Hello Everyone,
I have tried finding what info i could searching but havent really had any luck. Im working on reviving a buddy's 1989 Pickup, xcab 4wd 3.0 and it sat for about a decade. He bought it new in 88, added the AC himself and knows the entire history of the vehicle.

Naturally, the tank was all rusted out, sensor, dummy light and pump have failed, among other things. Good news is, it sounds great running on starting fluid lol

This truck has the 19 gallon tank and the 4 wire, square configuration plug fuel level sensor/dummy light switch. These are no longer available through toyota or any aftermarket company. All that is available are the 3 wire units (that I will have to modify slightly to reach the 19 gallon capacity.

I purchased one with the intent to use the plug from the original, but I'm not sure what the extra wire is for. I am assuming it is an extra ground for something. I cannot find any wiring diagrams that show this configuration either. I know I'm going to figure it out and get the dummy light to work, but I am hoping to save a bit of time and I was curious if anyone has done this yet or figured it out? Or if anyone has the diagrams?