Jeff,
I finally (!) remembered to bring in my service manual. Do you have the tow option on your rig or is the whole thing aftermarket? I have the wiring diagram open in front of me so we can work this out.
Bill is correct. The brake light voltage is on both wires to the turn signals when the brake is pressed. If you have only one brake light then you need to run a wire from wire L50 18WT/TN (white/tan) on the connector to the switch at the top of the brake pedal. This thing is only an 18 gage wire so you should use a relay to provide power to your light. If you have two brake lights, one on each side, and the trailer two package then connect the left to pin 5 of the connector and the right to pin 6. These are the vertical connectors on the side.
If you don't have the two package let me know and I'll hunt around in the diagrams some more.
BTW: If you don't have the Dodge service manual, run down to the dealer and get one. Cheap at twice the price.
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Joe George
Eureka, CA
'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,BD valve body,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver