Chevy Tech's I need help!!!

[Jetdriver]

99 Chevy Tahoe. 4x4 4 door. The brake lights have stopped working except for the light bar above the rear door. I have tested the brake lead under the dash and have found it to be in working order. I have followed it to the molex in the firewall. I have tested all other wires that lead to the rear in a few spots under the vehicle. Each spot shows the same results of Running lights 13 volts, turn signals working, reverse working but no power for brake lights. Can someone please help me here, I usually figure these things out pretty quickly but this one is really giving me problems.
Thanks
Shawn :D

[Jetdriver]

All fuses have been checked and double checked. Again, the LED light bar above the rear window/tailgate comes on but the two lights on either side do not. So I can conclude that the switch is still good and has power. I have removed every fuse in the tahoe and made sure there wasnt something blown. I have also found the brake lead under the dash and Im getting 13 volts at that lead. Its somewhere between the firewall and the rear of the tahoe.

[Jetdriver]

Bulbs have been checked and even replaced. I have thought about running new wires if need be. I even tapped the brake lead under the dash and pluggen it into the brake lights in the back and they worked perfectly when I did this. I know its something in the harness, but what?

[wright on]

Twice this year I have had brake light problems and turnsignal problems. 1998 2 door tahoe with barn doors. I had to remove the bulbs clean the connection area out and keep rechecking. they eventuly start working. I know they make replacement bulb housing for those. I think I will replace mine next year

[H2OT TIMES]

Keep in mind, while your trouble shooting, that it is apparently in a part of the circuit that is common to both sides but not to the light above the doors or hatch or whatever.

[gnRacer98]

You may have shorted circuit boards. A common problem in that model year range. Do your turn signals work? I have a '98 pickup and have replace both taillight boards so far ($75 ea.) usually one side or the other, not both at the same time, look for discoloration around the bulb socket.
I was told the brake lamp tends to overheat them, excess load of trailer lights may contribute to the problem.

[502 JET]

Check the white wire from the brake light switch to the turn signal switch plug. Repair if necessary. This wire feeds power from the brake light switch through the turn signal switch. The wire may have broken off the switch or broke inside the colum. You may be able to repair the switch if you see a broken wire.
If your turn signals are working and no brake lights it usually means the turn signal switch is bad. Your brake light switch sends power through the turn signal switch. Your brake lights and turn signals share the same element in the bulb. So if the turn signals are working you know that the wires and bulbs are good.
The brake light switch is working that why you get the 3rd brake light only, it is fed directly from the switch and does not go through the turn signal switch.
It's not uncommon to loose only one function of the turn signal switch, requiring you to replace the entire switch.

[Oldsquirt]

Yep, what he said ^^^^^^^^^^^. :) Pretty standard for all the vehicles where the turn signals and brakes share a bulb filament.

[Jetdriver]

Thanks guys! Ill get a turn signal switch tomorrow and see what I can do.

[IMPATIENT 1]

if your high mount stoplamp is working than its definately a fuse, there's a stoplamp fuse under the hood in the fusebox on the driver's side fender. your stoplamp fuse is blown, the high mount has its own fused circuit independent of the rear stoplamps;)

[Jetdriver]

if your high mount stoplamp is working than its definately a fuse, there's a stoplamp fuse under the hood in the fusebox on the driver's side fender. your stoplamp fuse is blown, the high mount has its own fused circuit independent of the rear stoplamps;)
I checked that fuse as well and its still good. Im leaning towards the signal switch now. Tomorrow Ill know more

[YeLLowBoaT]

My guess is the wiring problem is very near the rear lights since the top light works.
The obvious question, have you checked the bulbs (or are these leds)?
actually, by federal law the 3rd tail light has to be run off a diffrent circit then the main brake lights.
If its not the fuse, then its your multi function swich/ relay.

