All lights work except brake lights
- Thread starter hambo
- Start date
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.
350runner
Full Access Member
- Joined
- Feb 9, 2013
- Posts
- 2,858
- Reaction score
- 224
- Location
- tx
- First Name
- Ceasar
- Truck Year
- 82
- Truck Model
- c10
- Engine Size
- 350
That was my problem. Yours could be different. I try to share my experiences so anyone reading could add things to thirty check list 
Sent from the dust in front of you!
Sent from the dust in front of you!
hambo
Full Access Member
- Joined
- Dec 11, 2014
- Posts
- 92
- Reaction score
- 0
- Location
- illinois
- First Name
- Ian
- Truck Year
- 1987
- Truck Model
- k20
- Engine Size
- 454
Yeah. I understand. Might not be the same problem but it can't hurt to try it. Thanks for your help!That was my problem. Yours could be different. I try to share my experiences so anyone reading could add things to thirty check list
Sent from the dust in front of you!
chengny
Full Access Member
- Joined
- Feb 22, 2012
- Posts
- 4,084
- Reaction score
- 1,024
- Location
- NH
- First Name
- Jerry
- Truck Year
- 1986
- Truck Model
- K3500
- Engine Size
- 350/5.7
Checked the brake light switch and the lights didnt light up even when I connected them with a paperclip. so that rules out it being the switch.
Are you sure you jumped the correct wires?
I ask because there can be other circuits that utilize that switch (different contacts within it anyway). The previously posted image shows a brake light switch that also has wires connected (and contacts inside that cut out the TCC when the brakes are applied). Also, there maybe another switch altogether that disables the cruise control when the brakes are applied.
Just to be sure, the leads you want to pull from the tabs on the switch should be white and orange.
If you stick a clip into the sockets that correspond to the white and orange wires and you don't get brake lights - then you can eliminate the switch.
And, considering the amount of work you are doing on that circuit (which is always hot - even with the key off) it would be wise to check the fuse that supplies it. I think it should be labeled STOP/HAZ. It would suck to do a bunch of troubleshooting only to find out that you blew the fuse while testing.
Are you sure you jumped the correct wires?
I ask because there can be other circuits that utilize that switch (different contacts within it anyway). The previously posted image shows a brake light switch that also has wires connected (and contacts inside that cut out the TCC when the brakes are applied). Also, there maybe another switch altogether that disables the cruise control when the brakes are applied.
Just to be sure, the leads you want to pull from the tabs on the switch should be white and orange.
If you stick a clip into the sockets that correspond to the white and orange wires and you don't get brake lights - then you can eliminate the switch.
And, considering the amount of work you are doing on that circuit (which is always hot - even with the key off) it would be wise to check the fuse that supplies it. I think it should be labeled STOP/HAZ. It would suck to do a bunch of troubleshooting only to find out that you blew the fuse while testing.
Last edited:
hambo
Full Access Member
- Joined
- Dec 11, 2014
- Posts
- 92
- Reaction score
- 0
- Location
- illinois
- First Name
- Ian
- Truck Year
- 1987
- Truck Model
- k20
- Engine Size
- 454
I jumped both plugs that went onto the prongs on the brake switch and nothing. And I already checked the fuses. I might check the brake switch one more time to be sure
chengny
Full Access Member
- Joined
- Feb 22, 2012
- Posts
- 4,084
- Reaction score
- 1,024
- Location
- NH
- First Name
- Jerry
- Truck Year
- 1986
- Truck Model
- K3500
- Engine Size
- 350/5.7
Do you have power coming into the switch on the orange wire? That is the hot leg and - because the brake lights are designed to work even with the key OFF - should show 12V always.
hambo
Full Access Member
- Joined
- Dec 11, 2014
- Posts
- 92
- Reaction score
- 0
- Location
- illinois
- First Name
- Ian
- Truck Year
- 1987
- Truck Model
- k20
- Engine Size
- 454
Yes I have power coming into the switch. So I still haven't gotten around to fixing my brake lights. Today, I was wiring clearance lights to my tool box, and the open metal connection running power for my clearance lights touched the bed, and the brake light lit up! So did the reverse lights which have never worked! So since the metal connection, which is plugged into my 4 pin trailer harness, caused the lights to light up does that mean its a problem in the wiring?
PrairieDrifter
Full Access Member
- Joined
- Dec 28, 2014
- Posts
- 3,877
- Reaction score
- 5,710
- Location
- North Dakota
- First Name
- Mason
- Truck Year
- 84,79,77,76,70,48
- Truck Model
- Suburban k10, bonanza k10, k30, k20, c10, gmc 1/2ton
- Engine Size
- 350, 350, 350, 350, 350, 350
If that's the case then you are missing a ground somewhere, the wire may have broke or the connection isn't good. Which wire touched the bed though?
hambo
Full Access Member
- Joined
- Dec 11, 2014
- Posts
- 92
- Reaction score
- 0
- Location
- illinois
- First Name
- Ian
- Truck Year
- 1987
- Truck Model
- k20
- Engine Size
- 454
okay Thanks. The wire that touched the bed was the running light wire in the 4 pin trailer wiring harness that I used to wire my clearance lights. The harness is plugged into the 4 pin trailer plug that connects the two brake light harnesses. I thought it was weird that it made both the brake lights get bright and the reverse lights come on.
hambo
Full Access Member
- Joined
- Dec 11, 2014
- Posts
- 92
- Reaction score
- 0
- Location
- illinois
- First Name
- Ian
- Truck Year
- 1987
- Truck Model
- k20
- Engine Size
- 454
Still trying to figure this out. Havent had much time to work on the truck lately. I noticed when i toich the running light wire together with the ground on my trailer wiring to my tool box, only the reverse lights come on. Dont know if that means anything though. Is it true that it could really be a ground even if the two tailights still work as turn signals and marker lights?
