Auto Electrical & Diagnostics in Janesville, WI

Expert Troubleshooting for Check Engine Lights, Batteries & Alternators

Today’s vehicles rely on complex electrical systems to power everything from your ignition to your infotainment. When something goes wrong—whether it’s a failed starter, dim headlights, or a stubborn check engine light—you need fast, accurate diagnostics and skilled repair.



At Centerway Auto Repair in Janesville, WI, our ASE-certified technicians specialize in auto electrical diagnostics, car battery replacement, and alternator repair. We use advanced tools to pinpoint issues quickly, and we never guess when it comes to your safety or your wallet.

A close up of a speedometer with a yellow engine light

Our Electrical & Diagnostic Services

Check Engine Light Diagnosis

A check engine light can mean anything from a loose gas cap to a serious engine misfire. We use professional-grade scan tools to read trouble codes, interpret what they mean, and recommend the right course of action—without unnecessary upselling.


Battery Testing & Replacement

Weak or dead batteries are one of the most common causes of breakdowns. We test your battery’s voltage and cold cranking amps, check for corrosion, and replace it with a high-quality option when needed. We also inspect charging and starting systems to prevent repeat failures.


Alternator & Starter Repair

If your vehicle won’t start or is losing electrical power while driving, the alternator or starter may be to blame. We test, repair, or replace these components to ensure your engine starts reliably and your electrical system stays charged.


Electrical System Diagnostics

Flickering lights, malfunctioning dashboard displays, and intermittent power issues are often signs of a deeper electrical fault. Our team performs thorough diagnostics to trace the root cause—whether it’s a wiring issue, a failing control module, or a short circuit.


Fuse & Relay Replacement

Blown fuses and faulty relays can knock out key systems like headlights, wipers, fuel pumps, and more. We test and replace only what’s necessary to restore safe operation.

Schedule Electrical Service in Janesville Today

If you need car battery replacement, alternator repair, or you're seeing a check engine light in Janesville, don’t wait for the issue to escalate. Contact Centerway Auto Repair today to schedule expert electrical diagnostics and service.


We’ll get your systems running smoothly and your vehicle back on the road—quickly and reliably.