[IMPATIENT 1]

I checked that fuse as well and its still good. Im leaning towards the signal switch now. Tomorrow Ill know more
RUN OUT TO YOUR TRUCK REAL QUIK AND STEP ON THE PEDAL, POP THE HAZARD SWITCH UP AND DOWN, SIDE TO SIDE ALITTLE AND TELL ME IF THEY START WORKING;)

[IMPATIENT 1]

if they do start working after you jack with the hazard button, that means the hazard contacts in the multifunction switch are melted, YOU DO NOT HAVE TO BUY THE 175-250 SWITCH, i have a cheap way to fix it right for under 30 bucks and you can do it yourself! let me know or pm me, and i'll get ya the gm p# you'll need to fix it, all dealerships stock the part but none tell ya you can fix the switches this way, they lose money doin my way:D

[JAY4SPEED]

if they do start working after you jack with the hazard button, that means the hazard contacts in the multifunction switch are melted, YOU DO NOT HAVE TO BUY THE 175-250 SWITCH, i have a cheap way to fix it right for under 30 bucks and you can do it yourself! let me know or pm me, and i'll get ya the gm p# you'll need to fix it, all dealerships stock the part but none tell ya you can fix the switches this way, they lose money doin my way:D
I remember that campain on S-10s ;)
Wasn't 99 a transitional year body style wise for the C/K platform. They had produced both old and new body styles in '99. Which body style are we dealing with here, the older square body or the newer rounded body for '99?
Jay

[JAY4SPEED]

Another option is to remove both tail lamp assemblies, get someone to press the brake pedal, probe from the yellow wire to ground on the left side and the green wire to ground on the right side. If they both have power, the turn / hazard switch is good and its most likely a bad socket board and bulbs. If you don't have power to the yellow and green wires with the brake pressed, then go after the turn / hazard switch. I can tell you the ratio I had replaced bad socket boards to turn signal switches was about 100 to 1.
Another thing that was real common was the aftermarket adapters that were placed in line with the harness for trailer wiring. Its that thing that you unplug the factory harness near the rear bumper and put in the "T" for the trailer harness. That adapter would go bad sometimes and cause lighting problems at the rear of the truck. If you have one, just unplug it and plug the factory harness back in and see if they work.
Jay

[IMPATIENT 1]

I remember that campain on S-10s ;)
Wasn't 99 a transitional year body style wise for the C/K platform. They had produced both old and new body styles in '99. Which body style are we dealing with here, the older square body or the newer rounded body for '99?
Jay
LOL, its nice to make some real time off shiat learned from gettin screwed by warranty labor huh:D if the customer is broke and i can tell, i give them the option. if i can tell the owners can afford to fix it right, i put a switch in;)
the switch worked for blazers, ck trucks and silverado's up till 02 i think.03 they switched to that flatter style button and switch i think, not sure but i do remember doin it to a couple 01 silverados.

[JAY4SPEED]

LOL, its nice to make some real time off shiat learned from gettin screwed by warranty labor huh:D if the customer is broke and i can tell, i give them the option. if i can tell the owners can afford to fix it right, i put a switch in;)
the switch worked for blazers, ck trucks and silverado's up till 02 i think.03 they switched to that flatter style button and switch i think, not sure but i do remember doin it to a couple 01 silverados.
I remember figuring out how to get the column covers off without pulling the steering wheel or airbag. Got that warranty time beat by a ton. If I remember correctly, the horn would sometimes go off when pulling that hazard switch out of the turn signal switch assy, that would scare the crap out of me.
Have you ever had the HVAC case out from a C6 Vette? I've got one right now that the "mode valve" had torn on thats kicking my ass. Its such a tight fit that I think that they start with the HVAC case on the assembly line and then start to build the car around it. Warranty time on it is 7 hours. I've worked on it on and off for 3 days now.:mad: I've cracked the case once trying to get it to squeeze in, SI2000 is way off with the service instructions, it just can't be done they way they have it in the manual.
Oh well, another day, another aggravation.
Jay

[creepingcharlie]

Another thing that was real common was the aftermarket adapters that were placed in line with the harness for trailer wiring. Its that thing that you unplug the factory harness near the rear bumper and put in the "T" for the trailer harness. That adapter would go bad sometimes and cause lighting problems at the rear of the truck. If you have one, just unplug it and plug the factory harness back in and see if they work.
Jay
funny you say that , I just solved a similar problem on a chevy truck not to long ago with one of those "T" in line.

