2004 Power Window Switch Issue

[doug7740]

In reply #5 of this thread I told you to make sure that you check the condition of fuses 14 and 31. In reply #9 of this thread you said that fuses 14 and 31 were good and you went further and checked all the mini fuses as well and they were all good. Now you tell me that you realized that you had not tested the interior compartment fuse panel and you found that fuse 31 was blown. The advise I give you is based on the test results that you give me. Go back and read the entire thread and look at all the diagrams I have given you and I'm sure that you will figure this out.

doug7740
1955 Thunderbird Blue

 

[Miguel351]

When I was checking fuses, I was checking the fuses in the battery junction box as that's where the manual, and you, said to check. You then stated to check fuses 14 and 31 at the same time. I just assumed you meant 14 and 31 in that same battery junction box as there was no mention of the fuse box in the passenger foot well. So that's probably my fault for not realizing what you meant.

Either way, I did re-check all the mini-fuses in the fuse box by the battery AND in the passenger footwell. The only mini fuse that was bad was 31 in the passenger footwell.

 

[Miguel351]

Ok, another update today. Really starting to close in on what might be happening, I think/hope.

With power restored to the YEL/RED wire coming from the REM, I decided to jumper it to to driver's master control switch female connector, which is also the YEL/RED wire in order to bring the windows up and test both switches for their working condition outside of the static tests that I did on them separated from the harness. I was able to roll both windows up and down from the driver's master switch and the passenger side window from it's switch. In fact, with that wire jumpered directly from the REM, full normal operation of the windows was achieved. Furthermore, upon opening and closing the doors, the windows are back to performing their auto-seal feature as before. So, in summary, everything is back to normal, except that the switches still do not actually control the windows.

I did perform some other continuity and voltage tests on the YEL/RED power feed to the master control switch, too. For this, no jumper directly from the REM was connected, just all normal harness. Here's what I found:

-It is not shorted to ground.
-When the key is turned to the on position, a quick pulse voltage of up to .87 volts was seen on the DMM.
-When the connector is reattached to the switch, the key in the on position, and the driver's side window switch is operated, .38 volts is seen on the DMM, regardless of direction of the switch. When the passenger side switch is operated, .93 volts is seen regardless of direction.

The fact that fuse 31 in the interior compartment fuse panel was blown is intriguing to me. The manual says it's for the glove box and footwell lamps. The schematic posted earlier shows that the YEL/RED wire coming from the back of the driver's master switch ends up going out to "Interior Light System". I was working on it in a very well-sunlit area so I couldn't really tell if the footwell lights were coming on at all. Could it be that if the footwell lights are out, due to whatever the same reason might be that blew fuse 31, that it inadvertently causes the window switches to fail as well? Could it be like I mentioned before about multiple systems on one circuit and how if one item fails, it can adversely affect one of the others?

Do any of the test results above give anybody any ideas as to what the culprit might be?
Is there a secondary junction between the REM and the driver's master control switch connector that should be checked somewhere on the vehicle?

Thoughts? Suggestions?

 

[Miguel351]

The other day I replaced the interior footwell lights and now everything is back to normal, no burned out bulbs and no dead fuses(according to the last time I checked). Still, the window switches do not work. I think something else might be at play here. The FEM was replaced a couple years ago, so I decided to have a look at it and around it to see if there was anything that stood out to me or looked weird. Well, attached are some pictures that show something odd to me. There are some wires that are removed from their tape/sheathing and are routed around whatever that control cable is there. I've never known this to be something the factory has done or would do so it looks like some later technician did this.

Is it possible that the people who replaced the FEM did some other kind of jerry-rigging to either tap into power for something or to remove power from something?

Does the wiring in these pictures look normal to you who have seen this area before?

Should I test these wires for anything? If so, what are the conditions? Key on engine off, key on engine on, pushing certain buttons, etc.?

Well, since nobody is responding with their thoughts or suggestions as to what might be the heart of the issue here, is there anyone that can at least take a picture of that same spot on their car for me? It's the area just above the driver's side kick panel, right near the light where all the wires travel from under the door to up into the dash. I just want to be sure that what I see here is abnormal. If it is normal, and your car matches, I'm more than happy to continue my searching throughout the rest of the car's wiring/circuitry for the culprit. Either way, I just need some help here. Thanks in advance!

 

[doug7740]

doug7740
1955 Thunderbird Blue

 

[Miguel351]

Well, this was a fun little journey. Thanks for the pics, doug7740. I was able to contrast and compare with what was under her 'Bird's dash.

Found those two extra wires that were tapped into the main harness, followed them up to where they ended, and found a chunk of a unit there that was zip-tied to the main harness. It had all kinds of numbers and stuff on it(none of which were Ford part numbers) so I did some internet sleuthing and found that it was/is a LoJack system module. Definitely dealer installed, though. If this is affecting the power supplied to the window master switch circuit, I would assume simply unplugging it would remedy it. However, the wire it appears to be tapped into doesn't appear to be either the YEL/RED, or RED, or any of the 12V source wires involved in any of the wiring diagrams you provided earlier. In fact, it looks like it's tapped into a GRN/GRY wire. I've attached pics of what I found, including the wiring loom that was empty and left under the carpet. Weird.

