Need some help no brake lights.

[05blackduramax]

I got pulled over today on my way to work for not having any brake lights. If the bottom switch is in the park position no lights come on. The B.O. markers,B.O. drive both work.When in ser drive all lights work but no brake lights. When in the stop,signal postion only the turn signals work no brake lights. I did notice today when I got home it seemed like the switch was hot. Any one have any ideas thanks.

 

[doghead]

Start with the basics(before posting).

Did they ever work?

Look under the truck, is the switch unplugged?

Are your bulbs good?

Is there power at the switch?

Does the switch "close"?

Do you have good grounds at the light fixtures?

Have you read and followed the complete troubleshooting procedure in the -20 TM(and are still stumped)?

 

[05blackduramax]

I just looked at the TMs, the lights used to work,and the tail lights are led. I have all ready checked the basics thats why Iam posting. I got off work at 9am and been trying everything.

 

[doghead]

So, does the switch have power to it(with the 3 lever switch in either right side position?

You can unplug it and simply "jump" the two plugside wires together and see if they come on.

 

[05blackduramax]

Have the ? you asked are in my first post.

 

[05blackduramax]

Yes,the switch does have power.

 

[doghead]

Have the ? you asked are in my first post.

Start with the basics(before posting).

not covered in first post, Did they ever work?

not covered in first post,Look under the truck, is the switch unplugged?

not covered in first post,Are your bulbs good?

not covered in first post,Is there power at the switch?

not covered in first post,Does the switch "close"?

not covered in first post,Do you have good grounds at the light fixtures?

not covered in first post,Have you read and followed the complete troubleshooting procedure in the -20 TM(and are still stumped)?


I don't see any answered in the 1st post.​

 

[05blackduramax]

I think the grounds are good all lights work but the brake lights when in ser drive on the switch.

 

[05blackduramax]

Ok sorry,the plug is tight,all the wires along the frame look good.

 

[doghead]

Unplug the switch plug, and use a piece of wire to "jump" the wires, and look at your brake lights to see if that makes them come on.

MAke sure your light switch is on too.

 

[doghead]

What truck are we talking about?

 

[05blackduramax]

M931a1

 

[steelandcanvas]

opcorn:

 

[05blackduramax]

I got 22.7 volts from F to A, A is the stop lights. When I jump them with a wire I still get no brake lights. F to L I have 25.3 volts,when I jump them shouldnt I get the park lights?

 

[05blackduramax]

Iam getting 27 volt back to the stop switch wire 75 to ground. Pluged 75 back it switch and checked switch with brake pedal pressed, brake lights work. Dont know what happed there. I still have no park light with the bottom switch in the park postion.

 

[Suprman]

When you initially switched to led lights did you visually verify that everything worked as it should?

 

[doghead]

Have you looked at the page in the -10 TM that explains the headlight switch operation?

Park, actually turns the headlights off in service drive.

Be sure you read and understand the headlight switch operation clearly.

 

[05blackduramax]

I Didnt know that thanks.

 

[doghead]

Look at this.