Help on brake light diagnosis?!?!

[jb1dsl]

Ok here we go. I have a 66 fastback and finally got it all back together and ready to hit the road and low and behold brake lights dont work. The tail lights are workin but no brake or turn signals. I checked the ground and it cheked out but i get ne juice at the light. I checked the brake light switch and it is good ( hot one side, then hot when brake is mashed). where does it go from there? It looks like a green and something wire out of the brake light switch. Then maybe to the column?? Turn signal Switch??? any connectors to check, where are they? HELP!!!!!!!

 

[WhiteFox342]

If the brake light bulb and turn signal bulb are then same then the problem is in the turn signal switch. The power from the brake light switch goes through the turn signal switch before going to the brake bulbs.

 

[jb1dsl]

they are the same, a 1157 bulb

 

[jb1dsl]

how big of a chore is changing the turn signal switch?

 

[BarnStang]

Unless you want to cut & splice your connecter on, you will need to extract the pins from your column shell. THere are a couple things you can check first. Check with your test light at the column shell/plug/connector (with it connected together) on the Orange/blu stripe wire and the Green/org stripe wire with the brake pedal pushed. Those are the left and right brake lights leving the turn signal switch. DOn't worry about the turn signals yet-oh, do make sure the turn sig switch is in the center or off position. If you get nothing, then it's the switch, if it's good there, check the connecters above the drivers kick panel. Should be a small two wire white plastic connecter.

 

[MrBobMarley]

Bad flasher maybe?

 

[Tim65GT]

BarnStang:
THere are a couple things you can check first. Check with your test light at the column shell/plug/connector (with it connected together) on the Orange/blu stripe wire and the Green/org stripe wire with the brake pedal pushed. Those are the left and right brake lights leving the turn signal switch.

+1

Before changing the turn signal switch, you should check to see what the voltage is coming out of the switch at the plug. It should be the 2 pin connector with the Org/blu and Grn/org wires. Check with the brake pedal pushed and then check with the turn signal switch in both left and right (ignition on) as the flasher gets its power from ign source and the brake switch gets its power from battery source.

WhiteFox342:
If the brake light bulb and turn signal bulb are then same then the problem is in the turn signal switch. The power from the brake light switch goes through the turn signal switch before going to the brake bulbs.

There is only one bulb (each side), which means that it could also be the issue if both were bad. If the power is good at the signal switch, check at the bulb sockets.

 

[jb1dsl]

Well I found the problems. I began by checking the voltage at connector leaving the turn signal switch and low and behold voltage. I follwed the leads done the kick panel, under the sill plate , into the trunk and then to the plug. I had an extra set of hands and feet tonight, so it was alot easier. First i confirmed taillight voltage, then brake light voltage and turn signal voltage. I checked the bulbs and they were fine. I then began to wiggle the old plug around and then all of a sudden, LIGHTS!!! Any time i bump them or wiggle them they fluctuate or go out. Is there a trick to get the contacts inside the socket to make better contact. Can i put dielectric grease on the inside of the socket, where the pins are to lube it up for better contact??

Thanks too everyone, especially barnstang anf tim

 

[carefact0rzero]

my passenger side park light used to do that, i took a pair of pliers and squeezed the plug just a bit, now it fits pretty tightly...

 

[Tim65GT]

jb1dsl
I checked the bulbs and they were fine. I then began to wiggle the old plug around and then all of a sudden, LIGHTS!!! Any time i bump them or wiggle them they fluctuate or go out. Is there a trick to get the contacts inside the socket to make better contact. Can i put dielectric grease on the inside of the socket, where the pins are to lube it up for better contact??

I doubt the grease will help much. On mine (a few years ago), it was the springs that put pressure on the contacts. They were rusty and weak. You can cut the wires behind the housing, pull the bulb, push them through, and you can replace the springs from a another light socket, then re-connect the wires by solder or crimping. I used a soldering iron and unsoldered the contacts on mine to replace the springs. The small plastic insert should only go back in one way.

 

[jb1dsl]

do the new taillight buckets come with the socket???

 

[Tim65GT]

jb1dsl
do the new taillight buckets come with the socket???

Looks Like it on this pic from Mustangs Unlimited. Might want to call your vendor first and ask.

 

[jb1dsl]

Yeah, I looked at that pic. I will see how the lights work for the next few days. I usually order from mustangs unlimited so I will call them if I need to order some.