1990 T bird There is a short in the power window circuit and I need a schematic so I can try to find it.

Please do these check and let me know.

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit/System Description

The power window system will operate any time the ignition is the ACC or RUN position. The power window system will also operate whenever the body control module (BCM) is in retained accessory power (RAP) mode. The driver power window switch contains individual window switches for each of power windows. All windows may be controlled up and down from the driver power window switch. The individual passenger power window switches will only control the up and down operation of their respective power window.
Each power window contains a reversible power window motor. The direction the window travels is dependent upon the polarity of the supply voltage. By reversing polarity of the supply voltage the window motor will move up or down. Each power window motor is internally circuit breaker protected.
Battery voltage is supplied to the power window switch through the accessory voltage supply circuit. The power window switch also receives a constant ground source. The power window motor control circuits are connected to ground through the normally closed up and down contacts of the power window switch. When the power switch is placed in the down position, the power window motor down control circuit is switched to 12 volts and is applied to the down side of the power window motor. Since the other side of the power motor is connected to ground through the normally closed contacts of the up switch, the window travels down. By placing the power window switch in the up position, the polarity of the power window motor is reversed and the window travels up.

Reference Information

Schematic Reference Power Window Schematics
Connector End View Reference Power Door Systems Connector End Views
Description and Operation Power Windows Description and Operation
Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Circuit/System Verification

Ignition ON, command the appropriate door window UP and DOWN by pressing the appropriate Window switch. Observe the operation of the appropriate door window.

Circuit/System Testing

1. Ignition OFF, disconnect the B+ harness connector at the Driver Window Switch.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal D and ground.
?X If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal E and ground.
4. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. If the PWR WNDW fuse is open, test the circuit terminal C for a short to ground.
5. If all circuits test normal, test or replace the Driver Window Switch.
6. Ignition OFF, connect the harness connector at the Driver Window Switch.
7. Ignition OFF, disconnect the Passenger Window Switch.
8. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal and ground.
?X If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

9. Ignition OFF, test for less than 1.0 ohm of resistance between the control circuit terminal H and ground.
?X If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the Driver Window Switch

10. Ignition OFF, test for less than 1.0 ohm of resistance between the control circuit terminal D and ground.
?X If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the Driver Window switch

11. Connect a test lamp between control circuit terminal H and control circuit terminal D.
12. Ignition ON, command the passenger door window UP and DOWN by pressing the passenger window control on the Driver Window Switch. The test lamp should illuminate during either of the commands.
?X If the test lamp remains OFF, test for a short to ground or open/high resistance on either control circuit. If all circuits test normal, test or replace the Driver Window Switch.

13. Ignition OFF, reconnect the Passenger Window Switch.
14. Ignition OFF, disconnect the harness connector at the appropriate Window Motor.
15. Ignition OFF, test for less than 1.0 ohm of resistance between the control circuit terminal A and ground.
?X If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the appropriate window switch.

16. Ignition OFF, test for less than 1.0 ohm of resistance between the control circuit terminal B and ground.
?X If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the appropriate window switch.

17. Connect a test lamp between control circuit terminal A and control circuit terminal B.
18. Ignition ON, command the appropriate window UP and DOWN by pressing the appropriate Window Switch. The test lamp should turn ON when commanding the UP and DOWN states.
?X If the test lamp remains OFF during either of the commands, test for a short to ground on either control circuit. If all circuits test normal, test or replace the appropriate Window Switch

19. If all circuits test normal, test or replace the appropriate Window Motor.

Component Testing

Driver Window Switch
1. Ignition OFF, disconnect the harness connector at the Driver Window switch.
2. Test for infinite resistance between the signal terminals A and B and the B+ circuit terminal E with the passenger window switch in the INACTIVE position.
?X If less than infinite resistance, replace the Driver Window switch.

3. Test for less than 2 ohms of resistance between the signal terminal A and the B+ circuit terminal E with the passenger window switch in the UP position.
?X If greater than 2 ohms, replace the Driver Window switch.