I did, however, check any and all connectors in that area to make sure they were all firmly connected and all their wires were properly seated. I checked every connector attached to the FEM, every connector that went to/through the firewall, and every connector that was attached to that little block that hangs just behind the hood latch release lever. No change to the operation of the windows.

So, the situation remains the same: Both windows auto up/down sealing feature still works reliably. The 12V source power out from REM is good. No power to the driver's master window switch. Jumpered power from REM to master switch makes both windows work, from both switches. So, for some reason, that 12V power from the YEL/RED isn't making it to the master window switch. No DTCs present.

What am I missing? It seems like the solution should be fairly straightforward, but it eludes me, and apparently others here.

 

[doug7740]

Since I am not there and not the one working on your car, the advise I give you is based on the information you give me. Yes, the solution should be fairly straightforward. If the solution eludes you then the information you give me is not accurate information. You have been diagnosing this problem since September and you knew that the FEM was replaced, but you never even removed the trim panel until you saw the pictures I sent you. When you did remove the trim panel you discovered that there was a dealer installed LoJack system installed on the vehicle.

Don't just assume that by simply unplugging the LoJack module your power window switch issue would be resolved. Remove the LoJack module and its associated wiring harness, and return the wiring back to how it came from the factory.

doug7740
1955 Thunderbird Blue

 

[Miguel351]

Doug, I do appreciate the help you've given me over this time. I can assure you all the information I've given you is 100% accurate and true. One bit of information that a moderator trimmed from my very first post in this thread was that I'm no stranger to working on cars, and definitely not a shade-tree mechanic. I've done numerous engine and transmission rebuilds over the years and have also done plenty of electrical work, not only on cars, but on pinball machines of all ages. So when I've been sharing with you the information/results I've been getting, it's with the idea that said information/results should be a clue as to what's actually going on. I know full well that one circuit doesn't typically go down in a situation like this, it's usually a couple as things are usually daisy chained somehow. All of my findings and reports have been with the hope that something sticks out as "not normal" and indicative of what the actual issue might be. So far, every component I've tested has tested as working correctly and all fuses are now known working/good. So the mystery of what's happening remains since no other components or circuits' test results are abnormal, except for the power source wire to the driver's master window switch.

In one of my earlier posts, I mentioned that I can jumper directly from the REM 12V output to the source voltage input of the driver's master switch and properly operate both windows. However, when the switch is powered through the harness normally(sans jumper), upon operating the switch up, down, or auto down, only 0.8 volts is shown on the multimeter. That should be indicative of something. What, I don't know. I've never worked on a car that has so many different modules that overlap functionalities like this car does.

Furthermore, in one of your earlier posts where you mention to check fuses 14 and 31, you never mentioned in which fuse box location you were talking about. There are literally three fuse 14s and two fuse 31s. At the time, I was checking the fuses 20 and 28 in the trunk's fuse box, as directed. So naturally, I checked the 14 and 31 there and they were good. On a whim, I decided to check the interior panel's fuse box and that's where I found the 31 that was busted. I replaced it and the foot well lamps, and there was no change to the window control situation.

Also, for some reason, there are times where I log in here to post a response but the reply box stays full pink and I can't click on it to enter a reply at all. That's why there is large gap in between my posts, too. Since I only have time to log in a couple times a week, and if it's not letting me post, then I don't get to reply that day, or sometimes, week.

 

[doug7740]

The yellow/red wire at terminal #6 of the REM, that you jumpered directly to the master window switch, is the power source wire at the yellow/red wire of terminal #4 of the master window switch, terminal #3 at the yellow/violet wire of the passenger window switch and terminal #1 at the yellow/red wire of the antenna isolator module. It also is the power source for the illumination of both the driver and passenger door lock switches.









By bypassing the yellow/red wire at terminal #6 of the REM to terminal #4 of the master window switch you eliminated the yellow/red wire in the body main harness. There is a breakout to the Central Junction Box (interior panel fuse box) at that location. Is it possible that the LoJack module you discovered receives its power source at that location? Did you remove the LoJack module and its associated wiring harness and return the wiring back to how it came from the factory like I asked?

Remember, the FEM controls the driver’s window motor and the REM controls the passenger’s window motor. The master window control switch sends a voltage signal to the FEM for the operation of the left window motor and sends a voltage signal to the REM for the operation of the right window motor. The right window switch also sends a voltage signal to the REM for the operation of the right window motor. Did you ever connect a scan tool to the vehicle and check for fault codes in the FEM or the REM?

As far as the problems you are having posting to this website and the moderator editing what you are posting; you should private message the moderator and I’m sure he will help you resolve the issues you are having.

doug7740
1955 Thunderbird Blue

 

[fbodyman]

Miguel, was this issue ever resolved. Mine is very similar. I didn't discover a lojack. One thing in mine that is very perplexing is that< if you disconnect the battery or pull fuse 28 and reinstall. The window will work for one cycle. I do recall it working a few times once. when I turned key off and back on. nothing. Everyone says to have the REM rebuilt.​