Ya well this is not exactly an internship but there a course on automobiles in Mahindra pride school(MPS), Bangalore for around 2 months,you can attend that and they will do placements in a automobile company. The course is completely free and once get placed u can work for 3 months in a automobile company like Tata, Mahindra, Toyota and others as a technician, Service Advisor or other(like CRO based on your resume). If u work for 3 months or more(3 months necessary) you will receive a certificate from MPS as certified student on Automobiles course and work experience certificate depends upon company.

Go via someone you know , apply via common internship websites like internshala or send a mail to the company's HR where you want to intern.

By contacting the HR department of companies your are interested with your resume and cover letter.