Of course, I suppose that will help.
Mine is an LMTV1079 with the 3126 engine. With a whopping 5400 miles on her. Almost no modifications to her prior to my purchase with exception of a poorly done cab insulation/sound deadening job. Currently working on that.
As for what I'm looking to run from the switch panel, at the moment, accessory lights, GMRS radio, and a couple of interior lights. I've only had the truck for 10 days now so I'm wanting to keep options available for expansion down the road.
I'm not new to build outs and dealing with a standard civilian 12V setup. However, green around the gills with not only a 12v AND 24v but the wiring setup that the military has in these trucks. As you may know, it's overwhelming once you get into the guts of the truck.
Also, at 46 yo I'm new to these types of forums and tried to do my due diligence before posting this first post so as to not ask a redundant question. I didn't have any luck finding anything on here and YouTube wasn't any help.
Thanks again!
Very good. We all are dealing with replacing old rubber and cracking electrical, items previous owners did that may not help, and what we wish our vehicles to become.
The units with the CAT 3126b typically fall into two groups: before 18,550 and after. Though there are some outliers.
In most the A1 units (someone will correct me) the power distribution panel (PDP) has four large bolts: a 24v feed to X1 and a separate 12v feed to X3 from the batteries. Looking at the bolts from left to right in the photo below: 24VOLTIGN (X2 in the schematic) fed from 24VOLTBAT (X1); 12VOLTIGN (X4) fed from 12VOLTBAT (X3) We have a 18,550+ A1 here is a photo of our PDP, yours may be different:
We make sure the manual disconnect is switched off before working on the PDP.
There are four large phillps screws under the windshield and four high on the front of the passenger kick plate (not the screws on the PDP panel itself) that allow you to remove the whole PDP and access all the wiring and battery connections under the PDP. It sounds like you may only need about 12v at 10 - 15 amps. You may want to use an unused fuse in your unit (the schematics help greatly with this) or a new fused connection you add directly to one of the X1-4 bolts. I would not use your switching panel directly without a fused link between it and the panel.
I like drawing out the schematic of what we are planning before making changes for a few reasons: 1– I can post it here for suggestions; 2– it makes me think about how much amperage I need to power all I have in mind; 3– it forces me to document what I have done so that 3-5 years from now I can retrace my steps.
@TechnoWeenie made a good suggestion for the type of devices you mentioned wishing to add regarding the delay. Adding the separate batteries may also be a good idea, though the loads you are adding now may not be enough to justify? Adding loads to your box likely changes everything.
Good luck, it is a fun journey working on our trucks–
