Automotive Service Excellence (ASE) A6 Electrical/Electronic SystemsBattery Diagnosis and ServiceMedium

A technician is installing a new battery in a vehicle. After placing the battery in the tray and securing it, what is the correct sequence for connecting the battery cables?

  1. AConnect the negative (-) cable first, then the positive (+) cable.
  2. BConnect the positive (+) cable to the starter, then the negative (-) cable to the engine block.
  3. CConnect the positive (+) cable first, then the negative (-) cable.
  4. DConnect the negative (-) cable to chassis ground, then the positive (+) cable to the battery.
Show answer & explanation

Correct answer: C. Connect the positive (+) cable first, then the negative (-) cable.

When installing a battery, always connect the positive (+) cable first. This prevents accidental short circuits if a tool touches the chassis while connecting the positive terminal, as the negative terminal (and thus the chassis) is not yet connected to the battery.

Why the other options are wrong

  • A. Connecting the negative cable first increases the risk of a short circuit if a tool touches the positive terminal and then the chassis.
  • B. While these are correct connection points, the order is crucial; the positive to the battery terminal (which then goes to the starter) should be first.
  • D. This describes the connection sequence for a charger, not for installing the battery cables to the battery itself.

Battery Cable Connection Sequence

When installing a battery, always connect the positive (+) cable first, followed by the negative (-) cable, to minimize the risk of accidental short circuits.

  • Install: Positive (+) first, then Negative (-).
  • Remove: Negative (-) first, then Positive (+).
  • Prevents sparks and short circuits.
  • Ensures safety during installation/removal.

Memory trick: Positive Power First, Negative Last, Safety's Fast!

More Battery Diagnosis and Service questions