grid heater and oil pressure

What is your volt meter doing right after start up? Even at 30 and not waiting for heaters it should start in less than half a crank of the engine. Have your batteries load tested. If any weakness in either, replace both.

Your alt should be putting out 14+ volts. The grid heaters will make the gauge go down and up from 8 or 10 v to 14 when cycling, if operating. Completely disconnect the amps at the battery for a week, dirve it for an hour and then see what happens over a week or so.

Try this and get back to us. Turn the key to on, not all the way to start, and wait for about 10 to 20 seconds. Watch dash for the wait to start light to come on for a few seconds. If if comes on go ahead and finish turning to start with out turning back. Should then start right off. Report back.

That may not be an air/fuel problem. Do the wait to start test I posted above.

Nobody has any idea what may have been under there and cut out. Probably something aftermarket.
You should just pay a Viper installer to do it for you.

Is there a blue trailer brake harness plug there near the steering column? If not, somebody probably cut it out and left those wires. Find a schematic on here or Google and they will tell you what those colors go to. If you are a Viper installer how could that install be a $4200 install. Was that typo? That would be 20 to 50 hours. I do not think so, it should take no more than 2-4 hours for anybody that has done a Dodge truck before.

It likely was to the tlr brake plug.

I can't imagine rewiring the whole truck to install an alarm and remote start. Sounds a lot like dealer way over packed labor rates. I bet you do not get many of those jobs. 11 hours to install?