Hi all, I need help with instruction on how to bypass the GEM which is controlling the "Auto down" function of the driver side power window.

My driver side window works intermittently. It will work normally some days and other days will not work at all.
The switch is ok, the motor is ok.

Reading another threat, one of the poster had a diagram with instruction on how to bypass the GEM. The result would be losing the "auto down" function of the window but at least you are able to move the window up and down normally again.
It's an old post and the diagram and instruction has been removed by the poster.
Here is the link:
https://www.f150online.com/forums/el...y-98-f150.html

If anyone could help with instructions on how to bypass the GEM will be appreciated.
Or if someone could indicate were the GEM is located on a 1999 F150, maybe by cleaning the contacts will help.

Thanks in advance.

 

Taking a look at the power window diagrams, it seems that it is as easy as wiring the down side of the switch to the motor ( so it looks and works like the passenger side ).

Diagrams :




diagram 100-1 triangle A is wired to the GEM. Cut this wire ( in the door ) and wire it direct to the switch at triangle D shown on 100-2.

This will have the down side of the motor direct to the down side of the switch.

Curious how you ruled out the switch or the motor being an issue.

 

Thank you SSCULLY
Will do the modification tomorrow and post the result.
I have this problem for more then a year and did all the troubleshooting suggested and came to the conclusion that the only thing left is the GEM bypass.

Below a picture and comments received today from a member here at the forums:

"Hi, I was able to find the attached picture of how to do the GEM bypass and using the picture I tried it on my truck and it worked perfectly! It was so easy - just cut the brown power wire in the wire harness, cut the orange wire to the window motor and splice them together. Then cap off the two wire ends. I then taped everything back up and put the door back together. I also replaced the power door lock actuator while I had the door apart. Now the window and lock work great all for $25.00."

( UNABLE TO ATTACH PIC )

 

I found out the hard way that the motor is bad.

After the mod no joy.

Then tested the motor with a power supply still connected to the window and nothing.

However without load on the motor(motor removed from the window) it runs ok.

Just ordered my third motor, this time a motorcraft, no aftermarket, done with that.

Conclusion: Test your motor while still hooked to the window.
All previous test done before this was done with the motor removed and it would work normally.

Must be some electronic inside the motor working intermittently that causes the motor to work properly now and then.

 

That is why I asked "Curious how you ruled out the switch or the motor being an issue."

For the next member that has this issue ( Biro you already figured this out the hard way ) disconnect the power window motor at the pigtail ( there is a 2 pin connector in the door about 6" to 8" from the motor ) and hook a digital voltage meter to the harness towards the switch.

Press the power window switch to the up position, the meter will show a value of VDC
- Depending on which way the meter is hooked up, the first reading might be - VDC or + VDC

Press the power window switch to the down position, you should get the opposite polarity reading of the 1st value.
- e.g. If the switch up position was + 12.8 VDC, the down should be - 12.8 VDC.

If the voltage values show correct at the plug for the pigtail, the switch and GEM are not an immediate issue and further testing needs to be done.

I post not an immediate issue, as it could be an AMP issue.
If the OTD relay in the GEM is not supporting the AMP load required to operate the window, that could be an issue with the OTD relay or the power window motor.
- It would take further diagnoses at that step, if one gets that far, but I would take a guess and say that is going to be 2% of the cases, not a common item.

 

Hi SScully and Biro, I have been following your postings and your knowledge of your power window problems. May I also ask for your help?
About a year ago my drivers side window started rolling itself down, sometimes all the way down, other times it would go and stop. I was usually able to roll it back up. Now it has quit completely, won't go either way. I can hear a "click" sound when I press the up button (window is up), but nothing when I press the down button. Last winter I swapped #4 and #5 relays and that seemed to help the problem, but only for a few minutes, and it would start again. Now it doesn't work at all. I have remove the door panel, disconnected the motor pigtail and connected a separate battery and can see the window work both up and down. Again, this is with a completely different battery setting on the floorboard using a couple jumper wires. Under a load I assume the motor is OK. I don't have a digital Ohm Meter (going to get one soon !), so I used the trusty old test light. Plugging the motor back into the truck power I can see that I have power coming out of the switch in "up" "down" and "auto down", when the switch is depressed. At the motor connection I have power in "up", I can also hear the clicking sound at this time, but when I depress the "down" buttons I have no power at all at the motor. If I roll the window down using the battery on the floorboard, the switch will roll the window back up. I do not want to start cutting the wiring harness all up, yet don't want to throw hundreds at this problem either. I have taken the switch apart and cleaned it (it looked fine), and didn't help at all.Would you gentlemen have any thoughts on this problem?

 

I think I got an email from you, if so check your email, I've attached the picture. (Unable to attach here in this post)

Just be careful with the wire colors SCULLY schematics gives the correct coloring.

In the picture the wire looks like BROWN but its not.
Its TAN with LIGHT BLUE stripe. (TN/LB)
That's the one SCULLY is referring as "D"
The other one "A" is ORANGE with WHITE stripe (OG/WH)

You will be cutting only 2 wire.
I did not solder anything back, but used SLIDE FEMALE and MALE connectors for 16 to 14 gauge wire. You can buy them at Wal-Mart or Radio Shack.

 

deniseinor,

Can you post some info on your truck or complete your profile.

not sure what MY and trim level you are talking about, to offer any suggestions.

 

Was not me, I did not get an email.

"attaching' pictures :
https://www.f150online.com/forums/qu...-pictures.html

 

First picture is my harness with notes.
The second picture was emailed to me from a member here.
Third picture is the type of connector used.

 

SScully, I have received the instructions from Biro, on how to bypass the "auto down" on my drivers side window, but haven't done it yet....My concern is that having read through a lot of posts online about the GEM malfunctioning and causing other problems ie: the passenger window, the 4wd circuit, the radio, domelight, etc.....this could be just the beginning. Hacking up the wiring harness would be a quick fix now, but whats next ? I have an F-150 XLT Extra Cab (has a rear door on passenger side) 4wd.
I have also read that is not as simple as buying a new one and replacing it,(1) Ford doesn't make them anymore, and (2) it would need to be tuned to match the truck.
What would my chances be of trying to remove and repair the current problem with my GEM ? Thanks for your help. If you need more info please let me know.

 

SScully, Sorry, forgot...it is a '97 F150 .

 

I am still thinking you have an issue with the motor itself.

It is very strange for the motor to roll itself down electrically, where if it went slack mechanically, is there enough for gravity to act on to let it roll down ?

Is it fairly common for it to do this ?
- If so I would leave the door panel off and unplug the motor before parking it for the night and see if it still rolls down. You might have to do this for some time to confirm if it is electrical or mechanical issue.
- the motors have a some what common occurrence of having issues with the brushes and not rolling up. You might have ID'd another symptom that others have not seen yet ( e.g. replaced the motor sooner than you have gone with the issue ).

Side Note :

The list you have is if the GEM is water soaked from a leaking windshield or if the moon roof drain tube came off. That is another list of items, that unless your issue coincides with heavy rain or washing the truck, I would not put a lot of "what if" time into it right now.

 

I pulled the fuse panel and got to the GEM yesterday. It showed no signs of water intrusion. Blew it out with compressed air, was only a little dusty. The window rolling down was an electrical short not a mechanical issue, it works great both ways when tested with a spare battery setting on the floorboard and jumper wires and the motor unplugged from the wiring harness. Tried to check continuity on all wires from the switch but that was virtually impossible without tearing all the wire harness apart. I have power at 2 wires on the switch the "gray" and the LTBLU/BLK stripe. Is this correct ? Should I only have power at 1 place on the switch ?

 

You should only have + VDC on the gray wire when you press the switch all the way to the OTD position ( full back, instead of part back ).

The light blue w/ black stripe wire will have + VDC any time the accessory delay relay is active ( key in accy or run position or after turning off truck for 10 min and before opening the door ).

Not sure that your test ruled out a mechanical issue with the window rolling down. Your test only confirmed normal operation of the window while applying power direct to the motor.

The test case you are after is with what should be no power applied, overnight the window lowers.
- That is not what you confirmed.