How To Diagnose: Inspection

Sight and sound checks
Check relay operation, blower motor rotation, light illumination, etc. Listen for a "click" when some relay covers are pushed down.

Fig 1: Checking Relay Operation
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Simple checks
For example, if a headlight does not come on and a faulty fuse or poor grounding is suspected, replace the fuse with a new one. Or use a jumper wire to ground the light to the body. Determine which part(s) is/are responsible for the problem.

Fig 2: Identifying Good/Faulty Fuse
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Checking with instruments
Use an appropriate instrument in an adequate range and read the indication correctly.

Fig 3: Checking Range With Instruments

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.