When I pulled the cruise control off of my Challenger, the brake lights stopped working. The cruise set up was not wired to the brakes at all (someone did a poor hack job when it was put in). I pulled my brake light switch and replaced it and that wasn't the problem. The wires to the switch have not been hacked, so I'm at a loss. Any thoughts?

Since the brake light "Feed" circuit travels through the "Hazard/Flasher" wiring of your particular turn signal switch, there times that the contacts have overheated and failed, thus not able to complete the "Stop" circuit. Start by pinning out at terminals of the T/S hard shell connector to verify current flow. This is of course a battery "Hot", not key "On" circuit.

brake light power originates at the brake fuse in the fuse box & goes out to the BL pedal switch in a pink wire which is hot all the time (think hot pink) then it goes from the pedal switch to the TS switch in a white wire. seperate the TS plastic pull apart connector & with the TS switch in neutral there should be continuity between the white wire terminal in the switch half of the connector to the (2) out terminals in that same switch half of the connector which are for the pass and drivers brake light filaments. grab your meter. also you can pull the drivers kick panel & seperate the connector & jump fire to the (2) terminals for the L/R brake lights to see if you are good downstream from there but I imagine you are since things were moved further upstream that caused the problem. On all of this have the hazard switch off. that'll get you started.

Pulled the can to check the switch and start testing continuity and the switch is broken and needs to be replaced. Does anyone sell a correct 1970 switch? All I found on the repro market doesn't have the right hazard knob.

Check the turn signal wiring connection.

I had a bad t/s switch in my 70 Challenger too. Base on advice in this site, I bought the readily available 71 and up switch, and drilled out the rivets holding it together. Take out the new hazard knob and contact, and put the one from your old switch in. Some very small screws and nuts plus a lock-washer will put the switch back together again, and it will then fit and look like an original.
Mark

Turns out Year One has a 1970 replacement now. They are having a 30% off sale, so I ordered one that was actually a decent price!