ELECTRICAL DIAGNOSIS — Toronto, Etobicoke & GTA
Battery Keeps Dying?
Dead after sitting a few days, or a new battery going flat? We test the battery and charging system, measure the drain and trace it to the circuit at fault.
321 Rexdale Blvd #4, Etobicoke, ON M9W 1R8
Mon–Fri 8am–5pm · (416) 742-4521
⚡ Servicing your car at an independent shop does not void your vehicle warranty — protected under Canadian consumer protection law.
By the Radman Auto Repair team, independent auto repair in Etobicoke since 1999 · Updated October 2026
A car that is dead every few mornings, or a new battery that keeps going flat, usually has something drawing power while it is parked, a charging problem or a bad connection. Throwing batteries at it does not fix it. Radman Auto Repair tests the battery and charging system, then measures the draw and traces it circuit by circuit in Etobicoke.
Quick answer: if a healthy or new battery keeps dying, the cause is a parasitic drain, the charging system, a poor connection or short trips. We test all four before replacing anything.
At a glance
- Common drains: aftermarket remote starters, dash cams, alarms, lights staying on, modules not sleeping
- Also check: alternator output, battery cables and grounds, battery age
- Normal draw: a few tens of milliamps once the car is asleep
- How we find it: sleep-mode current test, then circuit-by-circuit tracing
- Pricing: call (416) 742-4521 for a quote
Common Causes of Battery Drain
Aftermarket electronics remote starters, alarms, dash cams with parking mode and amplifiers wired without a cut-off.
Modules not sleeping an infotainment, body or telematics module that stays awake after you lock the car.
Lights left on glovebox, trunk, vanity or underhood lights with a stuck switch.
Stuck relay a relay that keeps a fan, pump or heater running.
Charging system a weak alternator or a leaking diode that drains the battery when the car is off.
Battery and connections an old battery that cannot hold a charge, or corroded cables and grounds.
Signs of an Electrical Drain
- The car is fine if driven daily but dead after sitting two or three days.
- A new battery goes flat within weeks.
- Clicking or a slow crank after the car has been parked.
- A light, fan or radio that stays on after you lock the car.
- Electrical faults that appeared after an accessory was installed.
How We Trace a Battery Drain
- Test the battery state of health and a load test, so we know it can hold a charge.
- Test the charging system alternator output and diode leakage.
- Let the car go to sleep then measure the draw with the right meter, without waking the modules.
- Trace the circuit by measuring across fuses rather than pulling them, which wakes the car up.
- Find the component and repair the wiring, switch, relay, module or accessory at fault.
- Confirm measure the draw again so the fix is proven.
Car not starting right now? See car won’t start or just clicking. Battery light on while driving? See battery light & alternator diagnosis. Tesla 12V warnings? See Tesla 12V battery replacement.
Frequently Asked Questions
What is a parasitic battery drain?
A circuit that keeps drawing power after the car is switched off and locked. Every car draws a little to keep its memory and alarm alive; a fault that draws more will flatten the battery in days.
How much battery drain is normal?
Once all the modules have gone to sleep, which can take several minutes up to an hour on some cars, a typical draw is a few tens of milliamps. Much more than that will drain a battery over a few days.
Why does my new battery keep dying?
If a new battery goes flat, the battery was not the problem: look for a parasitic drain, a charging system fault, a poor connection, or short trips that never recharge it, especially in winter.
Can a dash cam or remote starter drain my battery?
Yes. Hard-wired dash cams with parking mode, aftermarket remote starters and alarms are common causes, particularly when installed without a low-voltage cut-off.
Can short trips drain the battery?
Yes. Starting the engine takes a lot of energy, and a few minutes of driving in the cold with lights, heaters and defrosters on does not put it back. A battery that only does short winter trips slowly runs down.
Will having the work done at an independent shop affect my warranty?
No. Using an independent shop for maintenance and repairs does not void your new-vehicle warranty. Keep your invoices; we document the parts and work on every job.
Toronto & Etobicoke’s Electrical Specialists
Radman Auto Repair has traced GTA electrical faults since 1999. We measure, trace and prove the fix instead of selling another battery.
This Service Includes
✓ Battery health & load test
✓ Alternator & diode test
✓ Sleep-mode draw measurement
✓ Circuit-by-circuit tracing