Sorry for the delay, testing was not easy. It took 3 people but managed to get it done. The diagram below should give you an idea of what I have. All other lights in the rear are working as well, license plate lights, marker lamps, etc. Ground Junction block, wiring harnesses & Light fixtures & bulbs all New, including 3rd light above cab.
FYI, as far as throwing parts at it, I should let you know, I decided in Dec 2021, I wanted to do a complete "refresh" of all the lighting in & out of the truck, possibly the entire front clip.I've been stockpiling OEM parts hereuy & there since. A lot of little things were begining to go missing or getting worn, But nothing brake, turn, marker, fog or head light related have ever failed. Haven't ever had replace a bulb except a turn bulb once in the 4+years I've owned it. A lot of the things I've replace in the last mounth I've had on hand or were things already ordered, prior to this happing. Our money issue is recent, as I was holding off on getting more things for the truck when this accured. It's like someone "flipped a switched" & shut the brake lights off. Now I'm tryinto find That switch & turn it back on in the Dark. Lol
We managed to get a meter in to test Wht wire while connected to switch & pressing brk. This was 4.7v to 5.3v consitantly.
We then pressed the side of the brake switch as shown in pic below. Brake light came on, meter read (lowest)11.7v to 13.3v(highest). Difficut to do with 5 or 6 arms in a small space, but we managed to repeat about 3 times. So, like I said only seems to get power to switch when pressing on the side of it, If you can read my "chicken scratches" in pic. NOTE: now, Let me back up a little, before we replaced the switch harness, we put a meter to it. Probing the connector pin slot & the wht wire end dirrectly. Then we cut old harness connector out (Aprox 10") Before installing new 1, we tested wht wire, where we had just cut it. Almost exact volt readings as above. (Within 0.1 or 0.2) The new harnes was just shy of 9" long(8 7/8" I think) We soldered it in check & double check it. Again same voltage readings (not pushing brake) 4.7v to 5.3v consitantly. Pushing brake (BUT NOT touching the switch) 4.7v to 5.3v consitantly, And then pushing brk & Pushing in Slightly on the Switch (as seen in Pic). Brake light came on, meter read (lowest)11.7v to 13.3v(highest). The only voltage loss we're seeing is when you remove slight pressue from the side of the switch it self.
Anothering intresting thing, is the 1 ADJUSTABLE switch that we've tried, worked 180degrees opposite, meaning push w/ index finger away from you, while pushing brk & nothing. Move your finger to directly opposite side of switch & PULL slightly twards you then press brk, Bam, works till you release pressure. Look @ the switches side by side (naked eye) they look the same. Look closer & you'll notice the are opposite, as a "Right & Left" side door handle would.
We believe that whatever is going on is mechanical & in the interaction between the push rod & the switch itself. Everything I can find says this truck was (factory)equiped with Non- adjusting Brakes, but nothing else really specific, LIKE."If you were looking at "push rod or booster", is there some sort of "identifier" that you would(could) tell the difference between the Non-Adjusting & the Adjusting? Reason I ask is thus far, that's the 1st question we're asked when we've bought parts & we told them Non- Adjusting based off said data, never thinking anything of it. As of the end of today (430 CMT) we've contacted a least 7 different Chevy dealers service depts, and all of them conflicted w/ each other. Majorly. 1 told me, on Speaker for all to hear, that according to my VIN, it doesn't have Adjustable peddles & that the booster for Non- adjusting & adjusting peddles were physically different. That the Adjusting peddle booster could NOT be install on my truck w/o obvious (visually) modification. He then told me to go try to turn my push rod & I would see it doen't screw in or out it's stationary. He then said, the end of my push rod was round w/ a vinyal bushing in center of hole. So we hung up & went to check what he said. No obvious signs that booster was moddified or NOT original, infact still had the GM, QC name/date, plant & line (sticker) barely hanging on the bottom. We turned push rod 3 or 4 turns both clockwise & counter clockwise w relative ease & the end of rod that connects to brk peddle isn't round (see pic) nor does it have a bushing. So my calls the dealership back asks for that tech, then proceeds to tell him he needs to order a Brk switch, when asked for Vehicle Yr/make /model my buddy acts like he doesn't have it, but he has the VIN, tech takes the VIN, & within a min or 2 says "Adj or Non-Adj peddle, my buddy responds "ADJUSTABLE I think" within 30 sec, tech says "YEP It is, but I don't have any & wharehouse is out too, looks like I'll be able to get you 1 around the end of the Month. Thats how our info "gathering has been going & frankly, Dealerships have given most confusing info of all involved.
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Monday, January 9th, 2023 AT 4:03 PM
