I’m having a problem with my transmission going into lock-up. I’ve got an illuminated mystery switch that is wired up where if I flip the switch (ground the computer wire) it will light up the switch, (and lock the converter in theory) also when the computer grounds the wire it will light up the switch. In short if the light is on the converter should be locked. I don’t use the switch much, but I like that it lights up when I’m in lock up. Recently the switch will light up but the converter will not go into lock up right away. It may work fine, it may take a few extra seconds, or it may take longer, (I’ve had it not engage till I was doing 76 mph under light throttle, light was lite from 47mph) I’ve got 2 codes in the computer 1. P1765 trans. 12 volt supply relay circuit 2. P0743 TCC solenoid trans relay circuit. I’ve talked to a Dodge trans tech; he said it sounds like the TCC 3-4 shift solenoid. I know these trucks have a lot of problem with the TPS. My question is if the TPS was causing the problem would the computer get a ground signal, (lighting my light) and still not allow the converter to engage?

 

Are you using a double pole switch?
You have to feed the light and the lockup off two seperate circuits, four terminals on the switch or it won't work due to current feeding though the light bulb to the lockup.

 

Yes, the switch does have four terminals. The switch has been in and working properly for over two years. The only reason I mentioned the switch is, because it lights up, I know the computer is sending a ground signal. My question is when I engage the switch, even if there is a defective TPS or speed sensor, shouldn't the converter lock up anyway, because I'm sending the ground straight into the trans? I only mention the light because, if my thinking is correct, it shouldn't light up if any of the external sensors are bad because the computer wouldn't make the ground to the trans. (Does that make sense, I think I'm confusing myself)