Wires & Connectors:
BorgWarner (formerly Delphi)
Deutsch
Switches:
Relays:
Circuit Protection Devices:
Lead-Acid Batteries:
Electronics:
Alternators and Charging System Components:
http://www.prestolite.com (Leece-Neville alternators)
https://www.sure-power.com (DC-DC converters)
Cranking Motors:
http://www.delcoremy.com (Delco brand)
http://www.prestolite.com (Leece-Neville brand)
Truck Lighting:
https://www.sylvania-automotive.com/
Truck Accessories:
Trainings:
Automotive Training Websites:
Hunter Engineering (Alignment)
Auto Shop 101 (Electrical Systems)
Modern Trucks & Major Components:
http://www.allisontransmission.com
https://www.demanddetroit.com/ (Detroit Diesel)
Ignition Related:
Brakes:
Lubrication:
Troubleshooting:
Engine Related & Miscellaneous:
DRiV Heavy Duty Parts
Small Engines:
Motorcycles:
Marine Engines:
ASE
Diesel Engine Diagnosis Specialist L2 (PDF)
Digital Multimeters and Current Probes:
Measuring
Tools
Truck Body & Chassis Control Modules: