No Brake Lights?!
Thread Starter
Burning Brakes
Joined: Apr 2001
Posts: 752
Likes: 1
From: Springfield Oregon
No Brake Lights?!
Suddenly I have no brake lights. Had 'em last week. Switch is OK. Have 12V to one side of the switch lead. I'm not quite sure what is supposed to be going on down there for electricity. Can anyone help me with a plan of attack. Bulbs are OK. Have tailights and flashers/turn signals. Fuses in panel are OK. Thanks for any help.
Thread Starter
Burning Brakes
Joined: Apr 2001
Posts: 752
Likes: 1
From: Springfield Oregon
Re: No Brake Lights?! (ORVette)
I have 12V on each side with the switch closed(brakes on). That's measuring from each terminal to ground. Now, if I check from terminal to terminal I have nothing. anywhere I should check for voltage between the switch and the lights? This one has me baffled.
Melting Slicks
Joined: Mar 1999
Posts: 2,845
Likes: 2
From: Apex NC
Re: No Brake Lights?! (ORVette)
Check the ground on the tail light housings themselves. If they aren't grounded back there then you ain't gonna get no lights. Also check to see if there is voltage at the bulb in the tail lamp. If you have voltage, then it must be a ground problem. If you don't have voltage, then it's a problem in the wiring between the brake light switch and the rear lamps.
Also, does the hazard flasher work? If so, you've isolated it to the brake light circuit rather than the ground at the rear lamps.
Shannon
Also, does the hazard flasher work? If so, you've isolated it to the brake light circuit rather than the ground at the rear lamps.
Shannon
Drifting
Joined: Mar 2001
Posts: 1,411
Likes: 2
From: St. Louis, Missouri
Re: No Brake Lights?! (sb69coupe)
With the pedal depressed, if you have 12 vdc from each terminal to ground, the switch is good. With the pedal released, you should only have 12vdc between just one terminal and ground, the other terminal should indicate 0 vdc.
Checking for vdc between terminals won't do any good. For this, you would have to switch your meter to the ohm scale to check for continuity. The car's battery should be disconnected as well because checking for continuity with voltage on the circuit is a no-no.
With each meter lead (red and black) on a terminal of the switch, the meter should show an open (infinity resistance or no continuity). When the switch is activated, the meter should show zero or near zero resistance (good continuity.
Other than all of this, the info provided by sb69 is good advice.
Checking for vdc between terminals won't do any good. For this, you would have to switch your meter to the ohm scale to check for continuity. The car's battery should be disconnected as well because checking for continuity with voltage on the circuit is a no-no.
With each meter lead (red and black) on a terminal of the switch, the meter should show an open (infinity resistance or no continuity). When the switch is activated, the meter should show zero or near zero resistance (good continuity.
Other than all of this, the info provided by sb69 is good advice.
Thread Starter
Burning Brakes
Joined: Apr 2001
Posts: 752
Likes: 1
From: Springfield Oregon
Re: No Brake Lights?! (ORVette)
The switch is tests good. Thw voltage in and out test good. I do have tailights and flashers, so that's good. Must be something in between the switch and the rear lamps, I just can't imagine what. I'll be in the garage if you need me.
Thread Starter
Burning Brakes
Joined: Apr 2001
Posts: 752
Likes: 1
From: Springfield Oregon
Re: No Brake Lights?! (ORVette)
OK, so I go under the dash and check where the main dash harness plugs into the rear lighting harness. If I read it correctly, the dark brown wire is for taillights, and the dk. green and yellow wires for the brake lights/turn sig/hazard. So with the brake switch closed, 12V on both sides, I probe the dk. green and yellow wires. Nothing. Now, key on, I turn on the r&l turn signals and the meter reads them working(yellow=left,dk.green=rt). Brake lights don't work with key on either, not that it should matter. Could this be a problem inside my steering column? The rough schematic(HAYNES) I have makes it appear that the white wire from the brake light switch runs up through the column and into and out of the turn sig/hazard switch mechanism's, then splits to yellow and dk. green and back down to the plug under the dash. Any thoughts appreciated.
