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i have reason to believe its the proportioning valve???
does anybody know if the proportioning valve sends a signal to the pcm to disengage torque converter lockup?????
Well, the RABS computer will turn the ABS light on if it doesn`t receive a brake light on and off signal and the torque converter lockup is disabled when the PCM receives a signal that the brake lights are on.
However maybe you have two unrelated faults, one in the RABS and in the lockup circuit.
Maybe try checking for any trans related trouble codes (use the self test if you don`t have a code reader).
How would it be a PSOM problem?
i like the thought but idk how that would cause no torque converter lock up....
If the PSOM is bad it may load the VSS circuit and cause the RABS module to turn on the Yellow lamp.
Also if the PSOM is bad it would not send the speed information to the PCM Computer and then the PCM would not lock up the TC.
It would also shift hard and the speed control would not work.
"Brake light switch always closed" Service circuit 511 Open/short
Service brake switch.
Circuit 511 = light green wire between the brake light switch and the rabs module. According to my diagram it tee's off down stream of the stop lamps, so based on that this statement It isnt a brake switch, it works properly would be a possible and suffer the condition you describe. IE brake light switch and lights work, but TCC won't lockup.
SOLUTION!
i have l.e.d. tailights on my flatbed. usually you need a resistor when installing leds so that the abs module and computer can detect that your tailights are functioning. improper functioning of tailights will DISENGAGE tc lock.
since i dont run resistors, my computer relies on the third brake light to create the resistence needed for it to detect that my tailights are functioning. turns out i had a bad connnection to my third brake light.
i fixed that and now i have tc lock up again