Need some third brake light info

[Mike-M]

My truck failed state inspection the other, one of the things on the list was that my 3rd brake light doesnt work. To be honest I didnt even think I had one on a truck this old, but the internet tells me that anything from 1986 or later has it by law. So I spent sunday afternoon tracing wiring, and I cant find anything from the brake light circuit besides the wire to the back of the truck. Today I received the wiring diagram, and I spent a couple hours going through it, and I dont see any mention of the third light at all in there.

Im on a wild goose chase here, arent I?

 

[racin460]

my 90 don't have one just a cargo light if there is a red lens on there it should work for inspection. my suggestion is to just get a cargo light and not the red then they cant fail it.

 

[gandalf]

I believe they're mistaken. I think that is true for CARS, for passenger vehicles, but not trucks. My wife's '87 Buick has the 3rd brake light. My '89 Isuzu Trooper does not. The Trooper is, technically, a truck, by import designation, though the state of California registers it as a car.

You might ask them to verify their facts.

 

[Sycostang67]

I believe they're mistaken. I think that is true for CARS, for passenger vehicles, but not trucks. My wife's '87 Buick has the 3rd brake light. My '89 Isuzu Trooper does not. The Trooper is, technically, a truck, by import designation, though the state of California registers it as a car.

You might ask them to verify their facts.

That is correct, I don't believe trucks were required to have them until the mid 90's. My 93 does not have a third brake light, but in 1995 I know they did. It is possible to add the third brake light from the later OBS trucks. You just have to enlarge the opening a bit to fit the larger housing and run the extra wire to your brake light switch.

 

[Leeland]

I'd have to look at my harness I got laying around for converting by back doors to electric but pretty sure its part of the cabin harness. Haven't looked into the light fitment yet, was wondering about if there was a size difference, glad that got brought up.