Howdy y’all,
forgive me if this has been asked before but I skimmed through about 20 threads and couldn’t find my specific problem.

On my 2003 FX4 level II I have had a few problems with my windows, at first it was just the motor being burned out so with little difficulty I replaced it (with a dorman, ugh) and all was good until about two weeks later, the window stopped working again for no reason and so I thought the motor was shot again, maybe there was a short in my wiring causing motors to burn out. So just for shiggles I rigged the motor to a car battery to see what happened and lo and behold it works fine.

So now I check to see if I have any power to the switch and it has current running through it, the relay under the dash clicks when I press the driver side up button but still no movement in the window. The number 12 20 amp fuse under the hood is fine and I checked to see if there was power flowing directly to the motor but I couldn’t get a good connection to see.

Does anyone have any tips I could use to narrow down this problem further? Any input would be much appreciated and thank you for taking the time to look into this problem of mine.

 

Power windows are easy to test, but have to take door panel off

Windows motors are 2 wire DC motors, which means you reverse polarity to make them reverse direction
So 12v on one wire and ground on the other makes window go up
Reverse that, ground on one wire and 12v on the other and window goes down

So unplug the 2 wire connector for motor
Put Volt meter's 2 probes in the 2 wire connector that goes to the switch, set for DC Volts
Press the window button
Should see either 12v or -12v if switch is working, push other side of button and it should reverse, 12v would now be -12v and -12v would be 12v

If not then switch is bad, if both ways work then motor is bad, assuming it didn't work to begin with lol


I little more back ground
When a window switch is not being touched BOTH wires to the motor will be GROUNDs, you can test that with OHM meter
What the switch does is unground one wire and change it to 12v when you press one end
If one of the grounds is bad then window may only work in one direction

Master switch(drivers door) has ALL the grounds for ALL the windows, 2 or 4 windows doesn't matter
So passenger windows 2 ground wires come from Master(drivers side) switch, each door has its own 12volt wire though

So when you press drivers door passenger window switch it ungrounds one wire and sends 12v activating the passenger side window
Passenger side switch does the same, has both wires grounded already, ungrounds one and sends it 12v

If no windows work it could be the 12v fuse or a relay, BUT..............it could also be the ONE GROUND wire in driver side kick panel that grounds all the switches via the Master switch

Window motors have thermal Limiters inside, on one wire, when window gets to the top or bottom so stops moving, the current draw spikes, and the bi-metal limiter cuts the connection, works the same as turn signal flasher
Brushes on the motor can wear out and the limit switch can a well, so motor stops working