[IMPATIENT 1]

I remember figuring out how to get the column covers off without pulling the steering wheel or airbag. Got that warranty time beat by a ton. If I remember correctly, the horn would sometimes go off when pulling that hazard switch out of the turn signal switch assy, that would scare the crap out of me.
Have you ever had the HVAC case out from a C6 Vette? I've got one right now that the "mode valve" had torn on thats kicking my ass. Its such a tight fit that I think that they start with the HVAC case on the assembly line and then start to build the car around it. Warranty time on it is 7 hours. I've worked on it on and off for 3 days now.:mad: I've cracked the case once trying to get it to squeeze in, SI2000 is way off with the service instructions, it just can't be done they way they have it in the manual.
Oh well, another day, another aggravation.
Jay
i;ve got all my vette certs but we sell maybe 2-3vettes a yr. and i hardly ever see any of them for service work, which is fine with me:D i'm 32 and not related to gumby anymore, my body won't deform the way its needed to work inside a vette,lol. i did have a convertible top issue last yr., me and a gm engineer spent 1wk on the damn thing , broke 3 trunk lids:D they finally bought it back and took it to the trainin center in dallas, never herd how it turned out.i'm lookin at a service manager position 30 miles south from me, time to tell people how to do it instead of doin it myself:D

[Jetdriver]

Sorry guys. Between the board going down and not having the time I havent fixed this just yet. Im going home in 15 minutes and start on it. Ill give all suggestions a try. Imp. ill hit you up with a pm if the hazards are the issue.
Thanks again
Shawn

[JAY4SPEED]

i;ve got all my vette certs but we sell maybe 2-3vettes a yr. and i hardly ever see any of them for service work, which is fine with me:D i'm 32 and not related to gumby anymore, my body won't deform the way its needed to work inside a vette,lol. i did have a convertible top issue last yr., me and a gm engineer spent 1wk on the damn thing , broke 3 trunk lids:D they finally bought it back and took it to the trainin center in dallas, never herd how it turned out.i'm lookin at a service manager position 30 miles south from me, time to tell people how to do it instead of doin it myself:D
Wow, I hope that managment position works out for you. Hell, you and I are the same age. I know the feeling of crawling under a dash and wondering if I'll be able to pull myself back out. We do a lot of Vettes here. I've worked on 4 this week alone including a sweet '08 Z06 yesterday. But, I'm the "vette guy" in my area so they tend to come to me for work. I imagine that you guys do a ton of diesel work, we hardly ever see diesels.
Jetdriver, what did you find out on the lights?
Jay

[IMPATIENT 1]

Wow, I hope that managment position works out for you. Hell, you and I are the same age. I know the feeling of crawling under a dash and wondering if I'll be able to pull myself back out. We do a lot of Vettes here. I've worked on 4 this week alone including a sweet '08 Z06 yesterday. But, I'm the "vette guy" in my area so they tend to come to me for work. I imagine that you guys do a ton of diesel work, we hardly ever see diesels.
Jetdriver, what did you find out on the lights?
Jay
it was the em switch, he called me yesterday and got the p# for the campaign switch kit.
yep, i'm the deisel/electrical/driveability guy for my area,lol. i work on at least 1 duramax, powerstroke or ole 6.5l a day. don't mind workin on them i just can't stand the smell of the fuel though, it turns my stomach:(

[Jetdriver]

it was the em switch, he called me yesterday and got the p# for the campaign switch kit.
yep, i'm the deisel/electrical/driveability guy for my area,lol. i work on at least 1 duramax, powerstroke or ole 6.5l a day. don't mind workin on them i just can't stand the smell of the fuel though, it turns my stomach:(
Thanks yet again Tom!!!!!!!!!!!!! I had the wife grab the part yesterday and switched it out within a few minutes. Brake lights work and the hazards do as well. Thank you for the help you saved my butt big time.
Shawn :D

[IMPATIENT 1]

Thanks yet again Tom!!!!!!!!!!!!! I had the wife grab the part yesterday and switched it out within a few minutes. Brake lights work and the hazards do as well. Thank you for the help you saved my butt big time.
Shawn :D
no prob man, glad to help. pm me if ya ever need help again on the truck, i know every circuit in them;)

[Jetdriver]

no prob man, glad to help. pm me if ya ever need help again on the truck, i know every circuit in them;)
Will most definitly do just that! :D