I have a 1999 F150 (4.6, not that it matters for this) Lariat and ever since i replaced the drivers window regulator and motor the auto down button doesn't work correctly. before the motor died everything, including the auto down window, worked fine. When I "double/Hard" press (not sure the word to use) the window switch to do auto down it'll go an inch or so then stop, press it again and it'll go another inch or so and stop again, If I "single/Soft" press the button it goes all the way down no hickups and up works fine too.

Main question is how does the auto down window work, does it go by resistance so I have to lube the track or something (If so where/What)? or is it something else? If anyone can offer any tips I can try when I get a chance I'd really appreciate it. I also bought a new window switch off ebay (Motocraft, not dorman or any others) and tested it didn't change, same issues, so I have a brand new switch for a backup now.

 

There is a "one touch down" relay in the fuse box, perhaps it's no good.

 

The feature works by the GEM module energizing the OTD relay which drives the motor in the "down" direction. Power to the motor is run through a current shunt, the voltage across which will be proportional to the current drawn by the motor. This voltage is monitored by circuitry in the GEM module that will, if the voltage across the shunt exceeds a preset limit, de-energize the OTD relay removing power from the motor.

Your replacement motor/regulator is probably drawing too much current (for whatever reason) and the OTD circuitry is interpreting that as a motor stall and turning off the drive power, just like it's supposed to do at the end of the window's regular travel.

Mechanical binding of the window would certainly cause this symptom. The OTD relay is unlikely to be a cause of the issue.

 

yeah, tried replacing the relay and that didn't fix it, I didn't think It would, but I tried. Is there any special "Grease" i should use for the window tracks? or just hose it down with some WD-40? or would it be something else?

 

Don't know if you had removed the rear channel guide to do your repairs but I had a drivers window that would slow up in the middle of travel. I removed the door panel and found the rear window guide channel was installed incorrectly which caused the binding. The top of the channel has a permanent clip that slides into the upper channel for alignment. It was miss-installed by someone as the door panel had signs of being removed before. To fix, with the window up, I unfastened the bottom bolt holding the rear channel in and re-positioned the top guide clip and refastened the bolt.

 

When necessary I use a spray can of silicone. Once it dries it doesn't have that greasy feel to it.

 

I’m having the exact same problem. I replaced my driver side window motor and regulator and now the auto down function doesn’t work properly. It travels a short distance and then stops several times. I’ve tried resetting by holding the button down 3 seconds but nothing changes. I replaced the relay and that did nothing. I’ve lubricated the tracks and the window is not binding. Did you ever figure out the fix to this issue?

 

In my experience the only replacement regulators that WILL work with auto down for 97-03 trucks are the Ford ones. All the aftermarket ones I’ve used caused the auto down to be inoperable.

Not the case on 04-08s though as I used to put Dorman in those because at the time they were a lifetime warranty part and the Ford part had yet to be revised. So at least when it failed again the part was free. They worked just fine with auto down.