We had some really cold weather last week, cold enough to trigger my engine light actually, though ODBII shows 0 errors, When it warmed up the light went off.

Also, the brake lights quit. Middle/3rd light works on the cab, just the 2 on the box are now dead. Bulbs seem fine.

Would this be a switch? or I read somewhere the front control module? which I also read some say just swap it, and some say Dodge has to do it because of programming?Hoping a part I can get used and do myself.

any ideas how/where to start testing?

 

I'd recommend testing your brake lamp switch first. You'll see it contacting the brake pedal, just trace the pedal up.
Disconnect the switch harness: Turn the release lever then remove the harness.
Remove the switch from its mount: Push on the brake pedal then rotate the switch counterclockwise then pull it out of the bracket from the rear.
You'll see six pins. You should have continuity between pins 1 and 2 with plunger extended. You should have continuity between 3 and 4, and, between 5 and 6 with plunger retracted. If it fails any of the continuity checks then switch is bad and needs to be replaced.

 

Dumb question but, switch or FCM... why does the 3rd brake light still work? would have thought if one went out, they'd all go out. 2 switches? or 1 switch 2 outputs?

 

The rear lights also go thru the multi-function (turn signals) switch. The third eye does not. Do your turn signals work?

 

Yes... and no....

Other issue I have is that the front/right turn signal keeps blowing bulbs. Good not cheap ones too. Not sure if a power surge deal, bad wire, bad socket. In Canada and well, too cold to figure it out right now.

But, with working bulbs, they (last I checked) are working.

 

Check the grounds..... (when it warms up. )

Are you getting any 'lamp out' messages on the dash?

 

Ya, came on when the front/left turn signal blew again, which is still out. I'm outside for working on the truck, and last week was almost -30 degrees and a foot of snow so, gathering info now and first dry day I'll be out doing stuff.

 

The brake lights control panel are known to go bad. (The board the lights connect to) I would have someone press the brake and (with a test light) see if you are getting power back to the lights.