Locked doors and a dark screen are the winter 12V picture. The car looks bricked even though the high-voltage pack still has range. A jump wakes it. Here’s what to do.
What the picture looks like
The driver walks up to the car and presses the door handle. Nothing happens. The phone-as-key does not connect. The sentry mode lights are off. The headlights do not respond to the fob. The screen stays dark when the driver presses the brake.
The Tesla app, the FordPass app, the Chevy app, the Rivian app, and the Hyundai app all show the pack state if the cellular module is still alive. A pack at 50 percent with no response from the car is the most confusing case. The driver thinks the car is fine. It is not.
Why this happens in the cold
The 12V is a small battery that wakes the car. In cold weather, the 12V has less capacity. A 12V that works fine in summer can fail in January. The sentry mode and the phone-as-key both pull current from the 12V while the car sleeps. A weekend sit at a mall can drain a 12V past the wake threshold.
January in Chicagoland has averaged a high of 31.6F and a low of 18.8F. The polar vortex of January 2019 sat at -23F at O’Hare. The January 2024 cold snap hit about -10F at O’Hare. A car parked outside during those stretches loses range and 12V capacity.
What to try first
Walk through these in order before you call a local operator.
- Press the brake pedal and look for any dashboard glow. A faint glow means the pack is awake. A black dash means the 12V is dead.
- Try the app on your phone. If the app shows the pack state, the car is still reachable on the network and the 12V is still running the cellular module.
- Try the key card by holding it against the driver’s side B-pillar. The card reader works even when the 12V is flat. The car unlocks and the handles present.
- Try the mechanical key hidden in the fob. The fob has a small blade that opens the driver’s door manually. The alarm will sound until you put the fob inside.
What the operator does
The independent operator we connect you with brings a portable 12V booster matched to your EV. The operator clips onto the under-hood jump points or the hidden 12V terminals, lets the booster wake the 12V, and tries the start. The door handles present within seconds. The screen wakes. The DC-DC converter recharges the 12V from the high-voltage pack.
If the 12V is too far gone for a jump, the operator carries a replacement and swaps it on site. The operator quotes before any work starts and bills the driver directly. Charge Pro does not set the price.
If your EV has a dead 12V anywhere in Cook, DuPage, Lake, Will, Kane, or McHenry county, call (858) 925-5546. We connect you with an independent operator who can quote a 12V jump or replacement on site.