No brake lights?

Welcome to the forum, I'd check the feed to and from the brake switch. Orange wire is hot all the time. White wire goes hot when you activate the brake switch. The high-mount lite is wired differently than the others. Here is the wiring diagrams so you can see how it works with a guide to help you check for power.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester


Check out the diagrams (Below). Please let us know what you find. We are interested to see what it is.

[quote:c891175855="jdl123"]Welcome to the forum, I'd check the feed to and from the brake switch. Orange wire is hot all the time. White wire goes hot when you activate the brake switch. The high-mount lite is wired differently than the others.[/quote:c891175855]

thanks. Are there any helpful hints or advice on replacing the brake switch. I have tried to wedge myself under there a month or two ago and it seems impossible to get that thing off or even get to it. Do i need to find a 10 year old to do the work?
My hands seem too big. haha

I found this, don't know if it will help? I don't like to work under dashes.

OK. Thanks for the help so far.
I replaced the brake light switch. The brake lights still dont work. I checked all the fuses and they are all in good shape. I checked under the hood and the fuse panel inside the truck.
I noticed that the people before my mom had the truck extended the plug for a trailer. It seems that all the connectors are fine on there. Im getting a test light from a friend tomorrow to see if i have power to the trailer harness.
Is there any more suggestions as to what it could be?
Im almost to the point to where i dont want to mess with it period. Im trying to save her some money though.
Remember all 3 brake lights dont work.

Hi, in the earlier post, I gave you the wiring colors to check, are they hot???

I dont have a test light. Im getting one from a buddy at work tonight. We have about 90% chance of rain tomorrow so it looks like its gonna be Saturday when i get around to it because of the weather.

Ok guys. I got a test light and im getting power to the switch. I cant access the white wire while it is plugged up because GM wanted 6 year old children to only reach that area i guess. How can i determine if i have power coming out of the switch if i cant get to the white wire out of the switch. Is it near another that is more accessable.

Hi, unplug the connector from the switch, use a jumper wire from the orange wire to white wire, see if brake lites come on. I don't like to work under dashes, either.

alright.. i will try that tomorrow.
Does that white wire go to the turning signal switch? If so, would it be easier to gain access to that area and try the white wire up there?

Does the high-mount brake lite work? That brake lite isn't wired through the turn switch, the lower brake lights are. When working around steering column, you disarm airbag, where applicable.

There may be a multiwire connector under dash, close to steering column. For the circuits going to and from the steering column. You may be able to check wiring circuits, there. The wiring colors on the picture may be hard to read?

Ok i took the jumper wire and jumped from the orange one to the white and still no brake lights. I had a maintenance guy from my moms apt complex helping me and he is stumped also.
Still getting power to the orange one with the test light. No brake lights while jumping orange to white.

The 3rd (upper) brake light isnt working either. None of them are working.
Should i see if im even getting power to the wiring harness for trailers. Would that help any?

Yeah, you can look for power at the trailer connection. I'm going to track the splices on the brake circuit.

You see splice S220 in the picture, I'd have to track the white wire and check for voltage.

I went to a tech school in 2000 for automotive technology and when we got to the part that we are at now, is when i dropped out. HAHAHA. I dont have a whole lot of patience for stuff like this. The other things that i have done so far are ok as far as the brake switch and checking to see if i have power and stuff like that but now it gets to the hard part to me.
I actually bought the tahoe from my mother yesterday so im going to pick it up in a little while so it will be at my house shortly so i can just go back and forth inside and out to check things. Its aggrivating when i have to track her down and go over there.

Ok i just turned the headlights on and checked the harness. I have power on the brown wire and that is it. I didnt turn on turning signals or anything like that. I checked all of them but the brown wire was the only one hot with only the headlights on.

Can you check the bulb on the high-mount brake lite? Is it ok? Unplug the bulb and use a testlite in the bulb socket, brake activated, any voltage? If not your need to locate splice S220.

Looks like the upper 3rd light has a bunch of LEDs instead of a single bulb set up. I took the two screws out but had no luck removing the light or cover.
I talked to a local mechanic that specializes in these type trucks and SUVs and he is saying its the multi-switch also.
Ive got one ordered for 109.00 shipped. Im gonna see how this goes. He said something about the whole steering wheel had to be removed to replace it because of a screw that it holding it in there.
Any tips on an easy removal of the steering wheel.

Can you get at the wiring circuit for the high-mount brake lite, to see if there is voltage when the brake switch is activated. The voltage circuit for the high-mount brake lite, isn't wired through the multifunction switch.

If your going to remove the steering wheel, disarm the airbag first, where applicable. Get a steering wheel puller. goodluck

Alright guys. ** update**

I went ahead and got another multi function switch hoping that the third brake light was just blown and it would resolve the problem with the lower 2.
NOPE... that wasnt it. Still no brake lights.

So i have :
Checked all fuses
Replaced brake switch
Jumped a wire from the orange to the white and no brake lights
Put the multifunction switch on

Any suggestions.
Where do the wires run after the multi switch?
Are the inside the frame of the vehicle or just against the outside of the chassis.

WOW this is fun.
My hands look like i defended myself from a knife attack. GM wanted 6 year olds to work under the dash i guess.

Did you check the circuits at the multifunction switch?
Check multiwire connector under dash, close to steering column. That connector should be for circuits going to and from the steering column. With the brake applied, the dark green wire and yellow wire, both should be hot, if they are not hot, the problem is before the test-point, not after.

