Suburban tailgate window goes down; but not up!

Hi; I just bought an '89 Suburban and am trying to get it on the road. It has a tailgate, and the window doesn't operate properly. I found some mechanical problems: the tracks are a little ratty (I'll replace them),
and the nylon wheels that run in the tracks are worn out (can they be replaced without replacing the whole assembly?). The window goes down with ease; I plugged in the power and put it down and it's still down! It wont't go up; doesn't even try. I assume the switch is supposed to just reverse polarity and the motor is supposed to run forwards or backwards. I tested the voltage at the plug which attaches to the motor; I get +5.8 volts when I put the switch in the down position; -0.38 volts in the up position; I was expecting -13V and +13V. I see a little switch at the right latch assembly; looks like something to do with not allowing one to operate the window with the gate open (or maybe not open the gate with the window closed???) In the morning, I'll disconnect the switch at the latch, and jump past it; then, next step, check the dash switch. Also, the keyed exterior switch is seized (maybe that's the problem??). Any suggestions? Thanks. Keith.
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Bingo. When the interlock switch goes bad it goes down but not up. You can replace the switch easily for less then $12 or you can just jump past it but you must make sure the tail gate is fully closed each time you put up the window. If the window is ever close when the tailgate isn't completely close the window can shatter.
good luck, mark
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Hi Mark; Yup, that fixed the motor problem; thanks. I just cut the wire and connected it back together, by-passing the switch. Changing the switch is now way down on the priority list (hope I get to it before I shatter the window!). Now, those little nylon wheels that run in the track need to be replaced. I hope someone has new ones....I'll check with GM on monday. Sure hope I don't have to get the whole assembly! Keith.
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I am not sure about the wheels but GM still carries all the parts for these trucks. A few years ago I completely rebuilt the tailgate (new slides, motor ect) and they had everything. You should get a catalog from LMC they have almost everything for the truck except a new frame and sub-body... Make sure you keep and eye on the rear wheel wells they rust extremely fast and are hard to fix. As a side note if you have a 91 like mine you have to tell the autoparts guy that it is a 90 or you will get parts from the new body style suburban. good luck
http://www.lmctruck.com/scripts/mgrqispi.dll?APPNAME=WebLmc&PRGNAME talogRequest&ARGUMENTS=-ATK,-ACSB
mark
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