3rd brake light STILL doesnt work
Thread Starter
Team Owner
Joined: Sep 2001
Posts: 62,119
Likes: 1,725
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
3rd brake light STILL doesnt work
Replaced all 4 bulbs-nothin
Replaced the switch at the pedal, checked connections which looked ok-nothing happened.
So what do i do now. :confused:
Replaced the switch at the pedal, checked connections which looked ok-nothing happened.
So what do i do now. :confused:
Racer
Joined: Aug 2002
Posts: 259
Likes: 0
From: Chicago Suburb Illinois
Re: 3rd brake light STILL doesnt work (vader86)
Try checking with a test light at the bulb sockets if you have 12v. If not then try checking if the housing has a good ground. You could try running a external wire to good ground and see if it works. Try to determine what side of the circuits are not working. Wiil check schematic, if I come up with something I'll repost. goood luck :cheers:
Racer
Joined: Aug 2002
Posts: 259
Likes: 0
From: Chicago Suburb Illinois
Re: 3rd brake light STILL doesnt work (vader86)
Vader, best I can do on the schematic. :cheers:
12.250.128.183/tech/stoplmp.jpg
12.250.128.183/tech/stoplmp.jpg
Thread Starter
Team Owner
Joined: Sep 2001
Posts: 62,119
Likes: 1,725
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: 3rd brake light STILL doesnt work (Mike_D)
So, is it possible that there may be a bad connection at the ABS, that would not affect the rear lights?
Drifting
Joined: Aug 2002
Posts: 1,773
Likes: 123
From: Birmingham AL
Re: 3rd brake light STILL doesnt work (Mike_D)
I sort of have the same problem with my '89 coupe. Not all of bulbs work even when they are new. It pizzes me off when I spend $45 on light bulbs for a third brake light and they don't all work. I think that my housing base is cracked or something and not allowing for a complete circuit on all the bulbs. When I replaced all 4, 3 of them worked. Only a few months later, I am down to one working bulb. I think I need a new bulb base.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: 3rd brake light STILL doesnt work (vader86)
Is 12v across the two wires on the stoplight circuit board with the brake pedal depressed? Is the ground wire on the circuit board going to ground? Are the spring contacts that make with the bulb pins in good condition? If 12v is on the two wires, is it also on the two printed circuit conductors on the ciruit board?
Thread Starter
Team Owner
Joined: Sep 2001
Posts: 62,119
Likes: 1,725
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: 3rd brake light STILL doesnt work (jfb)
Is 12v across the two wires on the stoplight circuit board with the brake pedal depressed? Is the ground wire on the circuit board going to ground? Are the spring contacts that make with the bulb pins in good condition? If 12v is on the two wires, is it also on the two printed circuit conductors on the ciruit board?
Thread Starter
Team Owner
Joined: Sep 2001
Posts: 62,119
Likes: 1,725
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: 3rd brake light STILL doesnt work (vader86)
I can tell you what i was thinking of doing, i was going to depress the pedal and see if there was any current getting to the 3rd brake light connection on the switch. (new switch tho) and i'm going to check to see if any current is getting to the bulbs at the connectors, but i dont know what to check for in between.
Its highly possible that the ground has been disconnected, apparently the prior owners didnt know jack about wiring and have screwed a few things up in the car.
Its highly possible that the ground has been disconnected, apparently the prior owners didnt know jack about wiring and have screwed a few things up in the car.
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Racer
Joined: Jan 2003
Posts: 321
Likes: 0
From: Birmingham AL
Re: 3rd brake light STILL doesnt work (vader86)
Vader - Check 12V at the switch.
Check 12V at the lights. If you have 12V there, then you have lights (assuming a good connection at the bulbs.)
There is a possibility of a bad ground.
I'm looking at the schematic ... Follow up later ...
Jim
Check 12V at the lights. If you have 12V there, then you have lights (assuming a good connection at the bulbs.)
There is a possibility of a bad ground.
I'm looking at the schematic ... Follow up later ...
Jim
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: 3rd brake light STILL doesnt work (vader86)
The four sockets that you plug the light bulbs into on the 3rd brake light is a printed circuit board. Two wires are soldered on the circuit board that go to 12v from the brake switch and the other wire goes to ground.
Drifting
Joined: Jan 2002
Posts: 1,261
Likes: 4
From: Middle River MD
Re: 3rd brake light STILL doesnt work (vader86)
This probably isn't your problem but you never know...I replaced my 4 bulbs recently and they were not coming on when brakes were applied. I lifted the hatch glass and noticed with it open they worked, but did not when it was closed. So I folded/twisted the wires to the light housing in a different direction and they started working. Maybe a wire or wires were getting pinched or something with the glass closed, I dunno but that fixed it and they have worked since.