[quote:84f47ce66b="jdl123"]Did you check the circuits at the multifunction switch?
Check multiwire connector under dash, close to steering column. That connector should be for circuits going to and from the steering column. With the brake applied, the dark green wire and yellow wire, both should be hot, if they are not hot, the problem is before the test-point, not after.[/quote:84f47ce66b]

Ok i will try that tomorrow.
So the same big connector that the multi switch plugs came out of is the one that you are talking about that is behind the knee balaster?
Is it the green and yellow wire on the firewall side or seat side of the big connector?
I will take all that mess back off tomorrow. We are still driving it so i had to put it all back together.

Those wiring colors are two separate wires, under the dash, those wires are brake lite feed from the multifunction switch, for left and right brake lite at the rear. The high-mount brake lite is not wired through the multifunction switch. I didn't think the problem was in the multifunction switch, but, we can check circuits anyway.

I was talking with my dad on the phone and he has been trying to help out with this also.
We were trying to figure out why no brake lights but have flashers.

The emergency flashers are the brake lights correct? Im not sure what would happen if i applied the brakes while the flashers are going. I havnt tried that yet.
Since the brake lights dont work but flashers do then the problem is definatly in the dash somewhere right? Am i kinda on the right track here. haha.
Its 4:45am now so i will try to check some things when i wake up today if i have time.

Thanks for all the help so far.

I believe the problem is the feed to the multifunction switch from the brake lite switch. The feed from the brake lamp switch to the multifunction switch and the feed from the flasher to the multifunction switch are two different feed circuits. Have fun.

I checked the green and yellow wire at the connector. No power to them when the brake is pressed in.

I still have cruise control and it will cut off like it supposed to when i press the brake.

Check the white wire going to the connector for voltage with the brake switch activated. If there is more than one white wire, I don't know which one?

If no voltage on the proper white wire, brake activated, you'll have to backtrack the white wire. You could take the connector loose at both ends, make sure it is the correct circuit, do an ohms test, check for continuity, no continuity, there is an open circuit. All repair info says to disarm airbag, where applicable, when working under the dash.

I've done some more digging today and i traced the white wire from the brake switch to a connector just above the steering shaft. I think this will cause it to mess up everytime. Im going to get a connector but i feel quite confident this is fixed. Thanks for all the help.

Well, I hope you got it going your way. goodluck

It worked., Thanks for the help. im back on the road again

well i spoke too soon. Ive ran into another issue.
When the headlights are in the off position all of the brake lights work fine. When the headlight switch is in the parking light or "on" position then only the upper and passenger side brake light works. Also the left blinker blinks really fast when the parking or headlights are on. Other wise the left and right blinker blinks fine.
When the headlights are on and i press the brake the whole drivers side tail light assembly goes out completely.

The left blinker issue happened before i found the broke wire yesterday. This , i guess, was an ongoing problem that my mom didnt tell me about.
what kind of issue am i looking at here.

Sorry for the late come-back. Having trouble with e-mail. Yesterday, I didn't have any, today, I have 13 dating back to Saturday.

About your question, In an earlier post, I gave you the wiring colors to check at the steering column connector, for feed, to left and right brake lites. Check those feed wires for voltage when the problem is ongoing.

I had an issue a while back.. with my 99 Tahoe

No brake lights one day..
Did the wires thing. Noticed the light switch also..
Left will flash fast,. right wont.. or something weird..

I figured out the issue by accident.
I hope this helps.. Im sure it will.

Step by step ~
Start the truck / Turn on lights to full.
Bring the steering wheel down using the
tilt, Then hit the left signal switch to stay down.
Then press down on the Hazard button/Switch.
Then turn if back off. See if there was any change.
PRESS HARD ON IT on the DOWN and jiggle on it and watch for it.

I had to break mine out to fix my issue..
I dont suggest to do this. But i had too. lol

" Sometimes you have to break something to fix it. " ~ Me

Hi there ive got a problem ive replaced the brake switch 3 times thinking they might of been bad,allso replaced the brake fuse, but still dont have any brake lights,they have allways worked till now what could i check or do to fix this problem. thanks Jeff

Ok you have one of two problems here. Either the turn signal switch is bad or you have bad circuit boards in your tail lights. As long as there is not wiring problems or no one added a trailer light connector and did it wrong or something. Here is the taillight connector plate. If I was going to replace them to find out I would do one first as most parts stores will not take back electrical parts once pluged in.

Hi you responded to me but i dont have turn signal problems.i have no brake lights ive replaced my brake light switch like 3 times just in case they were bad. An replaced the brake fuse allso but no brake lights still.what to check thanks jeff

Yes excatly I know what your problem is now please check the circuit boards (pictured in the previous response) in the taillights and still it could be a turn switch. See the turn signal switch is where all the power goes for the brake lights. The power goes through the turn switch then to the brake light light switch that is how the turn switch is able to interupt the brake light to make it blink when you use the turn signals. I hope this helps explain how it works. Get back to me as to what you find. To check the circuit board you may need an ohm meter if you can't find obvious signs of a short or burn on the board.

Oh yea one thing to check first do you have power going to the brake light switch?

Thanks for your addvice,you were wright someone addeda trailer hitch an lights, when they did the just about cut through 2 wires in the harness, just enough so over time they came apart to the point were they were just barely makeing contact. i fix the 2 wires an the brakes work great thanks so much for your help. i will letting any one know about your site if they have any problems. thanks again, Jeff

I hasve check fuses, replaced brake light switch, bulbs, bulb panel,. looking for brake relay, not in underhood / fuse relay box, any ideas? where is multi-function relay/switch? no brake lights, not even LCD on top, will turn signal switch have anything to do with this problem?

Great glad to hear they are working again. Thanks for the support. It all of you that keep us going. Again thanks and have a great weekend.