1992 3.9L D150 with A998 three speed auto - My check engine light is on and the code is open or short circuit over drive solenoid. The solenoid referenced here is supposed to lock out the torque converter. I replaced the solenoid without any improvement. I can't find this solenoid in the wiring diagrams in the Haynes book. It is a single wire and it is dark blue with a yellow stripe. The only such wire in their diagrams goes to the fuel shutoff relay and fuel pump relay. There is no mention of a torque converter locking solenoid anywhere in any of the diagrams. The only transmission control wires in the diagrams are of other colors, and of course the transmission itself is not included in the diagrams so I can't tell if one of those wires is supposed to be the torque converter lockout wire. The only way the PCM could be controlling the torque converter lockout solenoid is if it is one of the wire shown in the Haynes book as being some other color. I would like to hear from someone with good info or a better wiring diagram than the ones in the Haynes.

 

Hanyes wiring diagrams suck. They bear little relation to what's actually in the truck. Try here for accurate wiring diagrams, there is some hoop-jumping involved to get access, but, it's worth it.

 

Thanks for the lead. Even their diagram shows a two wire connection on the TC lockout solenoid and their wire colors are wrong but at least they acknowledge the existence of the solenoid and the relay. I cleaned the single wire and instead of blue/yellow it is actually blue/white. I was able to trace the wire and found it attached to a relay located underneath the hood hinge on the inner finder - driver side. I searched for that relay part number and found it listed as being no longer available/discontinued. I searched a while longer and found another relay with the same pinout format, even with the same terminal numbers. I've ordered one and will see if it works. I think possibly the only difference is the lack of a mounting bracket but If it works I can wiretie it in place. If changing the relay doesn't work I'm back to scratching my head. The single wire solenoid has to be grounded thru the transmission. Another thought I've had is to add an additional grounding wire to assure that the transmission is properly grounded. I'll update when the relay arrives.

 

Good lead. Some of the diagrams were for a different transmission, hence the different wire colors and number of wires. When I found the right diagram everything matched up with my truck. Those are the best wiring diagrams that I've found so far.

 

Finding a REAL, hard copy of the factory service manual is best.

 

i happen to know there is a copy of the 93's service manual floating around the internet. a 92 should be the same or very similar especially since you got the 3.9