2004 Power Window Switch Issue

[Miguel351]

The power window switches stopped working at some point. We live in Central California where summers get fairly hot so she rarely rolls them down in favor of just blasting the AC. But when she went trough the drive through with one of my nephews, the window wouldn't roll down. The reason why she never noticed it when it initially happened(whenever that might have been), is because the auto up/down sealing feature still works. Very strange.

When I first started diagnosing what was happening, that's what I saw: Power was still getting to the motors obviously, as they were doing their sealing dance, but the switches had no effect, regardless of key position or engine running. So, I took the master switch out and tested it for continuity and signal. I put my DMM on multiple pin combinations and got a change in resistance or signal for every switch action I performed, so I assumed the switch to be fully functional.

Then, I check voltages at the female connector that goes to the master switch. The ground checked out as good, and the power in(the YEL/RED, I believe on pin 4) shows nothing. I check it against the ground for a short, nothing, so it's not shorted out. I check it for resistance and it shows 1k ohms. Does that mean anything specific? Does a known working YEL/RED circuit produce the same result?

I've checked the fuses in the rear compartment and all check out good, specifically 20 and 28. The power door locks still work from the master switch and the key fobs. The passenger side window switch does not work. So, the problem is contained to window operation circuit only. Again, the window motors have power as they still do the auto seal function. I've check the REM to look for loose wires or connectors and found nothing. I have yet to disconnect and reconnect all the plugs going into it yet, as I know that's something Ford actually suggests. I've read up on some other threads looking for similar issues/solutions, but have yet to find something that mimics this particular situation. The closest one I've found so far, that also has some great circuit info that I used to hunt this particular circuit down is this one: https://forums.fordthunderbirdforum...window-issue-tbird-2002-still-searching.5985/ But again, it's close, just not the exact same issue. So this is why I'm posting here.

So, experts, what do I check next? Are there some specific fuses in the other panels to check? Is there a relay in the trunk fuse panel that needs to be tested? I am completely open to ANY and ALL suggestions. I'm just about certain there's a simple fix to this, outside of the REM being bad on just that one specific circuit. The first thing she had to do when she got the Bird was to replace the FEM, I'd hate to have to replace or rebuild the REM, too, but I know that's most likely going to happen eventually anyway.

I await your expertise!
-Mike

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[Miguel351]

Small update:

Did some further testing according to some of the Pinpoint tests found in a post from another thread and found that the voltages check out across the master switch connector(with the exception of the YEL/RED, of course). I also checked continuity on the YEL/RED wire from the connector to the master switch all the way back to the connector that goes into the REM, and it was good and not shorted to ground.

Is there a fuse or two somewhere for the FEM that controls that source voltage to the REM that then provides it to the window switches?

 

[biddle]

Small update:

Did some further testing according to some of the Pinpoint tests found in a post from another thread and found that the voltages check out across the master switch connector(with the exception of the YEL/RED, of course). I also checked continuity on the YEL/RED wire from the connector to the master switch all the way back to the connector that goes into the REM, and it was good and not shorted to ground.

Is there a fuse or two somewhere for the FEM that controls that source voltage to the REM that then provides it to the window switches?

You keep saying "Switches" however, when reading your post it appears the problem may be isolated to the passenger's side window. Is this the case?

 

[KBB_of_TMC]

You keep saying "Switches" however, when reading your post it appears the problem may be isolated to the passenger's side window. Is this the case?

Here in Texas in my non-Thunderbird Ford, I had a similar problem that turned out to be ~200 fire ants jammed inside the door switch. I took it apart carefully, cleaned out all the dead ants, relubed & reassembled it and all was fine again. I sprayed the inside of the door panels with insecticide and haven't had it happen again. just FYI...

 

[doug7740]

If I understand correctly neither of your power windows are working with the window switches on either door, however the short drop driver and passenger window feature is working correctly. Let’s start by understanding how the system operates:

The driver window control switch sends a voltage signal to the passenger window control switch and through the switch to the REM. The REM applies power and ground to the appropriate passenger window motor circuits in order to operate the passenger window up or down.

When the passenger window control switch is pressed, a voltage signal is sent from the window control switch to the REM, which powers and grounds the appropriate passenger window motor circuits in order to operate the passenger window up or down.

You mentioned that you checked the fuses in the battery junction box in the luggage compartment near the battery, specifically fuses 20 and 28. Make sure that you also check the condition of fuses 14 and 31.

As far as the FEM and the REM control modules. The FEM receives inputs and delivers outputs to a majority of the electronically controlled features which reside primarily in the front of the vehicle, including the left power window. The REM receives inputs and delivers outputs to a majority of the electronically controlled features which reside primarily in the rear of the vehicle, including the right power window.

So before you start thinking that the problem is with the FEM or the REM, start by testing the driver window control switch and the passenger window control switch to determine if they are defective. Before testing, the switches must be disconnected. Follow the component testing procedure charts below.






