Wiring from RV 7 way to Toad vehicles existing lights?

No. You can not run from the MH 7 pin to the Jeep's 7 pin. There are 3 options.

1. Use removable (magnetic) lights. They can be mounted on the back of the car or on a metal bar in the car's trailer hitch. No diodes needed.

2. Drill a hole in each of the car's tail light fixtures and install a new 1157 bulb/socket. No diodes needed.

3. Connect the wiring to the car's existing tail/brake lights. A diode is needed on each side.