left ignition on now GP light does not light up

[H0ss]

I have a M1028. A while back I was tinkering with the truck and left the ignition on (engine not running) for SEVERAL minuets. maybe 20-30. I have read in the TMs that this can cause issues.
At first the "wait to start" light would light briefly just a second or two. now it does not light at all.
I live in FL and it is summer so I have no issues starting the truck. It turns over for a few seconds and fires up. After it is warmed up, starts like a modern Fuel injection system the rest of the day.
(before i left the key on the "wait to start" light would light for a 10sec or so i would hear the relay click on and off when starting the truck for the first time for the day. the rest of the day No GP action needed.
I am planing a road trip in the truck from FL to UT in Oct for some over landing and want to make sure I don't have any issues with cold starting the truck.

My question is what usually goes bad with the GP system when the ignition is left on longer than (2) min?
Control Boad?
Relay? (easy to check)
GPs burn out? (I will omh out soon) This truck has less than 20k miles and was from NC so I assume it has original/factory GPs

Side note..... I have 37s on the truck anyone have any data on what I can expect for MPG on highway? 55mph-65mph cruise speed. 1000-1300lbs cargo

 

[cucvrus]

Hard to tell. I would start ny pulling the glow plugs and getting an eye ball on them. Bench test them and just 1 or 2 can cause a start issue. That is where I would start. Also check if the power is getting thru the glow plug solenoid on the firewall to the glow plugs when the wait light is on even briefly. Good Luck. Report back. Be Safe.