If your tests determine that the window control switches are not defective, then the next step is to test the circuits from the driver window control switch to the passenger window control switch, the FEM, the REM and ground using the chart and wiring diagram below.

doug7740
1955 Thunderbird Blue

 

[Miguel351]

You keep saying "Switches" however, when reading your post it appears the problem may be isolated to the passenger's side window. Is this the case?

No. Neither window control switch operates their respective windows, or any windows for that matter.

So before you start thinking that the problem is with the FEM or the REM, start by testing the driver window control switch and the passenger window control switch to determine if they are defective. Before testing, the switches must be disconnected. Follow the component testing procedure charts below.

This is the one main component I haven't test yet. I've tested the master window adjust switch and it's female connector, however, since you say that the power runs from the REM through the passenger window adjust switch, it'd make sense that if it was defective, it would end up affecting the master control switch as well. I will also check fuses 14 and 31 in the battery junction box in the trunk.

Quick question: while I'm testing the driver's master window control switch for signals and voltages, does the passenger side need to be disconnected as well? I might as well try it as it's easy enough to get to, just thought I'd ask.

I'll report back with my findings.

 

[doug7740]

You are testing the driver's master window switch for continuity and not for signals or voltages. When you test the driver's master window switch for continuity the switch must be disconnected from the connector.

doug7740
1955 Thunderbird Blue

 

[Miguel351]

You are testing the driver's master window switch for continuity and not for signals or voltages. When you test the driver's master window switch for continuity the switch must be disconnected from the connector.

doug7740
1955 Thunderbird Blue

Correct. That was the first thing I did. I removed and tested the driver's master switch a couple weeks ago, but not the passenger's switch. When I checked the driver's master switch for continuities, every action I made with the switches had a result on the DMM. But now that you've provided me with what exact pins do what and when, I'll double check everything and add in the passenger switch, too.

That's why I was asking about the source voltage being directed through the passenger switch, effectively making the master control switch slave to the passenger.

Thanks for all this help, too. I appreciate it!

 

[Miguel351]

Ok. Did a bunch of testing according to those service manual pages you posted, Doug7740. Pulled out my DMM and set it to the basic audible continuity test.

Fuses 14 and 31 were good. I went further and checked all the mini fuses as well and they were all good, too.

Driver's master window control switch acted as expected according to the testing procedure you posted above(14540).

Passenger window control switch had an anomaly. Pins 5 and 6, when the switch is at rest, produces a tone, meaning the circuit is closed when it should be open, according to that chart(14529).

So, is that the culprit? I'm sure, either way, it's a good idea to replace that switch since it's exhibiting abnormal behavior. I know the motors have VPWR since they still perform their auto up/down dance when the doors are opened or shut. So I'm guessing it's the VREF signal that's not getting to them due to the faulty switch. And it looks like, from the schematic, that the passenger switch outs do complete a circuit with some of the pins of the driver's master control switch. So that makes sense to me.

 

[Miguel351]

Well, bought a new passenger side window control switch(SW7133) since I hadn't heard from anybody here and because it's only $20. Here's the weird part, the pinouts on the new switch tested the exact same way as the old one that was in the car: pins 5 and 6 when the switch is at rest is a closed circuit. That's opposite to what this attached manual page says it's supposed to be.

But with both the old switch and the new one testing identically, that either means the new switch is bad, too, or more likely, the old switch is actually good and the problem lies elsewhere.

So....what do I check next? What other fuses or relays? Did I buy the wrong switch? (I checked sources too numerous to count, most said it was right, but there were some that said it was wrong, somehow.)

Is there anything "weird circuit" related that might cause it? By that I mean like how on some cars, like BMW's of the 80's, if a taillight was out, the cruise control would stop working because those circuits were all actually on a total resistance based circuit. So when the loads on each item were changed due to one load being missing, you never knew what else might just stop working. You still see it today on some cars with how their turn signals blink at a really fast rate. Chances are a bulb is out somewhere. 😉

 

[doug7740]

The FEM receives power (hot at all times) from the rear battery junction box through circuit 30-AJ80 (red/orange). With the key on, the REM provides power to the driver window control switch through circuit 7-AJ7 (yellow/red) and to the passenger window control switch through circuit 7-AJ18 (yellow/violet). The FEM provides power to the driver window motor while the REM provides power to the passenger window motor. The FEM senses the driver window position using sensors in the window motor and the REM senses the passenger window position using sensors in the window motor.

If both windows are inoperative from the driver window control switch only and you are positive that driver window control switch is not defective, the only other causes are;

• Circuit 7-AJ7 (yellow/red) is open
• Circuit 31-AJ80A (black/orange) is open
• A defective REM

doug7740
1955 Thunderbird Blue

 

[Miguel351]

The FEM receives power (hot at all times) from the rear battery junction box through circuit 30-AJ80 (red/orange). With the key on, the REM provides power to the driver window control switch through circuit 7-AJ7 (yellow/red) and to the passenger window control switch through circuit 7-AJ18 (yellow/violet). The FEM provides power to the driver window motor while the REM provides power to the passenger window motor. The FEM senses the driver window position using sensors in the window motor and the REM senses the passenger window position using sensors in the window motor.

