posted May 2019

1st Gen 4Runner (84-89) Rear Window

Note that many of the details here apply to the 2nd Gen 4Runner as well, however the specifics such as wire color and relay location are not exactly the same. Special thanks to 4Crawler and the information contained on his website for guiding me through the trials and tribulations with my own 1985 4Runner.

The rear window operates off of a standard power window motor (compatible with many driver's door and driver's side rear passenger motors from many Toyota vehicles at least through the mid-nineties. If replacing, it's best to grab a rear passenger motor as they are less used than a driver's door motor). The motor works by switching the 12V polarity on the two wire leads. The motor is mounted directly to the regulator in the rear tailgate.

The polarity to the motor is controlled by a set of relays in a control box. The control box is located behind the rear passenger panel on the driver's side. The relays take the low current input from either the keyed switch on the tailgate or the center console switch and provide the proper polarized power to the window motor. The switches operate by common ground. The up and down terminals are powered at 12V and the common terminal is grounded to them with the switch is pressed or key is turned. The up and down terminals on the keyed switch in the tailgate are powered at all times. The up and down terminals on the console switch are powered only when the ignition is on. A common modification is to modify the leads to the control box that contains the relays such that the console switch is powered at all times.

The system has a set of safeties built in that control whether or not the common terminal is grounded. If one of the safety mechanisms is open or faulty, no ground will be provided at the common terminal and the window will not function via normal operation.

  1. Rear Wiper Retraction Detection Switch
  2. Door Lock Detection Switch
  3. Cover Top Switch
  4. Window Lock/Child Safety Lock (2nd Gen only)

You can bypass all safeties at the console switch by simply providing a direct ground to the "middle" wire of the switch. The switch has 5 wires that run from top to bottom. Wires 1 and 5 are for the backlight 12v+ and -(typically G and R respectively), 2 and 4 are the 12v+ wires for the up/down leads (typically R/Y and G/Y respectively), and wire 3 (the middle wire) is the safety provided ground (typically L). This is not a recommended solution and is intended solely as a test if the safeties are the problem.

The Rear Wiper Retraction Detection Switch is unique in that it is open when the wiper is fully retracted. This means that you can bypass this safety mechanism by simply unplugging the wiper motor at the driver's side rear corner where the shell meets the body. This switch detects that the wiper is fully retracted and out of the way for safe operation of the window.

The Door Lock Detection Switch is located inside the driver's side latch of the tailgate. When the latch is closed, the switch is closed and provides a ground to one leg of the Cover Top Switch. This switch can be bypassed by unplugging it and then jumping the source ground (W/B) wire to the blue wire on the vehicle harness. This switch can be taken apart and refurbished if faulty. The switch may be tested by checking for continuity between the terminals when the tailgate is closed.

The Cover Top Switch detects that there is a bolt in the 2nd from the rear whole on the shell. This switch may be bypassed by jumping the two terminals and may be tested by checking for continuity between the terminals.

Console switch works but key switch does not?

This is caused by grounding the console switch to an alternative to the switched safety ground. The keyed switch is still relying on the safety circuits and isn't getting a good ground. Fix the safety grounding system and you should restore the keyed switch. It is also possible that the keyed switch has failed. Before replacing it, test all the grounds first.

Window doesn't work if lights are on?

This is caused by grounding the console switch to the backlight for the switch - this seems like a common modification when a previous owner had an issue with the ground and they fix it by swapping the leads. Typically another symptom is also that the keyed switch doesn't work at all. This is because the keyed switch is still relying on the safety circuits

Modifications

Console switch always hot [reference]

Find the ignition power lead at the control box, it should be the red wire in pin 8. This will not be a very thick wire as it only sends a signal to the relay. Find the Battery 12V lead at the control box, it should be the thick blue wire (no stripe) at pin 6. Cut the red wire for ignition. Cover the end of the wire coming from the ignition and splice the end going into the control box to the blue wire for 12V battery.