Automotive Check Engine Light Codes Resource
- Diagnostic procedures for the check engine and service engine soon light with trouble code descriptions and test procedures.
- http://www.engine-light-help.com

Automotive Online Electrical Tutorial
- Covers basic electrical issues, alternators, relays and circuitry.
- http://www.autoshop101.com/autoshop16.html

OBD-II - On-Board Diagnostic System
- Dedicated to helping the home and independent technician understand and use OBD-II technology through text, photos, and a discussion forum.
- http://www.obdii.com/

HowStuffWorks: How Turn Signals Work
- Photographs and animations describe the unusual device called a thermal flasher that makes your signals flash, and shows how turn signals cancel themselves after you've made your turn.
- http://www.howstuffworks.com/turn-signal.htm