[Garrett Howard]

I am trying to troubleshoot an issue I'm having with the power windows in a 1998 convertible.
all windows have power except for the Driver quarter window. when the motor is unplugged, the reading is 11.97 volts. When the motor is plugged in, the reading won't go over .32 volts. I test at both the main switch and at the power plug, and get the same readings, 11.97 when unplugged, .32 when plugged in. I know for a fact that the motor for the driver quarter window works because when you plug it into any of the other power points for the windows, it turns with no issues. I can't find any area where there is a ground wire issue, or where there might be damage to the wires.

On inspection just a few minutes ago, I noticed that when the motor is plugged in, testing the down direction wire, when I press up on the switch (it is supposed to ground out) there is a .09 volt reading that comes, same if you test the up direction wire and press down on the switch.

any Ideas?

 

[wmburns]

IMO this is likely a perfect case study in WHY a volt-ohm meter (VOM) isn't the best way to test current carrying circuits. Best to also use a test light that will "load" a circuit.

Here's some more information about voltage drop testing. Hoping this will help add to your understanding WHY testing with a VOM may not give an accurate picture of a circuit's ability to carry a load (high resistance connection).

Howto perform charging system voltage drop test
https://www.stangnet.com/mustang-fo...perform-charging-system-voltage-drop-test.56/

If this were my car I would CONFIRM ground G300 from the black wire (pin #14) to carry current at the driver's door window controller. Then you will know before digging deeper into trouble shooting.

IF the ground is good then test the ability of the positive line LB/BK pin #15 to carry a current at the driver's door window controller.

Once we know for certain about the basic power, then more trouble shooting will be required.