4. Test for less than 2 ohms of resistance between the signal terminal B and the B+ circuit terminal E with the passenger window switch in the DOWN position.
?X If greater than 2 ohms, replace the Driver Window switch.

5. Test for infinite resistance between the signal terminals F and H and the B+ circuit terminal E with the driver window switch in the INACTIVE position.
?X If less than infinite resistance, replace the Driver Window switch.

6. Test for less than 2 ohms of resistance between the signal terminal F and the B+ circuit terminal E with the driver window switch in the UP position.
?X If greater than 2 ohms, replace the Driver Window switch.

7. Test for less than 2 ohms of resistance between the signal terminal H and the B+ circuit terminal E with the driver window switch in the DOWN position.
8. If greater than 2 ohms, replace the Driver Window switch

Passenger Window Switch
1. Ignition OFF, disconnect the harness connector at the Passenger Window switch.
2. Test for infinite resistance between the signal terminals G and F and the B+ circuit terminal with the switch in the INACTIVE position.
?X If less than infinite resistance, replace the appropriate passenger Window switch.

3. Test for less than 2 ohms of resistance between the signal terminal G and the B+ circuit terminal with the switch in the UP position.
?X If greater than 2 ohms, replace the appropriate passenger Window switch.

4. Test for less than 2 ohms of resistance between the signal terminal F and the B+ circuit terminal with the switch in the DOWN position.
?X If greater than 2 ohms, replace the appropriate passenger Window switch.
Window Motor
1. Install a 30-amp fused jumper wire between the control terminal A and 12 volts. Momentarily install a jumper wire between the control terminal B and ground. The appropriate Window Motor should perform the UP or DOWN function.
?X If the function does not perform as specified, replace the appropriate Window Motor.

2. Reverse the jumper wires; the appropriate Window Motor should perform the DOWN or UP function.
?X If the function does not perform as specified, replace the appropriate Window Motor

if the dimmer is ok and 12v to lamps the lamps are bad
pull them and replace them.
alldata.com has this.
the FSM for sure, (fact. serv. man)
no schematic ever needed. its just 12v , turn dim to full
see 12vdc there, if there, the lamp is bad.
if not there. the dimmer is bad, or the fuse to it is blown.
check fuses first.
the park circuit on all cars is the most complex (big) of all.
simple but goes all over car, inviting shorts. and blown fuses.
even trailer wiring hacks. ever look at your harnesses.
if just dash is dead.its in the dash.

Without any schematic diagram it sounds like the ECM has a short in it or something the ECM is connected to. Without a schematic for your particular car it is difficult to tell you the EXACT proble. Blown fuses means you are overloading the fused circuit. Just make sure the fuse is the correct size. Thats the best i can do with the Information i have
Good luck

I assume everything else works so start with the schematics and determine which fuse(s) and circuit(s) these power windows are on. Find the fuses. If these are OK, check wires for shorts, breaks and/or loose connections. If they are OK, check power window switches, then you'll probably have to deal with the window motors and connections.

Check the fan and fan clutch! Now that you have worked over the coolant circuit, make sure you have adequate air flow as well.

This type of power is typically for power seats and window type of circuits....Pull the fuse and see what quits working.

I had this problem before. Try replacing your driver's side power windows switch. They're cheap at a junkyard. This helped me out but during the process I tried shorting wires together to bypass the switch. I screwed up and all the power windows stopped rolling. This was remedied by sticking a pin into circuit breakers along the driver side wall under the dash. Hope that helps, was looking for help with my 90 Camry because it won't reverse and I can't push it backwards when in neutral. Good luck!

sounds like an ignition module

the ignition switch must be adjusted, it slides back and forth, did you check the adjustment? if not call me at home 925-459-0571

First check all fuses.
Check the switch on the door by making sure there is power to the switch and test the switch controls by back probing the wires and activating the switch. sometimes its trial and error.
If that is all good, then the window motor is at fault and needs replacing and the door panel has to come apart to replace motor.

If you think its a motor try pounding the lower end of the door while trying to roll window up with the switch. this may give the motor a second life but it may be short.