Courtesy Lights and Assumptions

[MysticRob]

Okay, some questions will follow in this thread that I'm trying to answer, but want to verify some assumptions first.

I'm restoring my 88 and the rear cargo light wiring is a mess, so I'm not quite sure how the courtesy lights should function. In other words, I don't know what right looks like.

#1: Are the courtesy lights supposed to come on when the tailgate is lowered?

#2: Does the cargo light switch turn all courtesy lights off, or just the cargo area light?

[Driftwood]

#1 - No
#2 - Just the cargo light

At least that's how they worked on my 84, 85, and 79.

Okay, some questions will follow in this thread that I'm trying to answer, but want to verify some assumptions first.

I'm restoring my 88 and the rear cargo light wiring is a mess, so I'm not quite sure how the courtesy lights should function. In other words, I don't know what right looks like.

#1: Are the courtesy lights supposed to come on when the tailgate is lowered?

#2: Does the cargo light switch turn all courtesy lights off, or just the cargo area light?

[MysticRob]

Okay, so next question, assuming my 88 and all 3 of your other GWs are identical, does one of the wires from the cargo light screw into the roof support cross beam for ground?

I ask because I'm trying to figure out why there are 3 wires coming out of the dome light.

Another question: Is there a way, using the cargo light switch, that you can turn on ONLY the cargo light, and no other light??
I guess what I'm trying to figure out is WHAT exactly happens when that darn switch is turned to OFF or ON.
What happens with whatever lights (dome, cargo, or otherwise) when it's switched to OFF?
What happens with whatever lights when it's switched to ON?
What other precursors have to occur for the switch to work? Do doors being opened and/or closed affect the operation of that switch?

I really need to understand the functionality of the switch, AND how things should be wired back there to make that functionality work.

[wiley-moeracing]

I do not have one to look at so here it goes, 3 wires coming off this switch, 1 would be ground and the 2 signal wires(power), 1 would have signal(power all the time, 2nd would be signal(power) when doors and or dimmer/interior switch is activated. The on off switch should have power all the time so when it is turned on while in the back area you can turn the switch on/off without the doors or dimmer/interior lift activated. Now if there is 3 wires off the light but it grounds through a mounting screw then the 3rd wire may be activated by the tailgate being lowered.

[MysticRob]

Wait, so one poster says the tailgate raising and lowering has nothing to do with the cargo/courtesy lights coming on or going off, and one poster says it does.

Which is the case then? I doubt the tailgate has anything to do with it based on the wiring I've seen in there. Other than the safety switch back there, which doesn't look like it's tied into anything else like courtesy lights, there's no way for the vehicle to know whether the tailgate is up or down.

See, I'm trying to figure out the proper operation of that cargo light, and of the cargo light switch, so I can better understand how to wire them to do what they should be doing.

Thus far I've gotten the 2 under-dash lights and center/map light to come on/go off properly when the doors are open/closed (and with the IP dimmer switch), but without knowing how the cargo switch and light are supposed to operate I can't really tell how to wire those 2 things that were unfortunately already hacked up and disconnected when I bought the GW.

Keep the posts coming, the more info we get here the better our chances of getting it right.

[MysticRob]

Okay, I was able to figure it out!

I used the following pic from the following site, and figured it out:

https://www.fourwheeltrends.com/wp-content/uploads/2016/07/img_4760-e1468090844942.jpg

That allowed me to figure out the black/brown pair coming back from the front dome/map light area wires into the same black/brown pair on the cargo light. Then the 2nd black wire (aka the 3rd wire on the light, which is actually just the same black wire running thru the cargo light) then wires into the cargo switch's black wire. From there the switch's brown lead actually gets wired to ground. So all blacks are wired to black, and browns except for the swtich are wired to brown.

This entire run now has this effect:
1. Any door opening now turns on ALL of the courtesy lights (not maps lights though) including the cargo light.
2. The cargo switch in the ON position now turns ON ALL of the courtesy lights (not maps lights though) including the cargo light even when all the doors are closed.
2. The cargo switch in the OFF position now turns OFF ALL of the courtesy lights including the cargo light but only when all the doors are closed.
3. Tailgate has nothing to do with the operation of the lights.

[wiley-moeracing]

A test light would have worked also, as I said I do not have one in front of me so going off of what you posted.