How do i jump the starter directly on M939A2?

[1 Patriot-of-many]

I'm not getting any starter solenoid thunk when hitting the start switch. I'm going down the TM troubleshooting list, battery switch is good, starter switch is good, I get the thunk from the PCB, have 24 volts to the solenoid. Want to skip ahead...... Can I bypass the solenoid somehow and apply current to the starter to see if the starter itself is okay and work backwards from there? I'm assuming at this point the solenoid is the culprit or neutral safety switch possibly.

 

[simp5782]

I'm not getting any starter solenoid thunk when hitting the start switch. I'm going down the TM troubleshooting list, battery switch is good, starter switch is good, I get the thunk from the PCB, have 24 volts to the solenoid. Want to skip ahead...... Can I bypass the solenoid somehow and apply current to the starter to see if the starter itself is okay and work backwards from there? I'm assuming at this point the solenoid is the culprit or neutral safety switch possibly.

Yes. With a screwdriver or a remote start hand unit you just go from the big + post on the battery to the little signal wire right next to it.

You simply just add a test light on the signal wire at the starter and see if you have power for the start signal at that wire when you hit the starter switch in the cab

 

[1 Patriot-of-many]

I'm stumped. I get 24 volts from the red main wire from the battery to any of the terminals whether the starter switch is on, off or in start position. Which terminal should I jump from the red main wire to crank over the engine without the solenoid involved? The big one connected to the solenoid directly underneath the red one?

 

[gimpyrobb]

Probably to the one that says switched.

 

[Floridianson]

If I remember one that does not say switch is a ground. I like remote starter switches as I have seen where someone used a screw driver and it messed up the threads. Now when you have to take the starter out it becomes a problem. Never use a screw driver between the two large lugs as it can weld the screw driver to the lugs and the starter will keep spinning till you break the weld if you can.
Hook to the top big red one from the battery and the switch lug. You don't want to uses a screw driver between the two big lugs. Sparks will fly!!!!!!!!

On the 250 Cummins and the 400 Cummins mechanical engine we run the thumb screw in to bypass the electric shut down. So to use remote starter switch, screw in thumb screw, turn on master and starter switch to run then use remote switch. Motor will run. On the 8.3 I thought there was a way to make the electric shut down retract but double check me as I have no mind left.

 

[74M35A2]

Wow, older starter. That solenoid likely has an isolated ground, as mentioned, and I am guessing same as gimp that it is the small terminal closest to the engine. That wire was already modified once, as it has a crimp on terminal on it, which can be OK.

You don't need to go back to the battery to do this. Just run a short wire from the top longer large solenoid terminal (large cable with red marker) to the small solenoid marked switch. It should crank. If not, next you can do it again, and this time also connect a ground wire to that right side small solenoid terminal, just in case the ground link is weak on that circuit.

I side with Floridianson, not fabulous to jump the 2 large solenoid terminals, unless absolutely emergency necessary. This is a correction update from my previous take on it.

 

[1 Patriot-of-many]

Wow, older starter. That solenoid likely has an isolated ground, as mentioned, and I am guessing same as gimp that it is the small terminal closest to the engine. That wire was already modified once, as it has a crimp on terminal on it, which can be OK.

You don't need to go back to the battery to do this. Just run a short wire from the top longer large solenoid terminal (large cable with red marker) to the small solenoid marked switch. It should crank. If not, next you can do it again, and this time also connect a ground wire to that right side small solenoid terminal, just in case the ground link is weak on that circuit.

I side with Floridianson, not fabulous to jump the 2 large solenoid terminals, unless absolutely emergency necessary. This is a correction update from my previous take on it.

Excellent guys I will try that soon from From Big RED to SWITCH on the solenoid with a pair of jumper cables. Then if nothing, clean what you guys are referring to as the ground wire on the right and run a new wire to ground from that connector.... Appreciate the help guys, I'm just scared of shorting something out and making it a bigger job. Will update when completed.
Yeah I was looking at new starters and they don't have all these cable connections......

 

[Floridianson]

Jumper cables might be to big or cumbersome. Just a foot long piece of wire is enough to make the trip.

 

[1 Patriot-of-many]

You guys are geniuses, okay don't get big heads, I was being hyperbolic...... Used a piece of 14 wire from big red to the switch terminal, Started right up!!!!! I thought for sure I was going to have to put a new starter in. Anyway that I think confirms there is a break or ground on the wire that goes to the switch terminal........ THANK YOU GENTLEMEN! Big green thanks you too, She hasn't been run since last fall.....

 

[74M35A2]

There is a solenoid in the PCB that controls this signal, and may he bad, even if you do or do not hear it clicking when actuated. Start there is you have not yet. They are readily abailable and not difficult to replace.

 

[1 Patriot-of-many]

There is a solenoid in the PCB that controls this signal, and may he bad, even if you do or do not hear it clicking when actuated. Start there is you have not yet. They are readily abailable and not difficult to replace.

I did replace that first but it was supposedly a known good take out..... I have anotherr that's supposed to be tested good also, guess I'll check that wire for continuity first before I go through the trouble of replacing yet another and also test the pcb before I in bolt it. I should've tested before I installed it. Story of my life, day late and a dollar short. Does the wire to the switch lug on the solenoid go through the neutral safety switch as well?

 

[74M35A2]

They are low cost enough new, to not be using used ones. They are a limited life part.

I would have to look to confirm, but the neutral switch should be tied into the dash starter switch circuit, and not the “after” the PCB, as there would be no reason to run higher under hood current through the neutral switch. Download the P2P program to confirm, it is great for the questions you are asking, and easy to use.

 

[Swamp Donkey]

Neutral start switch is tied into the Start switch and the PCB by wires #498 and #499.

 

[rosco]

It wouldn't hurt to remove all those wires & clean the terminals, adding diaelectric grease, so you know the connections are good for another 20 years.

 

[1 Patriot-of-many]

Update cause I hate when people just walk away without telling you what was wrong. I pulled on one of the wires going to the neutral safety to disconnect it from the shell connector and it pulled out of a prior crimp connection fix up further. So I put a new shell on a new wire and did a two ended crimp to the wire that pulled out. Still nothing. So I decided to just bypass the Neutral safety switch altogether temporarily, Started right up. Neutral safety switch is bad. On another note I know there are previous wire fixes going to my 5th gear lockup solenoid that might explain why I get no lockup in 5th gear limiting me to 55 mph or so. Man it's a bitch trying to get to this stuff as a 270lb fatass and I'm guessing as a 150lb soldier it's still a bitch to reach up there around the transmission!