Doing some electrical diagnostics on the BJ74 Power windows....could use a little help

[deepseacruiser]

So having a right hand drive landcruiser with a passenger window that doesnt roll down is becoming a pain here in the states.

Currently the only switch that works is the auto up/down on the driver's side. All other functions do not work. I pulled out the manual but the diagram in the chassis manual is incorrect for the RHD BJ74.

I began a little diagnostics with the multimeter by checking for continuity/voltage on the passenger switch, but without a the wiring diagram I am unsure of which pins to check.

I also checked the voltage going to the window motor and I get increasing voltage going to the motor when I press/hold the up switch, but none when I hit the down switch. There is also a small capacitor inline with the window motor.

My understanding is that with a two wire motor the up/down switch should just switch polarity to operate the motor up or down?

If anyone can make sense of what I am talking about or has the correct wiring diagram that would be very helpful.

MY next step was going to be to apply 24v directly to the motor and reverse the polarity and see if it will go down. IF this is the case the switch just may be old and corroded?

I will post pictures when i get home as well

 

[Gun Runner 5]

Just curious, what year model BJ74?

 

[deepseacruiser]

10/88 build date

 

[Gun Runner 5]

10/88 build date

Cool..... My antique (1987) still has manual windows.

 

[dabasscow]

Could just be the switch, if your gentle you can pull switch apart, there are little plastic things that push the brass bits on to the contacts if these are broken they won't allow contact. Mine doesn't have the auto up down for the passenger side.

 

[Oldtoy74]

 

[Shes Mad]

My Passenger window would not go up and down on my 85 BJ74. I took the door apart, and applied 24V directly to the window motor, and it went up and down fine. Thought it has to be the switch, because it would not power at either door. I went to the drivers door and prepared to start tracing the wiring to find the break.

It was then that I noticed the window switch on the drivers door was off. turned it on, and everything worked fine.

That switch just cuts the passenger door. It kills both the switches that operate the passenger door window. So if it is off, Turn it on! If it is on, check it first to make sure it works

 

[peterb]

Deep$%#t
Another thing to try is taking the swiches apart and cleaning the contacts. On my truck the two switches that operate the passenger window had sparked enough to prevent the flow of current. Just clean up the contacts with a little steel wool and hopefully you should be good to go for another 25! My truck is two months newer that yours.
Peter

 

[deepseacruiser]

Oldtoy, thanks for the proper wiring diagram. I will do some diagnostics when i get a chance.

Update. I cleaned the contacts which looked to be in pretty good shape, no change. Made a jumper wire from the battery to the switch and operated the passenger window up and down by switching polarities(pos to neg)

Possible bad switches or broken wire some where, wont know till i perform some checks.

My panel are in pretty rough shape and was planning to replace them with HDPE plastic sheeting and source aftermarket 24v switches. Any ideas?

 

[deepseacruiser]

From the wiring diagram that old toy posted it appears that a failure in either the window lock/master/passenger window switches can cause the whole passenger system to not work. I wish I still could trace wires like I used to on the soon to be retired P-3's

My plan is to change the switches to marine contura switches. Correct me if I am wrong but it appears I need a SPDT(mom. ON-OFF-mom. ON) for the passenger side switch and both drivers side switches, a regular SPST(ON/OFF) for the window lock. I could either eliminate the auto up/down or install a switch for that as well.

 

[SeanBJ74]

So my power window motor is working fine, but I had a spark yesterday in the cable that goes into the switch. Do I just need to replace the cables going from the power motor window to the switch ? Having the windows stuck on up with no AC is not fun haha
1986 BJ74, RHD, auto