If both windows are inoperative from the driver window control switch only and you are positive that driver window control switch is not defective, the only other causes are;

• Circuit 7-AJ7 (yellow/red) is open
• Circuit 31-AJ80A (black/orange) is open
• A defective REM

doug7740
1955 Thunderbird Blue

View attachment 29556

View attachment 29557

That's just it. The window motors ARE getting power. This is confirmed by the fact that they still do their auto up/down procedure when either door is opened. For some reason, the switches aren't getting power. However, I have yet to check the voltage to the passenger side window control switch via the Yellow/Violet wire. I'll do that tomorrow for sure.

I've checked continuity from the REM to the driver's master window control switch(Yellow/Red) and it was good. I did not check voltage on it coming directly out of the REM as since continuity is good, whatever voltage that's in the line should be present at the driver master window control connector.

 

[doug7740]

If both switches are not getting power, I would suspect that the REM is defective. The REM provides power to the driver window control switch through circuit 7-AJ7 (yellow/red) and to the passenger window control switch through circuit 7-AJ18 (yellow/violet). Did you ever scan the FEM and the REM for fault codes? A diagnostic code will tell you where the problem is.

doug7740
1955 Thunderbird Blue

 

[Miguel351]

I did put a code reader on it, but I'm not sure that code reader could process anything other than powertrain codes. Either way, nothing came up on it. I'll try a different one tomorrow.

 

[doug7740]

You can't just use a generic code reader, you need a scan tool that can communicate with the FEM and the REM. I know that Biddle suggests using the BlueDriver Bluetooth Pro OBDII Scan Tool.

doug7740
1955 Thunderbird Blue

 

[Miguel351]

You can't just use a generic code reader, you need a scan tool that can communicate with the FEM and the REM. I know that Biddle suggests using the BlueDriver Bluetooth Pro OBDII Scan Tool.

doug7740
1955 Thunderbird Blue

Will the FIXD reader work? I've got a friend that has one that I know I can borrow.

 

[biddle]

Will the FIXD reader work? I've got a friend that has one that I know I can borrow.

Amazon has a deal starting on them in 6 hours.

 

[Miguel351]

Put the FIXD on it, zero codes. Have others confirmed that the FIXD sensor can read the FEM/REM for codes?

Checked voltage on the Yellow/Violet to the passenger window control switch, nothing.

So, summing up what I've found through all my tests:

-Both window motors have power as they still perform the auto up/down when the doors are opened or closed.
-No voltage is going to either side's window control switch.
-Driver's master window control switch performs as it should according to Ford's service manual page posted above.
-Passenger's window control switch does not perform as it should according to Ford's service manual page posted above. However, the new replacement switch performs identically to the original switch. So, original switch is assumed good and Ford manual is assumed to be incorrect/have a typo.
-There are no DTCs of any kind, including anything related to the REM or FEM.
-Yellow/Red wire from REM to driver's master window control switch is not shorted to ground.
-Fuses in battery junction panel all appear to be good, including 14, 20, 28, and 31.

I think that's everything. If I missed/forgot about something, I'm sure it's listed in one of my previous posts.

Thoughts?

 

[doug7740]

Since you have no voltage going to either side window control switch and you said that you checked continuity from the REM to the driver's master window control switch (Yellow/Red) and it was good, it appears that you have a defective REM. Before condemning the REM, with the key on, check for voltage at pin #6 (Yellow/Red) of the REM. Remember, with the key on, the REM provides power to the driver window control switch (Yellow/Red) and to the passenger window control switch (Yellow/Violet).

doug7740
1955 Thunderbird Blue

 

[Miguel351]

Ok, interesting update today:

I realized I had not tested the interior compartment fuse panel, so I did that today. Found that fuse 31 was blown. Replaced it, and now I have battery voltage at the YEL/RED coming out of the REM.

Here's where it gets interesting. At some point over the past few weeks, the battery died from leaving the parking lights on after the first tests to see if there was electrical drain on the system when the window switches were pressed. Once the battery was recharged to full, the windows would do their quick drop, but not roll back up. I assumed this was due to the computer being reset and the windows not knowing where they were, necessitating their reset. But because the switches weren't working, the reset procedure wasn't possible. So, with all the door opening and closing over the past few times I've been there to test out other systems, the windows are all the way down. When I open the driver door, I can hear the relays firing to make the window do the auto up/down feature, but of course, the windows don't move since they're already down.

Now that the fuse has been replaced and there is voltage on the YEL/RED coming from the REM, you'd expect the windows to come to life. Well, they haven't. I suppose this is due to their full down position, but I'm not sure. I guess I need to check voltage at the driver's master switch before all else. If there's voltage there at the YEL/RED input, then what?

Do I need to jumper the wire in the connector(if there's voltage there) to get the windows to roll up a bit first, then do the window reset function? Or do I run a wire directly from the battery(or other 12V source) to the motor wires/connector to get it to run the window up?

TL😀R- Fuse 31 in the passenger compartment was bad and replaced, battery voltage is now present at the YEL/RED coming from the REM, the windows are both fully down, and the switches still don't work. Suggestions?