M998 New Smart start Box installed but no wait to start light or power?

[COM998]

New to the forum, just like half the other threads I have read the past two weeks.
Brief history
Bought a M998 from Gov Planet that started no problem for a few weeks.
Old PCM burned up the glow plugs and it would not start.
Installed new glow plugs and made a ground wiring harness at the same time and it started a few times then no start with white smoke while cranking.

Just recently replaced the controller with a new Smart Start and matching TSU. After the new box was installed reconnected batteries again there was no power to the ignition switch, no wait to start light, no cranking. The truck was in neutral and lights would also not come on. Unconnected batteries and disconnected new smart start and TSU unit and then reconnected all the new items again with the batteries last. Truck wait to start light came on, went off, cranked and started immediately! Ran for 20 minutes and parked. When we came back to the vehicle an hour later there was no wait to start light, no crank, lights etc. Checked the batteries and they are tight and read 24 + volts. Unhooked everything again then reconnected but no luck.

Few questions.
If the neutral switch has failed will the truck wait to start light come on or does it cut all power to the ignition switch and vehicle lights etc?

Any other ideas? Or where should I trace power to the switch?

Thanks for your input.

 

[joeberg]

Sounds to me like its potentially a ground issue. I would check all your grounds and consider adding a new grounding harness. .

Edit: Sorry. Just reread and see that you already did this. I would still double check the grounds though, especially to the smart start. I have revived 4 and 2 of them had similar problems caused by grounding issues.

 

[riderdan]

The wait light is not affected by the neutral switch. Whether the switch is bad or not, the wait light should still come on. And obviously your other problems (no other lights working) aren't related to the neutral switch.

Sounds like you already have a grounding harness, so check that the connections are clean and tight. Intermittent electrical gremlins are often down to that. Once you're sure that's alright, time to start tracing.

 

[joeberg]

I also had one that acted similar and the problem was a loose terminal on the run switch.

Sent from my Pixel XL using Tapatalk

 

[NDT]

Check the wires coming out of the Amphenol connector on the start box, they can get corroded, have cold solder joints etc, and become intermittent.

 

[COM998]

Amphenol connector

Where is the amphenol connector on the start box?
Update as follows. Checked the ground and all seem fine on both the old harness and and new one I put in not too long ago.
Took the new smart start and TSU off and replaced with the old one and all the lights worked, turned over etc. Will not start since it is not energizing the glow plugs.

Switched out the old Protective controller and TSU and back to the new SSS and TSU- same issues. No lights, no power to wait light and will not turn over.
Going to go look over the manual and check the continuity and resistance in the wiring harness but not sure why it would connect to the old system but not the new one with the exact same plugs?

Sorry I know where the amphenol connectors are but wanted to see if you had a specific wire I should be looking at?