Attention: TDR Forum Junkies Pulling boat back from Alabama last week, ('98 12-valve) I could not get cruise to work. The light wouldn't even come on. Also noticed no tach and the horn wouldn't honk. I suspected the clock spring for the cruise and horn, but that didn't explain the tach. No fuses specific for any of this stuff (except horn, and it was good). Did the instrument cluster self-check, and all was good (including the cruise control light). Following FSM procedure, took off the steering wheel and removed the clock spring. Continuity check through all pins was good. Cruise switch resistance readings were within tolerances stated in book. Put it all back together and the horn worked but still no cruise. (Must not have pushed horn button hard enough earlier.)
With no more help from the FSM, I renewed my TDR subscription so I could do a search. On about the third page, one of the posts said that failure of the engine speed sensor will shut down cruise control, tachometer, voltage regulation and keep the A/C clutch from engaging. Went back out to verify, and sure enough, with engine idling, the volt meter showed battery voltage, the a/c didn't work and of course, no tach or cruise.
Got the new speed sensor, installed it, and now everything works again.
Nothing in the FSM gives a clue that the PCM uses the speed signal to control all this stuff. The closest it comes is to state that '98 models do not use the vehicle speed sensor for cruise control, but instead uses the rear wheel rotation sensor. (I knew that wasn't bad, because the speedometer still worked.)
This isn't the first time TDR has saved me time and money; guess I won't let my subscription lapse again! The other thing is that the FSM does not have everything you need to know to fix your truck!
With no more help from the FSM, I renewed my TDR subscription so I could do a search. On about the third page, one of the posts said that failure of the engine speed sensor will shut down cruise control, tachometer, voltage regulation and keep the A/C clutch from engaging. Went back out to verify, and sure enough, with engine idling, the volt meter showed battery voltage, the a/c didn't work and of course, no tach or cruise.
Got the new speed sensor, installed it, and now everything works again.
Nothing in the FSM gives a clue that the PCM uses the speed signal to control all this stuff. The closest it comes is to state that '98 models do not use the vehicle speed sensor for cruise control, but instead uses the rear wheel rotation sensor. (I knew that wasn't bad, because the speedometer still worked.)
This isn't the first time TDR has saved me time and money; guess I won't let my subscription lapse again! The other thing is that the FSM does not have everything you need to know to fix your truck!
