I replaced the 1156 lamp in the 3rd brake light and it works correctly.
HOWEVER, it shows as being 'out' on the dash light monitor screen.

I just bought a brand new battery and when we changed it over, the above problem was absent - UNTIL I stepped on the brake pedal for the first time after the battery installation.
It is now back to its old 'working but showing its not working' trick.

Any suggestions on this PITA? That'* PAIN IN THE A$$. :?

The ALM is detecting the wrong current to that circuit. Try checking for frayed/shorted wires.

I had that happen when I installed another part number (12V RV bulb). Bulb worked, but the draw was off just by a bit. I'd verify you have the right bulb in there......and clean the socket very well.

I'll check it out this weekend.