Power Window main switch assembly "repair"


This is a slightly edited post that I made to the alt.autos.isuzu internet newsgroup asking for help with a problem.  When I didn't get any, I gave it a shot myself.  I've edited it out to change it from my question post to an information article.


I seem to remember reading somewhere here about problems in the circa 1994 era troopers and the drivers power window switches assembly...  Looks like I've run into that problem as well and the dealer wants $206 for the part!  :-(  I'll lay out all the details I've found and made notes on.  Issue is that the driver's window will go down, but not back up.  All other windows work just fine!  First thing I'd advise anyone having problems is to disassemble and clean the contacts, mine were all blackened from arcing when the switches were flipped.
 
To start with, here's the wiring connections on the switches side of the connection as I've noted them.  Numbers are random, just the order in which I jotted them down.  First color is primary, 2nd color listed is the stripe color:
 
1.    Green/Red        Illumination lights when headlights are on
2.    Red/Green        Illumination lights when headlights are on
3.    Blue/Black        12V+
4.    Blue/White        To FL
5.    Blue/Blue          To FL
6.    Green/Yellow    To FR
7.    Red/Yellow       To FR
8.    Green/Black      To RL
9.    Red/Black         To RL
10.  Green/Blue        To RR
11.  Red/Blue           To RR
12.  Black/Black      Negative/Ground
 
Looking at the connector looks something like this:
 
                  5    4
8   2     3   9    10
7   6    12  1    11
 
Hopefully that looks OK and makes sense - that's where the pins from the wires listed above are located in the connector.
 
To disassemble the switch assembly, first pop off the button that disables the other window switches, then work your way step by step taking out the screws.  All the screws are the same, so you shouldn't have to worry about mixing them up.  After you take out the 4 screws to remove the top plastic part of the rocker switches from the rest of the assembly, take it off gently so you don't send all the little metal rockers flying.  At this point, you'll see what makes the switches switch.  If yours are blacked as mine were, it would probably be good to take off the little rockers one at a time and clean the underside where they have gotten blackened, as well as the contacts on the "board".  I used a paper towel and then a pencil eraser to get them good and clean.  For the drivers switch unit, I just gently bent the contacts and used a paper towel piece as best I could.
 
Basically the way all the switches (except the driver's window) work is this:  By default, for example, 6&7 are connected to the ground.  When you flip the switch one way or the other, it connects either 6 or 7 to 3 for 12v power to raise or lower the window, depending on the polarity.  This is basically the same for the driver's window, but there is some electronic circuitry and a solenoid to enable it to lock down for a short time to lower the window all the way with one push of the button.  The "lockout" button basically just removes the ground connection from the other 3 switches so as to keep them from working.
 
I then test the switches and all work properly (ohm-meter between ground or 12v+ connection) and they flip-flop and transfer current as expected.  The drivers window, in the up direction all looks perfect, but in the down direction, either the 12v+ or ground (can't remember which now, but I think +)  showed full current flow on one wire, and some flow but with resistance on the other.  I'm guessing this is due to the circuitry that allows it to go down with one click?  However, down works fine, it's the up I'm having problems with!  If I take my tester leads and punch them into the vehicle side of the connector on 3 and 12 (12v+ and ground) and the touch them in one direction or the other to 4/5 I can get the window to go up and down with no problems!  I'm stumped because it looks like it should be working!

(Notes here - FL=Front Left, FR=Front Right/passenger side, etc)

I thought about wiring a momentary switch into the up direction, but that wouldn't work because at rest, both wires (4&5) are shorted to ground, so if I put in a 12v+ into it, it would short to ground and blow a fuse.  Another thought was swapping 4/5 with 6/7 to get the FR switch to run the FL window, and you could still reach over and run the FR window with its own button on that door.  I can't seem to get it straight in my head if I'd break something by doing that though...  Will the FL weirdo switch work fine in line with the FR switch?  Will the FL switch on the drivers door properly take the place of the FL weirdo switch?  Logic says that would since I can short wires myself and get it to work...?  The odd thing with the other door switches is that they have a 5-pin connection on them...FR door has 2 pins I can tell appear to run to the drivers door and hook in with the corresponding switch, but I can't figure out how they function using the other wires...?

I'm not sure how to edit my notes above, so I'll just add that I did swap 4/5 with 6/7 and the FR switch now controls the driver's window.  The FL switch will lower the passenger's window, but it won't go back up.  So, you just have to reach over and press the button on the passenger's door to roll that one back up.  Well worth a minor inconvenience to save $200!

Again, proceed at your own risk...


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Last Updated:  7-6-06