High-mount brake light question

[Yeret]

So, this weekend, I took off the "high-mount" lens from the back of the cab to replace the mini bulbs inside. Admittedly, I was kinda surprised to see that there were four in there.

The outer bulbs seemed to be intact, one of the inner bulbs behind the red lens was literally exploded, the other was burned. I replaced all 4 them and the "brake" bulbs work as they should (now making my truck probably the only 20+ year-old truck in the county in which these lights actually work, LOL), but the outer ones don't still seem to do anything.

I've tried to trigger the outer ones via every means I could think: turning on the headlight switch, putting a weight on the brake pedal, turning on the blinkers, putting the transmission into reverse (which did turn on the reverse lights in the taillight housings, of course), but still nothing on the little buggers up top.

My question is when are the outer lights in this assembly supposed to activate? The lens is clear in front of those ones, so I thought for sure they would turn on when the truck is in reverse, but they aren't doing anything.

 

[18CrewDually]

The outer bulbs are CARGO lights. Turn the wheel all the way up to CARGO to turn them on.

 

[Yeret]

Yep, you're right. And all this time I read "cargo dome" above the wheel as one word that simply referred to just the interior dome light.

Thanks for clearing that up!

 

[Chiefrider]

Not trying to hijack a thread, but it seems relevant, so...

Does anyone know of a source for a new OE type lens and gasket for the high mount brake light? My '97 looks pretty darn good, and I recently replaced the headlights, fog lamps and new rear lenses. The original high mount lens is pretty yellowed, just want to get this last detail- thanks!