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clint
08-24-2009, 12:18 PM
i know this has been done before on other sites, but i found it very useful to me, and most of the other threads i found lacked a diagram for wiring the switch itself. i figured i would share this for the benifit of anyone with a 1st gen runner.

When I bought my ‘87 4runner the tailgate window glass was not in tracks and flopping around loose in the tailgate. The previous owner had stuffed a folded up chunk of garden hose to wedge the glass into a stationary position. I popped the inspection cover off and looked inside. The regulator was severely corroded and wiring to switches unplugged and damaged. I also noted the vertical glass runs on either side had broken free of the tailgate shell in both mount locations and were laying in the bottom of the gate. Typical Toyota corrosion. Rusted right off. Leaving two small rectangular rust holes on the edge of the gate on both sides. First things first needed a gate that had glass run channels in it still and hopefully complete reg and motor assembly. Found a used tailgate from a fellow parting out a 4runner about 45 minutes away in victoria. When called he said the gate was also rusty and he didn’t want to sell it because of the rust. Bought it anyways, got it for $40.00 it was much more to work with than mine. Run channels reg, motor etc all there. Electrical condition unknown. Stripped my old rusted gate of harness and reg/motor. Separated the motor from the regulator, tested it, its good. Spare. I swapped and hooked everything up, tried switch - no dice. So I grabbed a battery and some wire, and jumpered the motor direct. Worked good. Checked all interlocks and safety switches. There is a safety switch that controls the tailgate window in the rear wiper park circuit, the tailgate lock mechanism, as well as a manual switch to “lock out” the window switch as well as a side bolt hole for the hard top has a switch in it to ensure the top is bolted on before the relay will power the tailgate window motor. Did some checking and there is a multi-function relay that controls the window as well. It is located on the drivers side, in the body about knee height for the back seat passenger right behind the trim panel on the interior quarter behind the doors. Tested relay with test light and determined with all safety switches either functional or bypassed I was getting power into relay but never out when trying the switch. Bad relay. I Googled it, and apparently is a common issue. Apparently the relay is quite expensive from Toyota and difficult to get used. When I looked online I found several possible solutions for the relay, ranging from an omram part number for the relays individually inside this multi-relay module to replacing the circuit with a momentary-on two position switch. To do so requires a double pole double throw switch with momentary-on both directions. Sounded like a simple enough repair. Went to wire up, and the only issue I had was determining the way the switch I purchased was internally switched. There were six terminals on the switch and no instructions., the catch is there is no ground circuit on the 4runner window motor, the motor changes direction by reversing the polarity of the motor to change the motors rotating direction. Consulted with a friend who’s wired these switches up, and have now a diagram for cole hersee part # 55054 dpdt mom-On switch. I chose to use a heavier gauge wire than I likely could have gotten away with. I ran new wire for the entire circuit, because if I come across a used relay module or part out a 4runner with a good module, I wanted to not damage any of the existing circuit and keep all factory equipment in place. I removed the pigtail for the motor connection from my other t/gate harness, and ran 10ga wire, red and black from the motor through the stock harness locations up the inside trim on the drivers side to the under carpet junction that branches off to the console, up under the carpet to behind the lower dash heater outlet and up to the switch mounted to the right of the steering column on the dash. From there I had already run two more wires from there, up under the dash behind the glove box and behind the ecu located behind the lower passenger side plastic kick panel trim. I followed the stock harness from there through the firewall grommet and to battery. I am going to add an inline fuse assembly to the cable near the battery and perhaps construct a weather proof accessory junction box near the factory under hood junction block. Then I will have fused capabilities for electrical accessories and can label and draw diagrams for it. Once a friend had shown me the switching, wiring the switch is simple. The polarity reversal operation is achieved simply by crossing over the switch diagonally with jumpers to change the polarity. After installation the only concern anyone would have with this repair is that there are no longer any safety or functional interlocks on the system so the switch should be mounted in a manner that items or debris cannot accidentally activate circuit.

the motors direction of rotation is controlled by the polarity of the current flow, the positive and negative to the battery are irrelevant to the actual wiring, I showed colour from the battery for reference only. the total cost of this modification was less than $40.00. The switch was around ten bucks, and there were several shrink terminal connections and several meters of wire. I strongly recommend installing inline fuses or running circuit through a fused junction box if available. Im never really a fan of connecting accessories directly to the battery if it can be avoided. As I mentioned earlier I am going to modify and mount an under hood circuit box for all the electrical accessories I am installing. I strongly recommend care taken in all electrical installs to prevent “thermal event” (fire)