Michigan SOS mechanic test

Electrical Systems

Electrical Systems (Automobile & Light Truck) is one of the 20 Secretary of State mechanic certification tests. Here's what the test covers, according to the state's published outline, along with practice built to match it.

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Practice Electrical Systems

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Topic drills (pass required)

Electrical fundamentals 25%Testing equipment usage 16%Starting and charging system diagnosis 19%Circuit diagnosis 20%Electrical diagrams 20%
Get the Electrical Systems passGet the All-Mechanic pass

Review status: These are original questions written to the official SOS topic outline. An independent review by a Michigan-certified mechanic is in progress. Spot an error? Use “Report this question” on any item.

What's on the test

Official topicWeightIn our mock
Electrical fundamentals
  • High voltage safety
  • Supplemental inflatable restraint (SIR)
  • Basic electrical
  • Series circuit diagnosis
  • Relay operation
  • Circuit protection devices
  • Networking and communication
25%14
Testing equipment usage
  • Ohmmeter usage
  • Voltmeter usage
  • Ammeter usage
  • Voltage drop
  • High voltage systems
16%9
Starting and charging system diagnosis
  • Batteries
  • Starter diagnosis
  • Starter current draw
  • Starter circuit diagnosis
  • Generator / alternator diagnosis
  • Charging system output
  • Charging system circuit diagnosis
  • Voltage drop tests
19%10
Circuit diagnosis
  • Short to ground
  • High resistance / open circuit
  • Blower motor circuit diagnosis
  • Lighting circuits
  • Cooling fan circuit
  • Warning circuits
  • Accessory circuits
20%11
Electrical diagrams
  • Electrical circuit recognition
  • Diagram usage
20%11

Source: SOS Mechanic Testing Categories Overview (PDF). Test format: most SOS mechanic tests have 55 questions, and a few have 65–100 (SOS FAQ). Passing scores vary by test; your result letter shows the passing score and your score.

Test-day facts

Source: michigan.gov/sos mechanic testing

Electrical Systems test FAQ

How many questions are on the Michigan Electrical Systems test?

The Secretary of State says most mechanic tests have 55 questions and a few have 65 to 100. The test is “quick pass,” so it ends as soon as you reach the minimum passing score. Our mock exam uses 55 questions in the official topic mix.

What topics are on the Electrical Systems test?

The SOS Mechanic Testing Categories Overview lists: Electrical fundamentals (25%), Testing equipment usage (16%), Starting and charging system diagnosis (19%), Circuit diagnosis (20%), Electrical diagrams (20%).

How much does the test cost, and where do I take it?

Each mechanic test costs $18 (effective July 1, 2026). Tests are taken on a touch-screen kiosk at any Secretary of State office; pre-register and schedule through SOS Online Services. Approved automotive schools can also test their students.

Do I have to recertify in Electrical Systems?

Yes. The SOS requires automobile and light truck mechanics certified in Engine Tune-Up/Performance, Electrical Systems, or Brakes and Braking Systems to recertify every five years by passing the latest state test, showing current ASE certification, or completing a state-approved training program. The Electrical Systems schedule lists a most recent recertification year of 2024, then 2029, 2034, and 2039.

Are these the real test questions?

No. MI Trade Prep questions are original practice items written to the official topic outline. They are not actual exam questions, and MI Trade Prep is not affiliated with the Michigan Department of State.

Sources: SOS mechanic testing · SOS mechanics page · SOS mechanic FAQ · Our recertification guide