CHMSL = center high mounted stop light
It's mounted externally, on the roof side of the hatchback glass. This was the first and only year Z28's and IROC-Z's had this unique feature.
I'm perplexed because this item seems to appear or disappear, dependant upon what State the car was sold in. I've seen (allegedly authentic) cars without it!
What is reality, about this brake light thingy? Are '86 Camaros without a CHMSL counterfeit? Don't DOT rules apply consistently, throughout the contiguous States?
Thanx, Smiteman