97 Trooper transmission stuck in "Power" mode

[Rick Rose]

Anyone else had this problem? Has my transmission guy stumped. Can get it to normal mode by hitting the button a thousand times or so, but then it goes back to power almost immediately. He's trying to find a replacement switch, hoping that will solve the problem. Next he's going to try the TCM. Any suggestions?

[amigo-2k]

try to pop the switch out and unplug it and see what happens.

[Rick Rose]

Actually, I'm running around with the switch popped out right now. By running a test light from ground, I can mimic the functions of the buttons. Pretty much the same story as using the power button, hower. Can get it into normal mode after a lot of monkeying around, and it stays there until I switch off the ignition. Sometimes it stays there even after, but usually it goes back to power mode. I'm not absolutely positive all my button pushing, test grounding is even doing anything--it may just be randomly popping in and out of the power mode. Note that the indicator light goes on and off exactly as it should for power mode, but it doesn't correlate to what the transmission is actually doing.

Thanks for the suggestion. Any further thoughts?

[fourwd1]

Since the Power/Normal system is totally electronic, it (almost) has to be the switch. The fact that you can get both modes to work implies the PCM is OK.

The switch is a simple DPST (Double Pole Single Throw) switch, with the 2 sides connected together and going to ground (Black wire) on one side. The Violet/Green stripe and Violet/Red stripe wires go back to the PCM from the other side of the switch.

To verify, you can make it work in one of the modes by just pulling the switch out (this would be the "default" mode). To make it work in the other mode jumper all 3 wires together.