function correctly. May have to go with newer style motor that is reverse polarity.

turtlehead wrote:
I know so little (NOTHING) about electrical - what would be the problem I would need to solve here and how would I test for it?

I am not a motor expert but I am struggling with how a DC motor could be wired so that it can be reversed using positive at one or the other terminals and ground for the negative. The electrical flow goes through the same path. The only way I can see this working is if the motor itself had a switch that changed where the ground connects in the circuit. If it only has to rotate in a single direction then a single positive terminal and body ground would work.


For Turtle:

A bit of background on how a DC (direct current) motor operates. But first a bit about DC. In a DC system the power flows from the positive side to the negative side. The negative side is often referred to as 'ground' in our Jeeps. For the most part, almost all cars have a negative ground but there are cars that have a positive ground. So the negative connection from your battery is attached to the body and engine. If you took a test lamp and connected one side to the positive of the battery and the other side to a metal part of the body or engine the test lamp would light. You would get the same result if you simply connected the lamp to the positive and negative posts on the battery. (You said you know NOTHING). If your car was made out of plastic or some other non-conductive material then it would need to have both a positive and negative wire run for every circuit. By using the metal body as ground there is no need to run a wire all the way back to the battery for the negative side of the circuit.

DC motors can operate in either direction. Normally this is rotation. The direction they rotate will depend on the flow of the electricity.
Most DC motors use the two terminals to 'reverse' the polarity. To rotate one direction the positive flow goes in one terminal, through the motor and out the terminal that is negative. To run in the opposite direction the positive goes into the other terminal, through the motor and out the terminal that is now negative. Because the positive/negative paths are switched the negative side is not connected directly to ground, there is always a switching mechanism in place. This is what Serehill's relays do, they switch which terminal on the motor is getting positive and negative when in operation.

Some DC motors only need to run in one direction, an electric fuel pump for example, is made to operate in one direction. Positive to one terminal and negative to the other (or ground). An attempt to reverse the positive and negative on such a motor will get mixed results. In some cases it might not work if it is protected with a diode. In other cases the gearing the motor is attached to might not rotate in the other direction.

will e wrote:

turtlehead wrote:
I know so little (NOTHING) about electrical - what would be the problem I would need to solve here and how would I test for it?

I am not a motor expert but I am struggling with how a DC motor could be wired so that it can be reversed using positive at one or the other terminals and ground for the negative. The electrical flow goes through the same path. The only way I can see this working is if the motor itself had a switch that changed where the ground connects in the circuit. If it only has to rotate in a single direction then a single positive terminal and body ground would work.

Reverse polarity motors like window motors flip voltage direction via switch input. Same for the rear motor. Mine (84) reverses based off of 12v direction through terminals. I don't know if early motors are different or not.

dodgerammit wrote:

will e wrote:

turtlehead wrote:
I know so little (NOTHING) about electrical - what would be the problem I would need to solve here and how would I test for it?

I am not a motor expert but I am struggling with how a DC motor could be wired so that it can be reversed using positive at one or the other terminals and ground for the negative. The electrical flow goes through the same path. The only way I can see this working is if the motor itself had a switch that changed where the ground connects in the circuit. If it only has to rotate in a single direction then a single positive terminal and body ground would work.

Reverse polarity motors like window motors flip voltage direction via switch input. Same for the rear motor. Mine (84) reverses based off of 12v direction through terminals. I don't know if early motors are different or not.

I think we are saying the same thing.

Looking at the relay pic in the first OP. At rest both relays connect negative to the two input terminals on the motor (Normally closed). When a relay is triggered it moves off of the negative input and onto positive, sending positive to one terminal then through the motor and using the negative path in the other relay. If the other relay is triggered it does the same but switches its negative to positive and sends the power to the motor then to the other relay.

will e wrote:

dodgerammit wrote:

will e wrote:
I am not a motor expert but I am struggling with how a DC motor could be wired so that it can be reversed using positive at one or the other terminals and ground for the negative. The electrical flow goes through the same path. The only way I can see this working is if the motor itself had a switch that changed where the ground connects in the circuit. If it only has to rotate in a single direction then a single positive terminal and body ground would work.

Reverse polarity motors like window motors flip voltage direction via switch input. Same for the rear motor. Mine (84) reverses based off of 12v direction through terminals. I don't know if early motors are different or not.

I think we are saying the same thing.

Looking at the relay pic in the first OP. At rest both relays connect negative to the two input terminals on the motor (Normally closed). When a relay is triggered it moves off of the negative input and onto positive, sending positive to one terminal then through the motor and using the negative path in the other relay. If the other relay is triggered it does the same but switches its negative to positive and sends the power to the motor then to the other relay.

Yep.

I think the $64 question for turtlehead is this:

Do the older window motors ground through the case? If so, this may be his problem.

Edit: I went to Tom Collins' page and couldn't find a schematic for a 72, but the 73 does show the case grounded. My 84, simply shows the motor and the two power leads. No grounds. If this is so, then he would need a more modern motor to work with the relay system, correct?