DH had the best idea for checking the brake lights if you are alone.
There are three wires in the plug for the flasher marked "A", "B", and "C". "C" is the ground and should be checked first. If you still have no lights following a verification of a good ground, it may be the flasher. To verify, simply make a small jumper wire to slip in from "A" to"B" (installed on the plug) with the plug unplugged, and you should have brake lights and a "steady" burning directional light. If nothing is working with the jumper in, then the issue is elsewhere.
I had my flasher fail this summer after I plugged in my M332 (that had an unknown short to ground). I will be doing the relay mod the Bjorn came up with.
This is the correct answer to my question and pretty much straight out of the TM.
It's too cold to go out at night here. It is actually getting down below freezing now.
27. BOTH DIRECTION SIGNALS INOPERATIVE
Test 1. Test left and right flashers.
Step 1. Turn main light switch to SERVICE DRIVE position.
Step 2. Position turn signal lever to LEFT position.
Step 3. Position turn signal lever to RIGHT position.
a. Both left and right turn signals should flash.
b. If turn signals fail to flash, go to test 2.
Test 2. Test solid state flasher.
Step 1. Disconnect leads 467A and 467B from solid state flasher pins A and B.
Step 2. Connect jumper wire from leads 467A to 467B.
Step 3. Place turn signal lever to LEFT position.
Step 4. Place turn signal lever to RIGHT position.
a. Left and right turn signals should work but will not flash. If turn signals work, replace
turn signal flasher (para. 4-20).
b. If voltage is not present, go to malfunction 25 and perform tests 1 through 8.