What is gm customer service phone number? GM Customer Service Phone Number. The Customer Service Phone Number of GM is: +1 313-556-5000 /. GM is the trading name of the General Motors Company which is an automotive manufacturer. GM company produces a vast range of automobiles, commercial vehicles and automobile parts from its over 396 manufacturing facilities in 37 nations across the world.What is gm global? GM Systems is a global management and technology leader focused on delivering innovative, customized advanced electronic systems, semiconductor components, and RF solutions to a global customer base of leading OEMs seeking high-performance, market-driven technologies. OUR TAGLINE: "COLLABORATE.What is gm financial phone number? Gm Financial Texas Customer Service Phone Number The Customer Service Phone Number of Gm Financial Texas is: 1-800-644-2297 / (817) 302-7000 / (1-800) 284-2271. GM is officially known as General Motors besides dealing in automobile it also deals in financial service.