'88 Tailgate Window

[harleydeen98258]

Sorry for this, as I have been reading previous post on the subject, but I haven't been able find anything about a couple of wires that I have.

While troubleshooting my tailgate window today I came across a section of 2 ea wires, about a 1.5 ft. long mounted in the bottom center of the tailgate. One wire is solid red and the other is solid yellow. They have a pigtail connector on one end and the other end has been cut. So far I haven't found where these 2 wires are suppose to go let alone what they are for.

The only problem now is I got the window to go down using the key switch and can't get it to go back up. I don't know if these 2 cut wires have anything to do with the operation of the window or not. Anyone know what those 2 wires are for, or if they are even suppose to be there? Any help is much appreciated.

Thanks,

 

[Justshootme84]

Taken from memory of when I gutted the 88 tailgate, there are 6 wires going to the tailgate, 3 to the key switch then 3 to the glass motor. IF the glass is down, it is easier to trace whatever wires you have with the tg open. If you have a meter to test the current of each wire, you can check if the problem is at the key switch or from the dash switch. You can also jumper the motor wires between the key switch and motor to a 12V battery to get the window up.

The window will not go up if the tg latches are not fully closed. Sometimes re-shutting the tg with more emphasis will defeat this seafety feature if your latches are worn. You can also manually close the tg latches with the tg open. Just be careful to support the glass if it starts to roll up/out.

I'll see if i can find a pic of the tg harness at my SFO site, JSM84

Yeah, looks like a red and yellow wire run to the glass motor.

 

[Seabronc]

I believe the solid red and solid yellow are for the defroster grid.

If the window will go down but not up, the most likely failure is circuit 404 which is the Purple with light green stripe wire. In some years the circuit function is reversed and so the failing circuit would be 405 which is the Purple with light blue stripe.

You can temporarily put the window back up by reversing the leads to the motor with a set of jumpers.

Does the window operate from the driver switch? If not the failure could be right there since the path for ground via either switch is thru it.

Good luck,

>-

 

[Justshootme84]

Thanks for adding your input, SeaBronc. There is a purple wire or two in that key switch, and I'm not sure where all of them go. The 88 Custom I have does not have rear defrost, so it may differ from one with that feature.

 

[harleydeen98258]

Thanks for adding your input, SeaBronc. There is a purple wire or two in that key switch, and I'm not sure where all of them go. The 88 Custom I have does not have rear defrost, so it may differ from one with that feature.

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thanks...I got the window to go down using the key switch, but only after I connected to the yel/red and red/yel pair of wires. As soon as I come across some really long wire I'm going to try the jumper tactic...

 

[Seabronc]

thanks...I got the window to go down using the key switch, but only after I connected to the yel/red and red/yel pair of wires.

 

[CraZAg]

I just went through a similar problem with my '88. To get the window in a position to where you can trace all of the wire easily, you can take 12V positive and negative from your battery or some other source to the yellow and red wires you talked about. Touching the red to positive and yellow to negative will take the window one direction and swapping the wires will take it the other direction.

Instead of trying to figure out what was wrong between the key switch and the wiring, I decided to just run a new circuit with a switch in the front. The window switch will have 5 pins/wires on it. You will use the yellow and red wire, 2 seperate ground wires, and a positive 12V. You will need to get a meter out to check the switch you use. They are all set up a little bit different. This is somewhat cheesy, but is the easiest way to get a functional rear window in my opinion. If it was up to me, I'd put a hand crank on all of the windows.

 

[harleydeen98258]

Well I took some pictures so y'all can see what I'm trying to put into words. I figure pics can probably do a better job.

Pic #1 This is the pigtail coming off of the window motor and connected to the harness in the tailgate. This is how I got the window down.

Pic#2 This is the set of wires that I can't figure out what or where the are suppose to be doing. One end was cut and the other has a pigtail.

Pic #3,4,5 Are the mess of crap that the previous owner decided to do on his or her own. I'm thinking that I am going to clean up these connections with new wire splices and then some heat sink.

 

[Justshootme84]

HD, the cut wires may be from the previous glass for the defroster like SB stated. If they are not connected to anything and your glass motor works.

 

[Seabronc]

I agree with Justshootme84, if the wires are not connected to anything just pull them out.

Looking at pictures 3, 4 &* 5 I'd suspect that one of those connections is the reason for the tail gate switch not working. The Black/White is the power from the fuse (Fuse 12) to power the switch, (connection is working because you can move the motot down from the switch). The purple / light blue and the Purple / light green are the ones that take the ground side back thru the driver switch, One of those paths is bad and one is good). In your truck, I am guessing it to be the Purple / light blue.

If you have a meter, you can do a continuity test. Probe the purple with light blue on the side of the splice closest to the tail gate with the other lead connected to a good ground, preferably the battery (-). You should get a connection, if you do then probe the other wire, both should get a connection to battery (-). The one that doesn't is your failing return path for UP. If you get good continuity on both, then your failure is in the tail gate. If it is in the tail gate, you will need to get the window up so you can do the same checks at the tain gate switch. Possible failure points, the tail gate switch (low possibility), one of the splices (good possibility), Connector C418 (located under the left hand side of the vehicle, near rear lamp assembly( good possibility due to exposure to corrosion), C205 (located left hand rear of engine compartment (low possibility), C274 ( the connector on the driver switch (could be loose), the driver switch (could be bad).

Note, I left out the tail gate latch switch, since it has to be working in order to get the motor to move the window Down. However, with the tail gate open, you need to cheat the switch in order to get the motor to move in any direction.

Hope that helps,

>-

 

[harleydeen98258]

Hope that helps,

Ooooohhhhh yeah that helps alot. Now I just need to get my hands on a meter, but at least now I'm starting to understand these things. I not all that knowledgeable on electricty as I am with the mechanical side of things. It's just a learning curve.

Thanks folks,