Tailgate Relay Modification

[Fancy]

So after doing the relay modification for the power windows a long time back I would have to say that was hands down one of the my favorite modification a could have ever invested time and money into. They work 100x better and they remind me every time I hit that switch.

So I figure why couldn’t I do the same for the rear tailgate window? So I gave it a try… Now im not the greatest electrical wiz but I do know a bit. Got two more relays and wired them in as seen below. However when testing the window I will blow the 30 amp fuse for the 10 gauge power wire that runs to the relays.

As of the current way I have it setup that wire runs 25 feet in length so I am hoping that is the problem and it is just too much draw for the fuse. My plan is to shorten it to 10 feet or less with and end goal of 5-6 feet but im not ready for that yet.

However I was hoping to get some input from you guys who may have a little more electrical knowledge than me.

 

[Fordum]

Not sure what your problem is, but its not too long a wire. Too much wire would reduce the amount of current draw, so its not that. I can't spend a lot of time on it right this minute, but I should get to it tonight.
Without looking at it, I suspect it has something to do with the fact that the tailgate motor is different from the door window motors. I'll post back soon.

 

[Fordum]

OH, dude.......
Its real simple why the fuse is blowing. When the relay is off, the bottom contact where you have the 12v input, is tied to the center pin which you have tied to ground. Assuming that the 12v pin is no. 30 and the center pin is 87a.

Remember, in this case, unlike the door motors, you do not supply a ground. So, just cut off that wire tied to the center pin on both relays, and the system should work.

The door windows had two wires, which were both sides of the single motor winding. One had to be hooked to 12v, and the other hooked to ground. You hook it up one way and the motor goes up, reverse the wires and it goes down.
In this case, the motor has two windings. One for up and one for down. One end of each one is already tied to ground, so all you have to do is put power to which ever one you want to drive the window.
No ground switching required.

 

[Fancy]

HAHAHA so that exact thought had crossed my mind while doing the install however i was unsure about the details of either motor so i stuck to the plan assuming they were the same. Good news is you are correct. I can't even begin to explain my gratitude even though it is slightly embarrassing that i missed that. Just for the sake of others i will post up the new schematic tomorrow or soon so someone else may reference it.

Thanks Again

 

[Fancy]

So here is the Final Tailgate Wiring Schematic. Note the two center Terminals are infact left empty

 

[Mastiff]

Interesting. Two questions: how does it work now? and where did you put the relays, underhood or back by the gate someplace? The rear window does always seem like it's struggling.

 

[Fancy]

Actually Im surprised it hasn't been covered before, but i searched and asked awhile back and nobody seemed to have tried it. It works WAY better than before. My tailgate glass wouldn't even roll up without serious help if my truck was off. Now it will roll up in seconds (maybe 2-3). Again one of my favorite mods. I may even replace the motor and tracks later as well as grease the mechanical's as mine are in pretty poor condition. I took the opportunity to clean up the whole wiring harness in the tailgate and mounted the relays right there as seen below. It was the perfect spot. That way i only ran the 10 gauge power wire out of the tailgate which will be attached to my rear winch power (with fuse) once it is connected to the battery. In the mean time i ran it to the front. As you can see i haven't cleaned up and removed the two unused ground pins but you get the gist

 

[Mastiff]

Great idea. I'll add that to my list. Mine works, but it sounds pretty sad, especially when the truck is off. Lately it clunks once per move too, probably needs to be lubed.