I have a 90 Chevy 4wd with 5.7l and 700r4 tranny. Apparently I am not getting 12v power down to the torque converter via the wiring. My question is - what controls it? Is it involved in the switch on the brake pedal or is it electronically controlled somehow. Will it be easier to run 12v down to it and use a toggle switch to lock it when doing highway driving in OD? Any info on a temporary or permanent repair helpful!
You should be able to flash your code with this page troublecodes /GM/
Is your TV cable adjusted correctly? That can control shifting.
The lock feature on your transmission is controlled through the PCM. (Power train Control Module) If you can run a scan on your vehicle it will tell you what is wrong. While the 700R4 is not an electronically controlled transmission, the lockup feature is controlled by the PCM. The proper adjustment of the TV (Throttle Valve) cable is critical as it controls shift points and line pressure. I hope this helps.
People are retarded. 700R4 is not PCM/ECM controlled. It has a TV cable to control line pressure. TCC itself MIGHT be controlled by the ECM, just depends. What is the part number of your ECM? Non-ECM TCC controlled 700's use a vacuum switch on the firewall (manifold vacuum) and a switch on the brake pedal to disengage. Do not run a toggle, fix the problem. You can ruin the TCC easily, because the clutches in it are not very strong nor large, and will burn if used improperly.
