Power Window Issues 1991 Mustang Gt

[jnoles405]

I've been working on my power windows for some time now and I'm stumped. Here are the issues i am having. The driver window works as it should. The passenger window switch on the driver side will not roll the passenger side up or down. but i have power on the passenger side when the driver's control is pressed. The passenger side switch will roll the window up but not down. i have power to the motor when both the "up" and "down" side is hit. I have replaced the motor on the passenger side and it is new. i can hook it up to a battery and get it to turn both up and down. I also have researched for a possible relay but with no luck finding one.

Has anybody else had issues like this? Surely its not the new motor since the driver side control for the passenger side does not function. Also, i haven't found any broken wires and everything appears to have power like it should. I did get a wire diagram and still have not made any progress.

 

[mikestang63]

check the actual buttons on the switch- they tend to wear out. Also check that the switch- which is 2 pieces- has not separated and that when you push the button up and down that when you stick a 12V test light into the + connector on the bottom where teh + wire for that button goes, the light on the test light goes on.

 

[jrichker]

Diagrams courtesy of Tmoss & Stang&2birds

Power Window diagram 1987-1992

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring; http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

94-95 Mustang wiring diagrams
http://www.veryuseful.com/mustang/tech/engine/#95-95Diagrams

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

O2 sensor wiring harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangO2Harness.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pin out
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Mustang 5.0 Lights and Radio schematic, by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxLights-Radio_diag.gif

87-92 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang87-92 PowerWindowWiring.gif

93 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang93PowerWindows.gif

T5 Cutaway showing T5 internal parts
http://www.veryuseful.com/mustang/tech/engine/images/5_Speed_Cutaway_Illustrated.jpg

Visual comparison of the Ford Fuel Injectors, picture by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/Ford_Injector_Guide.jpg

Convertible top motor wiring http://www.veryuseful.com/mustang/tech/engine/images/mustang88VertTopMotorCkt.gif

Engine mounted fuel injector harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangEngineHarness.gif tang/tech/engine/images/mustang88VertTopMotorCkt.gif

 

[jnoles405]

check the actual buttons on the switch- they tend to wear out. Also check that the switch- which is 2 pieces- has not separated and that when you push the button up and down that when you stick a 12V test light into the + connector on the bottom where teh + wire for that button goes, the light on the test light goes on.

It does light up with my test light. I went ahead and replaced the switches at the beginning of this adventure. No change. When using a test light on the pigtail to the motor i get one side (red/yellow) that lights up when i press the switch up and down. The other only lights up when i press down. driver side passenger switch does the same thing

 

[jnoles405]

i use this same diagram. thanks for the post though!

 

[rogerblose]

I had a similar issue with my 1988 power mirrors where the driver mirror would only go up / down but not left / right. I replace the switch with no luck. I ended up figuring out that a power wire must have been broken going through the door to body bellows. Anyway, I made a jumper wire going through the bellows and 2 - 3M snap connectors at each end to jump the trouble area and all is good. I spent about 4 hours doing the trial and error to find the fault. My door must have gone through thousands of cycles over 28 years. Good luck.