No brake lights?

Tiny
UTHNKUNOME27
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  • 1998 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
Has blown a few taillights in the past. I replaced the passenger side circuit board in the taillight housing. She has owned the truck for over a year and really had no problems with it what so ever. About a month or two ago she had no brake lights. All turning signals work, tail lights work but just no brake lights.
Should I go ahead and replace the left side circuit board on there? The third brake light dont work either up top.

Is the right side tied into the left side. So if the left side went out it would kill the other 2?

The brake lights started back working about a month or two ago for a few days and they quit again.

There has been no aftermarket trailer light put on there to my knowledge. At least not since she has had it.

Any help would be greatly appreciated.
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Friday, December 11th, 2009 AT 3:00 PM

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Tiny
JDL
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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.
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Friday, December 11th, 2009 AT 3:09 PM
Tiny
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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
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Tuesday, December 15th, 2009 AT 3:56 PM
Tiny
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I found this, don't know if it will help? I don't like to work under dashes.


https://www.2carpros.com/forum/automotive_pictures/170934_brake_light_swich_1.jpg

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Wednesday, December 16th, 2009 AT 9:58 AM
Tiny
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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.
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Thursday, December 17th, 2009 AT 3:32 PM
Tiny
JDL
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Hi, in the earlier post, I gave you the wiring colors to check, are they hot?
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Thursday, December 17th, 2009 AT 4:26 PM
Tiny
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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.
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Thursday, December 17th, 2009 AT 5:32 PM
Tiny
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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.
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Monday, December 28th, 2009 AT 2:20 PM
Tiny
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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.
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Monday, December 28th, 2009 AT 3:42 PM
Tiny
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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?
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Monday, December 28th, 2009 AT 4:16 PM
Tiny
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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?
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Tuesday, December 29th, 2009 AT 10:21 AM
Tiny
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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?
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Tuesday, December 29th, 2009 AT 3:28 PM
Tiny
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Yeah, you can look for power at the trailer connection. I'm going to track the splices on the brake circuit.
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Tuesday, December 29th, 2009 AT 3:35 PM
Tiny
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You see splice S220 in the picture, I'd have to track the white wire and check for voltage.


https://www.2carpros.com/forum/automotive_pictures/170934_tahoe_s220_1.jpg

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Tuesday, December 29th, 2009 AT 3:52 PM
Tiny
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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.
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Tuesday, December 29th, 2009 AT 4:03 PM
Tiny
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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.
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Tuesday, December 29th, 2009 AT 5:26 PM
Tiny
JDL
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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.
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Wednesday, December 30th, 2009 AT 9:15 AM
Tiny
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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.
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Wednesday, December 30th, 2009 AT 5:15 PM
Tiny
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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
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Thursday, December 31st, 2009 AT 9:07 AM
Tiny
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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.
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Monday, January 11th, 2010 AT 4:29 PM
Tiny
JDL
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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.
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Tuesday, January 12th, 2010 AT 9:21 AM

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