it plugs into the main harness block that is screwed into the firewall (where all the wires for the engine compartment and headlights are plugged into. If I remember right, it goes on the bottom right side (maybe the upper). You really should get a manual for the car (Factory Service manual); you can down load them for free as well. This will be exceptionally helpful; believe me every guy on here regards of experience level has a library of manuals (me included). Just to be clear, I am not trying to discourage you from asking questions, just saying that if you had the manual/s it will be much quicker and allow you to research a wide variety of issues/subjects rather than wait for someone here to answer.
70 Challenger RT 440-6, 73 Cuda (under const)
05 Durango, 99 Dakota, 01 Ram 4x4, 14 2500 4X4, 10 PCP Challenger RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR, 61 Jeep FC170
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)