I found this site that offers free PDF repair manuals for the 2008-2018 Challenger. They are very comprehensive and include product specifications, part schematics, wiring diagrams, illustrations, troubleshooting guides and step-by-step service procedures. They literally show you how to remove a part, how to test if it is faulty, how to disassemble and clean it, and how to reassemble it and install in back on the car. (Note- These are huge files and contain about 7,400 pages). The site is clean. It has been checked with Malwarebytes, Superantispyware, Defender and Avast. Download Dodge Challenger Repair Manual | Repair Answers
