Hi Jeff,
This may help. If you can post more pics it helps use see more of what you are talking about.
In our FILES section, under "Sunline Electrical, Lighting & Charging Systems," there are four KIB Enterprises files. One at the top of the page and three down below. You can download them, and they have a wiring diagram for the red cube, which is the resistor pack. Here is a hot link direct to that subfolder.
https://www.sunlineclub.com/forums/downloads.php?do=cat&id=14
I cannot tell if your resistor pack is damaged. If you need a new one, see here for one place that sells them.
https://www.amazon.com/KIB-K101-Replacement-Tank-Harness/dp/B007HRRBTM?th=1
I do not know what the KIB tank panel is in your camper, so take a pic and post. This file shows just the one red rocker switch for the pump, but it shows the tank sensor wire color call out, which is the same regardless of how many switches are on your tank panel.
https://www.sunlineclub.com/forums/downloads.php?do=file&id=412
The White wire is the DC neg, ground wire. It should go to the lowest tank sensor pin in the tank. It does not go to the red resistor pack. From the lowest tank sensor, it goes to DC negative in the camper. There is not enough picture to show where the pump negative wire is as we cannot see the pump itself.
From the red resistor pack, the red wire coming out of the red cube is the signal wire that goes up to the tank panel with all the lights. I cannot tell you what color Sunline used for the signal wire, but I can tell you how to figure it out.
Go to the tank monitor. These pics are from my camper, which has two red rocker switches. Yours may be similar, but it should come apart in a similar way.
On the side of the panel is a tab; use a small straight-blade screwdriver and twist/pop the cover loose
When you get the light panel off, there is a circuit board plug on it
See the wire colors on the plug,
Your goal is to find what color wire Sunline used to run from the tank panel down to the fresh tank. If you undo the white flange ring on the wall, gently remove the wire nest, and you should find wire nuts showing the colors of the wire they used.
According to the KIB wiring diagram, the blue wire on the PC board connector is for the fresh tank. See what color wire Sunline used to run that KIB blue down to the fresh tank and look for it at the tank. That color wire will connect to the red wire on the resistor pack.
The KIB brown is for the black tank
The KIB grey, is for the grey tank.
Be careful; those little wires can unplug from the red PC board connector; they are just pushed in, and the connection pin cuts the wire insulation to make contact.
If you cannot back into the color of the fresh tank wire, go under the camper and find the black and grey tank colors and red resistor pack wire colors, then compare them to what is up at the tank panel. That eliminates two of the three colors.
If your water pump switch is on that KIB tank panel, see what color Sunline used to wire the pump switch; that wire color should show up at the pump.
If I can see the wires coming out of the water pump, I can figure out which is DC neg and which is DC hot. You can also try it from these words. DC hot at the pump goes into the square cube at the end of the water pump. The square cube is a pressure switch, and a red wire comes out of the motor and goes to the pressure switch. Then, a second red wire comes out of the pressure switch, which is the DC hot wire from the tank panel that runs the pump. Sunline picked its own color for the hot wire; it would wire nut onto the pump red wire pigtail.
A DC neg ground wire is coming out of the motor; I don't know what color it is on your motor.
Somewhere at the pump and tank sensor area is most likely a white wire that is the DC neg, ground wire for both the pump and the fresh tank. I cannot see this in your pictures. Sunline has used white stranded wire as DC negative in many cases. I don't know if white or DC neg dates back to your mode year, though.
I hope this helps; if you can't sort it out from this, post more pics, and we can see it better to help better.
John