Third Brake Light Not Working

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Tahoecar

TYF Newbie
Joined
Jun 20, 2010
Posts
8
Reaction score
0
99 Tahoe w/towing package. Third brake light stopped functioning. I replaced the light, but the problem seems to be that there is no voltage coming to the light. Checked IP fuse #1 = okay. I assume there is a short, but not sure where to start looking?

I've read some posts that suggest that the hot line (w) for the light may come from the towing lighting harness? Others mention that the voltage comes through the brake switch (over steering column).

This light seems to be a fairly common problem with Tahoes. Any experience out there? Thanks.
 

Crispy

Full Access Member
Joined
Apr 9, 2010
Posts
72
Reaction score
3
Location
Slate Belt, PA
Brake lights stopped working on my 01 Firebird, first the left then the right. Turn signals and parking lamps still worked. Turned out being the turn signal switch. Verify voltage at the brake light. If you have a power probe hit it with 12v and verify light operation, if not, use some wire from a 12v source as a jumper. Im willing to be its the turn signal switch. If it is, and the process is the same as the Bird, your air bag and steering wheel will have to come off. You may need a steering wheel puller,
http://www.northerntool.com/shop/to...s&cm_ite=205108?ci_src=14110944&ci_sku=205108
You can rent one at Autozone or parts chain like it.
 
OP
OP
T

Tahoecar

TYF Newbie
Joined
Jun 20, 2010
Posts
8
Reaction score
0
Brake Light Switch

Crispy, thanks for you insights. I checked my workshop schematic and couldn't find a clear connection with turn signal, but won't rule it out. I have found some discussions that suggest that there may be a connection with trailer hitch wiring; I hear it is a dealer-installed option?

Wonder if you, or anyone out there, has fixed a third brake light problem by replacing the brake light switch (located over the steering column)?
 

Crispy

Full Access Member
Joined
Apr 9, 2010
Posts
72
Reaction score
3
Location
Slate Belt, PA
I have a diagram here, looks like the brake light switch isnt gonna be at fault, otherwise all of your brake lights would be out.

Sorry the pics so centralized, im on my netbook with a small resolution. It looks to me tho that the circuit does tie into the turn signal switch. The trailer harness was a factory option, using yellow and green for stop/turn function, just like the factory harness. Those are wires to test if you believe thats involved.

Hopefully these help.
http://i18.photobucket.com/albums/b103/crills/tahoeschem1.png
http://i18.photobucket.com/albums/b103/crills/tahoeschem2.png
 
OP
OP
T

Tahoecar

TYF Newbie
Joined
Jun 20, 2010
Posts
8
Reaction score
0
Thanks for the diagrams Crispy! Helped me rule out testing some wiring locations. And, I believe you are correct about the wiring at the turn signal switch.

Ready for this? I literally tripped over the fix. On my Tahoe, the "convenience center" is located under the left side of the dash panel, near where I rest my left foot when driving. I noticed that all of the wires, to include the white wire for the brake light, were mashed down toward the floor...presumably, from me bracing myself as I repeatedly bring a 6,800 lb. mass of metal to a successful stop. :)

I simply raised the wires from the floor to ensure good terminal connections, and bingo - the high mounted third brake light began working!!! Thanks again for addressing my questions/comments.
 

Sabre

TYF Newbie
Joined
Aug 9, 2010
Posts
2
Reaction score
0
Crispy,
Do you by any chance have the diagram for a 96 Yukon 5.7L gas engine brake light switch? I lost both of my brake lights and hazard lights, but have my turn signals and tail lights. I'm at a loss here unless the switch itself is bad. I thought I'd look at the wiring diagram, find which wire goes where (6 of them A-F, White, Orange, Purple, Brown, Green, Blue (at the switch)).

I thought I'd jump them manually with a piece of wire to verify the switch or to see if I have a short somewhere. I'd really appreciate your help here sir.
 

96tahoe2door

TYF Newbie
Joined
Feb 23, 2022
Posts
1
Reaction score
0
Thanks for the diagrams Crispy! Helped me rule out testing some wiring locations. And, I believe you are correct about the wiring at the turn signal switch.

Ready for this? I literally tripped over the fix. On my Tahoe, the "convenience center" is located under the left side of the dash panel, near where I rest my left foot when driving. I noticed that all of the wires, to include the white wire for the brake light, were mashed down toward the floor...presumably, from me bracing myself as I repeatedly bring a 6,800 lb. mass of metal to a successful stop. :)

I simply raised the wires from the floor to ensure good terminal connections, and bingo - the high mounted third brake light began working!!! Thanks again for addressing my questions/comments.
Do you remember what colors the wires going into the conveince center where for the 3rd brakelight or do you have a picture of the connection
 

Forum statistics

Threads
129,911
Posts
1,823,325
Members
93,304
Latest member
natedawg
Top