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1998-2000 LS400...Am servicing my manual transmission shifter ... the rocker switch button on my shift indicator plate is momentary actuation in snow mode but remains actuated( in down position in power mode.
Question is whether the power side should remain in down position or operate in momentary actuaion fashion as does snow mode rocker position
Thanks.
Power side remains down when actuated. Is this correct?
Working as designed, the snow setting enables 2nd gear start and softer shifts to enhance driving in slippery
conditions. Resets to normal after a restart or you can press snow again while driving. Does not stay on all winter.
Power is to have the transmission hang onto gears to higher RPM (regardless of throttle position) and also to down
shift more aggressively when decelerating. Set it and forget it if you enjoy the responses. Seems likely to affect
MPG's and on newer Lexi it also defaults off as with the snow setting.
Working as designed, the snow setting enables 2nd gear start and softer shifts to enhance driving in slippery
conditions. Resets to normal after a restart or you can press snow again while driving. Does not stay on all winter.
Power is to have the transmission hang onto gears to higher RPM (regardless of throttle position) and also to down
shift more aggressively when decelerating. Set it and forget it if you enjoy the responses. Seems likely to affect
MPG's and on newer Lexi it also defaults off as with the snow setting.
So am familiar with the system operation....
Am attempting to determine if the switch is mechanically sound.
If someone can simply actuate the rocker switch in both modes and respond whether the switch in the Power setting is momentary (springs back) or remains set in actuated position (like when you flick a light switch)
on my is250 the power is a hard switch up but there is a neutral position (middle) and down, momentary, for snow.
probably doesn't help you much haha, my 97 LS400 didn't have TC.
Am attempting to determine if the switch is mechanically sound.
If someone can simply actuate the rocker switch in both modes and respond whether the switch in the Power setting is momentary (springs back) or remains set in actuated position (like when you flick a light switch)
Thanks....
Mine works the same as yours. Power stays down, snow snaps back.
Ｔｈｅ ECU has a flip-flop inside connected from the single contacts of the SNOW switch which only turns ON when pressed. This triggers the flip-flop to set and keeps ON until the flip-flop is reset by pressing the switch again. In other words, the switch only changes the state of the flip-flop every time it is pressed.
To elaborate a bit further for the non-electronics folks, a flip-flop is an IC (Integrated Circuit), a device or a chip that's on the ECU PWB (Printed Wiring Board) & it's at the front end of the board to receive inputs & process the signals accordingly. The devices have internal built-in latches so they only need pulse command inputs & will hold the signals in that state once activated that's why the lower half of the switch is a momentary switch in the SNOW function. Other IC's do not have the internal built-in latches so the input signals will need to be a line commands (a constant high (5V) or low (0V or ground)) when activated that's why the upper half of the switch is a toggle switch when it's in the PWR position.
05-09-18, 03:01 PM
Power and snow rocker switch
