Fog Lights Wiring and the Aux Connectors Question

[1FstGPa]

I am in the process of of ordering some parts to fab a simple wiring harness for my added fog lights. The plan is to use 14ga wiring, both + and -, to the aux connectors. #3 connector - upper right while looking at it - on the light gray connector shows as a ground. Will I need to run the negative side of the light socket to this connection or can I just ground to frame? My concern is making sure to take advantage of the auxiliary PDC on board relay for this light setup.

And while I have your attention...

Light gray #4 shows as a "Spare Circuit Pass Though." What exactly is that?

Thanks in advance!

 

[John Jensen]

Ground is ground. Ground where ever it's most convenient, just test your point to be sure it's grounded.
Suggest you do some searching on the pass through, etc. There's lots of info and diagrams. Basically it is a method to get the under hood switch circuit into the cab or to energize the rear of truck stubbed out wiring

 

[1FstGPa]

Ground is ground. Ground where ever it's most convenient, just test your point to be sure it's grounded.
Suggest you do some searching on the pass through, etc. There's lots of info and diagrams. Basically it is a method to get the under hood switch circuit into the cab or to energize the rear of truck stubbed out wiring

Thanks for that! I just wasn't sure if the auxiliary PDC was isolated or not due to the chip that is connected to it.
+
I never understood the reason for the second battery. I just thought it "might" be an outside chance for a second means for powering up some secondary circuitry or the need for added power? Hmmm?

I'm learning - I'm learning!

 

[John Jensen]

2nd battery for starting power on large (6.7) diesel engines