Thanks, it was what i thought. I am 100% sure the potentiometer is flawless as it was modulating correctly when problem was present. The pattern when the bug is present is controller hot. With the accelerator fully actuated, the truck will drive but like it was on the brakes so it will accelerate slowly and after the timer set at function #3 timer has reach the end then 1A is closing while the truck has not reached the correct speed. I have probed output of REC1 and noticed that 1A closes even if rec1 is at 50% output (24V to 30V). I suspect REC1 becomes resistive while getting hot but the oscillator card doesn't see it so the countdown of function 3 occurs normally. Am I all wrong or does it make sense? I dont like replacing parts like a guess until I find the good one. Thanks a lot all.