J100 LC100 – Rear power window electrical issue / battery drain

[Deady]

Hello everyone,
I recently purchased a Toyota Land Cruiser J100 4.2 diesel (2003) and I am experiencing an electrical issue with the power windows.
The rear power windows (both left and right) do not operate at all. I have currently removed the two rear window fuses because, when installed, they cause a parasitic battery drain. Additionally, with those fuses installed, the front power windows also stop functioning.
Despite this, in both rear doors the speakers, interior courtesy lights, and central locking actuators are all working normally. Only the window motors/regulators are inoperative on both sides.
This suggests that power and communication to the rear doors are present, but the window circuit itself is affected.
Has anyone encountered a similar issue on the J100? I would appreciate any insights regarding possible causes such as the power window relay, master window switch, body ECU / integration relay, or wiring loom issues (especially in the door hinge area).
Problem is only on rear windows, front windows work good.
Thank you in advance.

 

[AARONTLC]

Hello everyone,
I recently purchased a Toyota Land Cruiser J100 4.2 diesel (2003) and I am experiencing an electrical issue with the power windows.
The rear power windows (both left and right) do not operate at all. I have currently removed the two rear window fuses because, when installed, they cause a parasitic battery drain. Additionally, with those fuses installed, the front power windows also stop functioning.
Despite this, in both rear doors the speakers, interior courtesy lights, and central locking actuators are all working normally. Only the window motors/regulators are inoperative on both sides.
This suggests that power and communication to the rear doors are present, but the window circuit itself is affected.
Has anyone encountered a similar issue on the J100? I would appreciate any insights regarding possible causes such as the power window relay, master window switch, body ECU / integration relay, or wiring loom issues (especially in the door hinge area).
Problem is only on rear windows, front windows work good.
Thank you in advance.

40 Amp fuse blown? Sounds like you have a pretty good short going on. You need to get something in place of that 40A fuse that can read current or indicate the short is on. Disconnect one rear door switch at a time. If short disappears, short is within that door (remove door card and inspect). If this does not remove the short, then you are looking at the harness from the door switch toward the battery. Most likely you have a short in this leg. Wires in the rubber door boot which have fatigued and shorted together? Check this stuff and then report back. Good luck!

 

[Deady]

40 Amp fuse blown? Sounds like you have a pretty good short going on. You need to get something in place of that 40A fuse that can read current or indicate the short is on. Disconnect one rear door switch at a time. If short disappears, short is within that door (remove door card and inspect). If this does not remove the short, then you are looking at the harness from the door switch toward the battery. Most likely you have a short in this leg. Wires in the rubber door boot which have fatigued and shorted together? Check this stuff and then report back. Good luck!

View attachment 4059783

On the passenger side there are separate fuses for the rear left and rear right windows, I believe two 20 A fuses. These fuses do not blow, but when they are installed the vehicle has a high parasitic current draw when switched off, and the batteries discharge within 1–2 days.
When I remove these fuses, the vehicle is fine. Even if only one rear window fuse is installed (rear left or rear right), the battery still discharges. The same happens if only the opposite side is installed.
thanks