Third brake light help

[drdave69]

My third brake light doesn't work and I have spent many hours on it trying to troubleshoot the problem. I have tried everything that I know of without success. I tapped into the yellow brake light wire (with the blue 3rd brake light wire) and it would then function. But, it would also blink with the turn signal (of course). I have checked the voltage at the main rear harness plug to the blue wire and it is 12v but when everything is plugged together it still doesn't work. I have tried many more solutions to no avail.
Can anyone help?

 

[garyk1970]

get a test light and set brake pedal,test blue wire on BOTH sides of the plug in the trunk near passenger tail lamp(where all lamps and fuel pump come from the "hard wires" to soft normal wires).

check the light and fuel pump ground in that area too.

the hard type wire has issues with age,also check at the fuse block.



the emergency switch and/or connections at the big plug in trunk or fuse block,and hard wire harness itself are likely to fault. easiest fix is tie the blue 3rd lamp wire to the white wire on the brake switch itself.... the plug your looking for has a orange and white wire on it only.connect the blue wire to the white wire on the brake switch....

 

[bosted86]

Did You Remove The Third Light Assembly And Check The Wiring. My Wasn't Working And I Found That The Wire Inside The Lights Was Loose.

 

[salvageV6]

Pin C of the brake pedal switch is a light blue with black stripe wire, it runs the third brake light system and that only. It is fed by the same orange wire that feeds the white output brake switch wire so you can start there since that part of the circuit is working.

Check the wire/connector there for power when you step on the pedal.

After that, C209 is an 11 cavity connector to the left of the fuse panel that the wire goes through, light blue is the output wire of that connector, after that it goes to C320 in the left corner of the trunk another connector and changes back to light blue with black stripe until it gets to the connector at the light itself.

You can check for power on those wires from front to back, or back to front by putting a brick on the brake pedal, make sure the other lights are on as well.

 

[drdave69]

Pin C of the brake pedal switch is a light blue with black stripe wire, it runs the third brake light system and that only. It is fed by the same orange wire that feeds the white output brake switch wire so you can start there since that part of the circuit is working.

Check the wire/connector there for power when you step on the pedal.

After that, C209 is an 11 cavity connector to the left of the fuse panel that the wire goes through, light blue is the output wire of that connector, after that it goes to C320 in the left corner of the trunk another connector and changes back to light blue with black stripe until it gets to the connector at the light itself.

You can check for power on those wires from front to back, or back to front by putting a brick on the brake pedal, make sure the other lights are on as well.

I have done all of the checks in the trunk area. The blue wire in the trunk harness gets 12v with the pedal pressed but it will not illuminate the 3rd light when jumped directly from the main harness plug (bypassing the dedicated rd light plug). I can move the jumper wire to the yellow or green wire and the 3rd light will illumniate. This may be easier to cover over an actual phone conversation if someone has the time this evening.

 

[salvageV6]

You now need to read the voltage with the lamp hooked up to the wiring.

If it drops to 0 volts with the bulb in circuit there is no current behind the voltage off the switch and through those connectors.

At that point a test lamp setup should be made using a brake light bulb or a trunk light bulb (89) with wire leads, and see if it illuminates where you see power on the blue wires, using a good body ground on the other bulb connection.

If that lamp lights up you know the wiring is good and has sufficient current at that point.

Should be easy to check at the left trunk connection with a test lamp.

 

[drdave69]

Thanks a ton for the help. I tackled this again last night and started at the brake pedal switch. There was no voltage to the light blue wire at the C209 connector. I removed the brake switch, opened it up and cleaned all of the contacts. I also tightened the pressure points in the switch. Reinstalled the switch and now everything is working. I should have started there in the beginning and saved myself many hours of aggravation.
Again, thanks for the guidance.

 

[Heath]

third brake light

I had the same problem it all checks out with a test light.Change the switch on the brake pedal.

 

[drdave69]

Heath, no need to change the switch. See my previous post.

 

[Heath]

I know now. Oh well live and learn:biggrin:

 

[Heavy1287]

I've been messing with my switch for almost a year. The 3rd brake light works when I take the switch apart, but as soon as I put the plastic retainer back on it goes off. I've tried tightening the contacts with no success. I went to O'Reilly's today for a new switch, and had to order the Stop Light Switch and Torque Converter Clutch as it was what was called for. I've never heard of the torque converter clutch part of the switch, and am wondering if people have just put on a compatible switch? One is on order anyway...

 

[grandnash84]

Pin C of the brake pedal switch is a light blue with black stripe wire, it runs the third brake light system and that only. It is fed by the same orange wire that feeds the white output brake switch wire so you can start there since that part of the circuit is working.

Check the wire/connector there for power when you step on the pedal.

After that, C209 is an 11 cavity connector to the left of the fuse panel that the wire goes through, light blue is the output wire of that connector, after that it goes to C320 in the left corner of the trunk another connector and changes back to light blue with black stripe until it gets to the connector at the light itself.

You can check for power on those wires from front to back, or back to front by putting a brick on the brake pedal, make sure the other lights are on as well.

hey was wondering if you could help me out with my third light. so far, i changed the bulb, new housing and won't light up. im getting 12v at the connector to the housing and 12v at the socket when the brake is applied and no light. i get 0 volts at pin c of the brake pedal (blue/black and white, orange only wire that has power) switch and the c209 connector. im stuck right now, any pointer on what to do next. its throwing me off i have voltage at the light but not the brake switch. thx!

 

[salvageV6]

Was your third brake light added on to the car or factory?

I don't see how you can have 12 volts at the bulb if you don't get 12 volts out of the brake light switch on the blue/black wire?

 

[captndave737]

I've been messing with my switch for almost a year. The 3rd brake light works when I take the switch apart, but as soon as I put the plastic retainer back on it goes off. I've tried tightening the contacts with no success. I went to O'Reilly's today for a new switch, and had to order the Stop Light Switch and Torque Converter Clutch as it was what was called for. I've never heard of the torque converter clutch part of the switch, and am wondering if people have just put on a compatible switch? One is on order anyway...

It unlocks the torque converter when the brake is applied.

 

[dank GN]

Someone put a complete manual on line check it out it has everything
http://onefootinthegrave.net/filez!/warez!/trservice/enhcdpdf.html