Brake Light questions
Thread Starter
Racer
Joined: Apr 2008
Posts: 406
Likes: 46
From: Lebanon OH
Brake Light questions
I have a '79 and just realized the brake and hazard lights don't work. I have signal lights and tail lights. I pulled the brake switch, checked it with a ohm meter, and it seems fine. I have 12+ volts at the orange wire on the plug.
So here's the problem: when I check the power at the white wire on the harmonica plug, there is nothing with the brake switch open or closed. When I plug the brake switch partially in and check it against ground, it has 12+ volts on the hot pin when the switch is tab pressed in, and nothing at the hot pin when the switch tab is fully extended. Is it possible a brake switch could test good with an ohm meter and still not be working?
If the switch is good, does the white wire from the brake switch plug run directly to the hamonica plug? Finally, is it difficult to get a good voltmeter connection on the individual wires in the harmonica plug. I pushed the probe into the square on the the back until it stopped, and this seemed to work fine for the black ground wire on the voltmeter. Just wondering what to do next.
Regarding the hazard lights, I checked the brown wire for power, and there wasn't any. Does the brown wire come from the fusebox? Thanks.
MajD
So here's the problem: when I check the power at the white wire on the harmonica plug, there is nothing with the brake switch open or closed. When I plug the brake switch partially in and check it against ground, it has 12+ volts on the hot pin when the switch is tab pressed in, and nothing at the hot pin when the switch tab is fully extended. Is it possible a brake switch could test good with an ohm meter and still not be working?
If the switch is good, does the white wire from the brake switch plug run directly to the hamonica plug? Finally, is it difficult to get a good voltmeter connection on the individual wires in the harmonica plug. I pushed the probe into the square on the the back until it stopped, and this seemed to work fine for the black ground wire on the voltmeter. Just wondering what to do next.
Regarding the hazard lights, I checked the brown wire for power, and there wasn't any. Does the brown wire come from the fusebox? Thanks.
MajD
Instructor
Joined: Jul 2008
Posts: 123
Likes: 0
From: Wertheim Baden-Württemberg Germany
I have ,or had, the very same problem.No brake or hazzard lights.
(As you probably already know the brake and hazzard lights are on the same fuse output.)
When I test the connection,at the taillights, without the bulbs removed,I have 12 volts.I reinstalled only 1 bulb and had 0 volts.
Traced back to the output side of the brake light switch...same thing.
Went to the input side of the switch/output side of the fuse..... same thing.
Went to the input side of the fuse.....12V with or without the bulbs, but no brakelights.
Apparently the connection on the output side of the fuse is not able to deliver the current needed .Cleaned the contacts and inserted a new fuse with no luck.
I believe the contacts on the backside of the fusebox are corroded.Will have to mess with it in the winter.
I ran a wire ,with an inline fuse ,from BAT on the fusebox to the brake switch.Works fine.I have brake lights but still no hazzards.
(As you probably already know the brake and hazzard lights are on the same fuse output.)
When I test the connection,at the taillights, without the bulbs removed,I have 12 volts.I reinstalled only 1 bulb and had 0 volts.
Traced back to the output side of the brake light switch...same thing.
Went to the input side of the switch/output side of the fuse..... same thing.
Went to the input side of the fuse.....12V with or without the bulbs, but no brakelights.
Apparently the connection on the output side of the fuse is not able to deliver the current needed .Cleaned the contacts and inserted a new fuse with no luck.
I believe the contacts on the backside of the fusebox are corroded.Will have to mess with it in the winter.
I ran a wire ,with an inline fuse ,from BAT on the fusebox to the brake switch.Works fine.I have brake lights but still no hazzards.
Last edited by Ravoll; Aug 26, 2011 at 09:11 AM.
