Instrument Lights and Daytime Running Lights Not Working

[bd]

The charging system and glow plug wiring has been significantly altered from the factory configuration.  Bear with me.

With the engine off, what is the voltage at the alternator output post?

Does the yellow wire that runs between the alternator output post and the glow plug controller connect to one of the controller studs or the four-wire harness connector? 

Which of the two glow plug controller studs always measures battery voltage?

[Double-A]

Ok. I didn't do the test where you said to jump the output post and the red wire. I just did the ones in the last post of yours.

So the voltage at the output post with the engine off and ignition off is the full 12 volts. I should mention that there are 2 wires connected to the output post. There is the yellow wire, and a thicker (maybe 12-10 gauge) black wire that goes to a ground.

The yellow wire goes to a stud on the glow plug controller.

 http://imgur.com/a/6vbrz - Picture one- In green it clarifies which wire has the volts)
- Picture 2 is my glow plug controller. The yellow wire circled in blue is the wire on the alternator stud, and the orange circled post is the one with constant voltage.
 The other post doesn't have voltage and I didn't test the wires in the connector.

[bd]

Take another look.  The alternator output post cannot be grounded if it measures 12 volts!  Are you sure that "thicker black" wire sharing the post with the yellow doesn't connect to battery positive?  Disconnect the yellow wire from the glow plug controller stud - does the yellow still measure battery voltage?

Jump 12 volts to the regulator plug "red wire" then check for power on the 12-gauge red at the bulkhead connector.

[Double-A]

I am 98% posotive that black wire connects to the output post. I cant actually SEE it but I can feel that it goes and connects there...

[Double-A]

Well I just went and rechecked. I didn't see in the dark last night that the black wire that is on the outpost connects to the positive battery terminal.

I didn't do the jump test yet, I'll try to do that tomorrow.

[Double-A]

Should I still do the test where I jump the 12 volts to the red wire?

[bd]

Should I still do the test where I jump the 12 volts to the red wire?

It's the quickest way to your solution.  When you jump power to the "red" wire, see if the running lights begin work with the headlamp switch.

BTW - Not to over stress the point, but when supplying power to an unknown circuit, it is risky to use an unfused source.  Hence, the recommendation to fabricate a test jumper "protected" by a circuit breaker or fuse.

[Double-A]

Alright. I'll probably have to do it this weekend cause I don't have any 20amp fuses laying around.

If it does supply power to that wire what would be the next step?

[bd]

If it does supply power to that wire what would be the next step?

Based on e/g we've discussed, there are several issues you will need to correct.  But, first, verify that power will actually reach the headlamp switch and the running lamps work when 12 volts is jumped as previously described.

[Double-A]

Ok. One last question before I jump the wires... To test the headlamp switch should I keep how it's setup (blue wire as power) or should I wire it with the red and white wires? (They are currently disconnected and have no power... I guess my thought is if I jump the wires then maybe the headlamps red and white pair will have pretty again)

[bd]

Initially, just jump power to see what happens.  The more changes you make between checkpoints, the easier to become confused if something doesn't work as expected.  I'll provide a list of items to correct at the proper time and assist you through the process.  It shouldn't be horribly difficult with a few proper tools, just time consuming and methodical.

[Double-A]

Ok. I will have to go get an auto resetting circuit breaker from the parts store this weekend then. You posted that a 20 amp one would be fine or would lower amps be better?

[bd]

For general use a 20-amp breaker is very versatile and will work fine.  I wouldn't go any less than 15 amps.

[Double-A]

OK. Sorry for the late response. I jumped the output on the alternator with the red wire labeled "To Alternator", this gave that wire voltage like we thought it would. However the lights don't operate with the switch that way, instead the parking lights (the orange ones) and clearance lights turned on with the switch off and ignition off. The headlights still operated with the switch.

[bd]

Is the headlamp switch still wired as imaged?

The orange wires on the headlamp switch are supposed to be constant 12 volts.  They should become hot when the red regulator wire is jumped to B+.... 

Does the 12-ga red wire behind the dash for the headlight switch also become hot with the test jumper installed?  Do the dash lights illuminate with the dimmer rotated CCW when the jumper is installed?

So, the park lights and clearance lights illuminate as soon as you jump power at the alternator.  Do the 'park' and 'clearance lights' include the tail lamps?  If you unplug the brown wire from the headlamp switch, do the park and clearance lights continue to illuminate? 

So I can track with you, what exactly are you referring to as 'clearance lights?'  Does the cab have roof lights?  Or, are you referring to the side marker lamps?