Pay close attention to the harness connector after you unhook from the old brake light connector. Sometimes wire memory happens and it has some pull there and the wire will suck back in there.
Third BRAKE light stopped working
- Thread starter jhilario72
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jhilario72
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Not sure, I never checked the cruise control. Thanks for the suggestion
Brake light switch should be fine since he already said the other brakes lights are working properly.
I would think the first thing to check is the CHMSL fuse for voltage on both sides, as well as good pin fitment. Then see if you have voltage at the high mount stop lamp connector when the brake pedal is depressed.
If there's no voltage at the CHMSL connector, look under the truck behind the right rear wheel for the lighting connector plate. I know, it's not the best place for wiring connections (dirt courtesy of Kebler Pass, Colorado):
If I recall correctly the taillight circuits run through that, but I can't tell you which one would be for the high mount lamp. Carefully remove the connectors and check for cleanliness and pin fitment. Maybe someone has a wiring diagram that would show which wires are which.
If there's no voltage at the CHMSL connector, look under the truck behind the right rear wheel for the lighting connector plate. I know, it's not the best place for wiring connections (dirt courtesy of Kebler Pass, Colorado):
If I recall correctly the taillight circuits run through that, but I can't tell you which one would be for the high mount lamp. Carefully remove the connectors and check for cleanliness and pin fitment. Maybe someone has a wiring diagram that would show which wires are which.
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99% chance it is the light burnt out, a replacement is like $20 off of amazon all day long. those brake lights fail like a fat man running a marathon on the gmt800's
Op already stated he has voltage there.
Where do you see that? I see two posts by the OP and neither one indicates the results of any testing.
I double checked too. I don't see where the OP says there is voltage there. He says the other brake lights work though. Don't "Mess with Fless".
in the last 23 years my average life for that 3rd brake light has been maybe 3 years and every one I pulled from junk yard trying to save $5 was bad, except for maybe 1
just had to replace the one on the 05 and it was newly replaced about 3 years ago.
people usually don't even notice it unless someone mentions hey you have brake light out, I occasionaly back up to a glass window at night and check my lights in the mirror.
they either burn out entirely, or get very dim, or several of the led's will fail and/or get dim at the same time.
really the only other thing that happens is the rubber seal can deform allowing water and dirt in the harness socket area causing some corrosion.
super easy to just throw a meter on the 2 socket pins and have someone hit the brake pedal to verify operation.
just had to replace the one on the 05 and it was newly replaced about 3 years ago.
people usually don't even notice it unless someone mentions hey you have brake light out, I occasionaly back up to a glass window at night and check my lights in the mirror.
they either burn out entirely, or get very dim, or several of the led's will fail and/or get dim at the same time.
really the only other thing that happens is the rubber seal can deform allowing water and dirt in the harness socket area causing some corrosion.
super easy to just throw a meter on the 2 socket pins and have someone hit the brake pedal to verify operation.
jhilario72
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Thanks for all the great info. I thought my 3rd brake light was completely out, but upon closer inspection, it is indeed very dim. I ordered a new LED one from Amazon. Hope to get it this weekend and install it. Let you all know! Happy Holidays!
Joe
Joe
