I'm looking for a good electrical schematic for the power windows on a 1988 GMC Sierra 2500 I have my Chiltons book however the schematics do not include the relays for power doors / windows

Google

year make model fuse box diagram

and

year make model tow package wiring schematic

Wiring, schematic, electrical diagrams,
fuse diag, error codes etc are basic contents of these online books they have here on this website www.reliable-store.com I have attached. Must check it out

Hi Steve,
Try search terms "GMC Sierra 1500 wiring diagram". This should yield a good few hits like: Schematic me Free Electronic Schematic Diagram and. http://fuel-saver.org/

Why not get the schematic and do the job correctly by scoping out what goes where?

Buy a Hayes Book or Chiltons for your model. Schematic drawings are in it. Hayes runs around $25 can be found or ordered at most local auto parts stores. I always buy one every time I purchase a new (to me) vehicle , sooner or later I've had to use it. Good Luck !

yes go to autozone they will read your vehicle free and show you exactly where the problem is to sell you the proper parts

You will need to ask the dealer parts dept this question, we have no way to reference this here at fixya.

The wiring diagrams for your 2003 GMC Sierra power window circuits are copyrighted material and cannot be posted here. However, I can describe the driver's power window circuit to you.

Battery voltage is provided to the driver's window (master) switch via the ORANGE wire at PIn #2 on the switch connector which comes from the 25 Amp Left Window Circuit breaker located in the fuse block on the left side of the dash.

There is a logic module located inside of the master switch which controls the "Auto Down" feature for the driver's window. When the switch is operated in either the "UP" or "DOWN" position, power and ground is supplied to the window lift motor via the BROWN wire (Pin #1, Connector 2) and the DARK BLUE wire (Pin #3, Connector 2) Thease wires will switch polarity dependin on whether the switch is commanding UP or DOWN.

The schematics show that the ground circuit for the driver's window motor is supplied internally by the driver's window switch module. It is most likely grounded inside the door panel itself - the schematics do not specify. To check for ground, you can test continuity to ground on BOTH the BROWN and the BLUE wires by back-probing them with the switch electrical connector plugged in and the window control switch in the NEUTRAL position. They should both have ground.

When the switch is operated, one will remain ground while the other switches to power.

This is for one with intermittant wipers.

it is all ecu controlled Marv