When we think of summer problems for our cars, we often imagine overheating engines, low coolant, or air-conditioning failures. But one area that often gets overlooked is your car or van keys. With modern vehicles relying heavily on electronic key fobs and transponders, the hot weather can cause problems you might not expect.
At Key to My Car, we’ve seen first-hand how heatwaves across the UK—especially here in North Devon—can lead to unexpected key failures, lock issues, and frustrated drivers.
- Heat and Electronics Don’t Mix
Modern car keys aren’t just bits of metal. They’re small computers, packed with:
- Transponders to communicate with your vehicle’s immobiliser.
- Microchips for keyless entry systems.
- Buttons and batteries for remote locking.
When left in direct sunlight, such as on a dashboard, inside a glove box, or even in your pocket on a hot day, temperatures inside the car can soar well above 50°C. Prolonged exposure can:
- Damage delicate circuitry inside the fob.
- Cause solder connections to weaken.
- Shorten the lifespan of the internal battery.
- Warped or Bent Plastic Key Casings
Traditional keys may survive the heat, but the plastic casing around many modern fobs can warp if exposed to high temperatures over time. A warped case may:
- Make the buttons stick.
- Let dust or moisture in, further damaging the electronics.
- Prevent the key from fitting correctly into the ignition or slot.
- Key Battery Drain
Lithium coin cell batteries (commonly used in key fobs) don’t like extreme temperatures. Excessive heat can:
- Reduce their charge capacity.
- Lead to the key suddenly failing to unlock or start your car.
- Cause you to think your key is broken, when in fact it just needs a battery replacement.
- Metal Expansion and Locks
It’s not just the fobs—traditional metal keys can also be affected. Metal expands in heat, which might cause:
- Keys to feel stiffer in locks or ignitions.
- Older locks to jam or become difficult to turn.
This can be particularly problematic for vans and vehicles left in the sun all day on jobs or holidays.
- Water + Heat = Bigger Problems
Hot weather usually means beaches, pools, and outdoor activities. If your key gets wet—say, dropped in the sea at Woolacombe or splashed while paddleboarding at Croyde—the heat can worsen the damage by speeding up corrosion inside the key fob.
- How to Protect Your Car or Van Keys in Hot Weather
A few simple precautions can save you stress and money:
- Avoid leaving keys in direct sunlight (dashboard, window ledge, or on hot surfaces).
- Keep spare keys at home or with you, not in the vehicle.
- Store keys in a shaded bag or pocket when at the beach.
- Replace weak key fob batteries before they completely die.
- Replace wet keys immediately Once keys have got wet the PCBs and components corrode very quickly, especially if with salt water
Within the space of 20-30 minutes the corrosion can stop a key from permanently working . In some instances, without a working key and vehicle alarm active, it’s an expensive procedure to add a new key.
- What To Do If Your Key Fails This Summer
If your key suddenly stops working in the heat, don’t panic. At Key to My Car, we provide:
- Emergency mobile auto locksmith services across North Devon.
- Replacement and reprogramming of broken or water-damaged car and van keys.
- Fast roadside response to get you back on the road.
Whether you’re a local tradesperson relying on your van, or a family on holiday in North Devon, we’re here to help.
Call us on 07884 285570 for fast, professional help.
Final Thoughts
Hot weather is great for holidays and days out—but it’s not always friendly to your car keys. Taking a few preventative steps can keep your keys safe and working, but if the worst happens, remember that Key to My Car is just a phone call away.
