Left brake light doesn't come on

[airman_x]

Howdy,

I hope someone can shed some light on this problem.

Both turn signals work, but the left brake light does not. There is no power to the wire at the connection (connection W on the schematic I downloaded from Fordification.com) when the brake pedal is pressed. When the emergency flashers are on, the rear left is the only one not working.

Any ideas?

The way I understand it from the schematic (http://www.fordification.com/images/sch ... _81-85.jpg), there's a 20 amp fuse that supplies power to the emergency flasher via wire 383. Since 3 of 4 flashers work I have to assume there's power there. At the flasher, there's a tap, wire 284 that goes to the stoplamp switch. When the brake is pressed, the switch closes and wire 810 becomes hot. Wire 810 goes to a terminal block in the turn signal switch where it connects to wire 10. Wire 10 must be okay since the right brake light works. Wire 10 looks like it connects to wires 5 and 9 in the turn signal switch. From there, wires 5 and 9 are connected to wires 282 and 283. When wires 282 and 283 are energized, the brake lights come on. Could the problem be where wire 10 is jumpered to wire 9 in the turn signal switch?

Steve

[bluef250]

Most likely the problem is in the turn signal switch as you have figured out. The switch is the weak link in the electrical system.

[seattle67]

Good job following the wiring diagram, you're definitely on the right track.

Obviously the power going into the turn signal switch (TSS) on wire #10 is good, if you have a meter or test light, I would check to see if you have power coming out of the TSS on wire #9 when you push on the brake pedal or have the emergency flashers on. If you don't have power then yes, it could be that jumper in the TSS or a contact in the switch itself. If you do have power, then just keep doing what you were doing, follow the path towards your left brake light, wire #283, and find the point where you lose power.

[kaptnkaos]

I just had exactly the same problem with my '68 CS.
Everything worked except the p.side brake light, I checked the grounds and everything...
It ended up being the brand new turn signal switch not making a connection.
I removed the steering wheel and checked the switch...
I loosened it moved it a little and it started working... so I put everything else back together.

KaptnKA S

[airman_x]

Thanks for all the help. When I bought the truck, the guy who sold it to me said he replaced the turn signal switch. I'll take the steering column apart and check the wiring.

This web site and people on it are great!

Steve