ok my 97 1 ton dually 2wd diesel is having some issues i need fixed ASAP.

the gen light comes on and then the tach bounces all over the place and the volts gauge will move around from 10.5-15 volts and the ALL the lights will either dim or flicker or go off and then come back on and also the trans will shift and unshift?

what can cause all this??

both batteries are brand new.

 

Check the wires to the crank sensor.

 

is the crank sensor what will cause all this?? is there a way to tell if the sensor is bad?? thanks??

 

have the alternator tested, sounds like the voltage regulator is going bad.

 

Voltage regulator is in the computer. Agree with wanna ^ Look at the crank sensor and wiring. The computer relies on this info to determine charging voltage and the such.

 

oops! hit the post twice.

 

will look at the wires and sensor. the ALT is working i know that.

how do u check the sensor??

thanks

 

Hard to test the sensor if its intermittant. Basically its sent a 5V power source and is switched on-off with the recess in the damper. Three wires IIRC.. If it has been rubbed on the crank, it may be damaged. Also the wires may rub through near the front of the engine where its not in loom. Vibration kills the wires.

 

in the book the CKP was only on 99 and later models mine it says its a VSS. the sensor ontop of the damper thats what i should be looking at right?? also what should the gap be between it and the dampner?? i tried to stick a credit card inbetween and it barely went.

thanks

 

i checked the wires and they look fine. i tightened the battery terminals up and checked it all over. turn the key to the on position the volts gauge sits at like 10.4 volts and u can barely get the windows up but the truck will start right up. then it will jump up to 14.0 volts or more or maybe a little less. and with the truck just sitting and ideling or even driving the volts will jump all over from 10.4 volts to 14.7 volts. it just keeps jumping all over and the lights flicker constantly. and every time u hit the brake pedal the lights flicker. would this be the light switch??

thanks

 

It sure sounds like a voltage problem. The batteries are only as good as the weakest one. Unhook them and test each one separately. Also check all of the wiring going to the alt. There could be a loose connection at the back or a wire going to ground somewhere.

 

both batteries are brand new. it did this before i changed the batteries also.

joe

 

By chance are your grid heaters cylcing? That would be enough to lower batt. voltage that low. Light switches were a problem in the 2nd gens. Do you have an overhead console? Watch the outside temp when it acts up. Might be why the grid heaters are cycling too. Had the codes checked? The PCM regulates the voltage and something could be going on there as well.

 

It looks like you did some work on the front already so its possible the Crank sensor on the damper got damaged. If it got swiped by the crank, it would be spotty. Should be around 0.050" gap to the crank IIRC.. I wpuld pull it off and see if it has been swiped.

 

this is a different truck than what i have in my sig. this is a 97 1 ton dually flatbed 2wd. with 290,000 miles

i just checked the headlight switch and that is fine. the power wire is run into a relay when i pulled it out and also the light switch has an extra ground on the switch. my other 97 didn't have this stuff is there a reason??

how do u check if the grid heaters are cycling?? and yes i have an overhead console. i haven't noticed the outside temp act up. i will check that out.

its not spitting any codes out at all. it was hooked up to a computer and also it didn't show any shorts anywere also.