No Flashers & Brake Lights...

[pcolette]

I haven't worked on that circuit in a while but I seem to recall that breaker #12 provided power for the brake lights. The whole flasher/headlights/relays/turn signal/etc. area is about as clear as mud sometimes. I would try using a voltmeter to check for power at the rear of breakers #11 and #12 to see that the breakers are actually working. It is possible for them to fail with the button still depressed and that may be your problem.

[Jimm391730]

I'd recommend that you follow this order:

1a. Do you get "flashing" power at the rear connection box (do you get 24V, then zero volts, 24V, zero, etc.) with the right turn signal on, then on a different wire with the left turn signal on? You MUST connect to a known good ground connection to make this measurement. If you do, then the problem is between the rear connection box and the ground at the lights. You may have to check all the possible terminals to find which is intended for the right side and which is intended for the left side. By using the turn signal you do not need an assistant to push the brake pedal, and you can trace down each side separately. Assuming you do get flashing power:

1b. Do you get flashing power at the light terminals? If you do, then the problem is bulb connections, bad bulbs, or bad grounds.

1c. Do you get flashing power at the ground connection in the lights? Then the light fixture ground is bad (ground should always measure almost zero, anywhere).

If the answer to 1a is no, you do not get "flashing" power anywhere to the rear connection box:

2a. Follow the wire to the connector under the dash (match the same wire color from front to back). Do you get flashing power to any pins there? If so, the wiring is open somewhere between the dash and the rear box, OR the connector is not making good connections and/or the crimps to the wires have corroded. Check both ends of the connectors.

2b. If no flashing power is at the correct connector, then compare trucks and follow the wires between the emergency flasher switch/flasher/turn signal switch (not sure what order these are connected in as you trace the wires) and look for other bad connectors or other damage to the wiring between the connector to the wires to the rear and the rest under the dash.

Let us know what you find as you go through this list, your answers might just spark an idea to find the problem. This should at least get you within a few feet of where the problem lies, and you can focus harder in that area.

Best of luck,

Jim