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Brake Lights and Turn Signal Issues

68stang289

68stang289

Member
I'm having two electrical issues with my 70.

Issue 1: The driver's side brake light does not come on when the brakes are applied. The passenger's side light comes on when the brakes are applied, but not the driver's side. I tried a fresh bulb with no luck. I also switched the bulb from the pass side to the driver's side that I know worked, and still no brake light. When you turn the headlights on, you get brake lights on both sides. Some of the wires on the rear harness I soldered back together due to them being cut by the PO. It is possible that that is the culprit, so in the morning (when I have someone who can help press the brake pedal) I'm going to run a test light before the solder point to see if there is power coming. Is there anything else that could be the culprit though?

Issue 2: The turn signals will not stay on. I can click the turn signal lever one way or the other and it will not stay in place. I also can only get the emergency flashers to flash when the headlights are off. I replaced both flashers with new ones that I assume are working just fine (why else would the flasher's work when the headlights were off?). Bad turn signal cam/switch?
 
Bad turn signal switch can account for everything you stated.

However, when you say when the headlights are on, both brake lights work. Did you mean to say both rear running lights work? Brake and turn signals are on the same line for the rear; running lights for the rear are on a separate line.
 
"Midlife" said:
Bad turn signal switch can account for everything you stated.
Running lights for the rear are on a separate line.
Click to expand...

Same thoughts here when reading subject title
 
"Midlife" said:
Bad turn signal switch can account for everything you stated.

However, when you say when the headlights are on, both brake lights work. Did you mean to say both rear running lights work? Brake and turn signals are on the same line for the rear; running lights for the rear are on a separate line.
Click to expand...

There's a lesson to be had here. Kids...don't drink and type! :lunc

Sorry, yes I meant to say that both rear running lights work when the headlights are on. If I disconnect the turn signal switch at the connector, should I be able to get both brake lights working if the turn signal switch is bad?
 
No, power from the brake light switch passes thru the turn switch out to the rear lights.
Replace the turn switch and fix it right.
 
"Mach1Rider" said:
No, power from the brake light switch passes thru the turn switch out to the rear lights.
Replace the turn switch and fix it right.
Click to expand...

Oh, I wasn't saying I wouldn't replace the turn signal switch. I just was hoping I could disconnect it to confirm the switch was bad before dropping the $100 for a replacement.
 
If you are extremely careful, you can jumper a single green wire to the orange/blue wire (RHS) and then to the green/orange wire (LHS) from the connector on the main underdash harness, bypassing the turn signal switch. The green wire will be next to the doubled up green/white wired pin.
 
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