Odd Starting issue- older D6t

[watglen]

D6T zjb00289 2011 or 2012 model

Weirdest thing. Dozer has a habit of failing to crank. You get a a bit of clicking etc like a dead bat. Problem is most common when the machine has sat for a couple days, and doesn't present itself if the machine was run yesterday, just like a weak bat. Machine will fire if you hook a jumper cable to it, just like a weak bat.

The weird part is this. The operator discovered if you turn the key to on and let the computer get to its happy place, like normal, then further turn the key to crank and hold it there, nothing will happen for about 10 seconds, and then the machine will crank fast and fire right up. Since he discovered this, he uses it every time. No boost required.

Wtf is going on here?

TIA

 

[Simon C]

Check your ground connections to see that they are clean and tight. Battery connections also. Have someone put there hand on the Starter Solenoid when he turns the key to start and holds it there. If you feel the solenoid go clunk and does not kick back it means that the control circuit is doing its job and the solenoid coil is working properly. It does not mean that you have good solenoid contacts however. Or the starter may have a bad spot in the winding that does not go all the time. If the solenoid kicks back you will need to check the (S) Terminal of the solenoid to see if the signal voltage to tell the solenoid to work dropped out or not. Start by checking these things out first.
Simon C

 

[Bluox]

If the solenoid clicks when he turns the key to start that indicates the contacts are burnt .
May be time for a new starter.
Time to get a volt meter and do a start system voltage drop test.
Bob

 

[Birken Vogt]

You have to understand the sequence of events. How does voltage get from the switch, through the harness and various relays, finally to the starter solenoid and motor. And how is the computer involved. See exactly where the signal is still working and where it stops.