During a UK summer, we all take steps to protect ourselves and our cars from the heat—but what about your car key fob? While most modern key fobs are built to be durable, they are still delicate electronic devices that can be affected by extreme temperatures.
At Parker Auto Locksmiths, we often see an increase in car key-related issues during the warmer months. From unresponsive buttons to complete fob failure, heat exposure is a common but preventable cause. In this blog, we explain how high temperatures affect car key fobs, what signs to look out for, and how you can keep your key working reliably all summer long.
Do High Temperatures Really Affect Car Key Fobs?
Yes, they can—especially during prolonged or repeated exposure.
While the UK doesn’t often experience extreme heatwaves, it’s not unusual for internal car temperatures to reach 45°C or higher on a hot summer day, particularly when parked in direct sunlight. Leaving your key fob on the dashboard, centre console, or inside the glove compartment can expose it to damaging levels of heat.
Even carrying your key in your pocket during a long walk or while working outside can cause the internal components to overheat over time.
What Parts of the Key Fob Are at Risk?
A car key fob might feel tough, but its electronic circuit board, battery and casing are sensitive to heat.
Here’s how each can be affected:
Battery Degradation
The small lithium coin cell batteries inside most fobs are designed to operate within a narrow temperature range. High heat can:
- Shorten battery lifespan
- Cause swelling or leakage
- Result in weaker signal transmission to your car
Circuit Board Damage
Prolonged exposure to heat can:
- Warp the PCB (Printed Circuit Board)
- Damage microchips
- Break soldered connections
Even mild damage can result in intermittent faults that make the key unreliable—especially when trying to unlock or start the car.
Plastic Casing and Buttons
The plastic shell of your key fob can soften, warp, or crack when exposed to heat, which may cause:
- Sticky or unresponsive buttons
- Gaps in the casing that allow dust or moisture in
- A key that no longer fits into ignition slots properly (for older manual types)
Signs Your Car Key Fob Might Be Heat Damaged
If you’ve left your key in the sun and it starts behaving strangely, heat could be the culprit. Look out for:
- Intermittent failure to unlock the car remotely
- Shortened battery life despite recent replacement
- Buttons that stick or fail to press properly
- Cracked or warped casing
- Fob works only when held very close to the vehicle
- Car fails to start if using a push-button ignition system
If you notice any of these symptoms—particularly after a warm day—it’s best to get your fob checked and tested by a qualified auto locksmith.
What To Do If Your Car Key Fob Stops Working in Summer
Step 1: Check and Replace the Battery
The battery is the most common point of failure. If the fob is otherwise undamaged but unresponsive, try replacing the battery with a fresh, high-quality one—preferably a reputable brand.
Step 2: Try the Manual Key (if applicable)
Most modern fobs have a hidden manual key blade tucked inside. This can allow you to unlock the door if the electronics have failed.
Step 3: Call a Professional Auto Locksmith
If changing the battery doesn’t help or if the fob is visibly damaged, contact a trusted auto locksmith like Parker Auto Locksmiths. We can:
- Diagnose and test your key’s circuitry
- Repair minor heat damage
- Reprogram or clone a replacement key if needed
We offer mobile services and can often assist on the same day, wherever you’re stranded.
Top Summer Tips for Protecting Your Car Key Fob
Preventing heat-related damage is straightforward once you know what to avoid. Here’s what we recommend:
Avoid Leaving Keys in Hot Cars
Never leave your fob inside the vehicle, especially not on the dashboard, seat or centre console. The interior heats up rapidly, even in mild weather.
Store Keys in the Shade
If you’re outdoors, keep your keys in a shaded bag, pocket or cool box. A zipped inside bag or heat-reflective pouch is ideal when at the beach or park.
Use a Key Fob Cover
Silicone or leather key fob covers add an extra layer of insulation, helping to shield the electronics from sudden temperature changes and sun exposure.
Don’t Leave Keys on Window Sills or Radiators
Even at home, avoid resting your keys in places that can heat up, such as sunny window sills or next to radiators and kitchen appliances.
Have a Spare Key Ready
Always have a spare key fob kept somewhere safe. If your main fob fails due to heat or wear and tear, you’ll have a backup ready to use while repairs are arranged.
Can You Still Drive If Your Fob Is Heat Damaged?
That depends on the extent of the damage and the vehicle make and model.
- If you have a manual ignition key built into your fob, you may still be able to start the car.
- Push-button start systems may not recognise the fob if the signal has weakened or stopped.
- Some vehicles will not operate at all without a working transponder signal.
In any case, it’s best not to risk being stranded—if your fob shows signs of heat damage, get it checked as soon as possible.
Why Choose Parker Auto Locksmiths?
At Parker Auto Locksmiths, we specialise in:
- Diagnosing and repairing car key fob issues
- Replacing lost or damaged keys
- Reprogramming or cloning modern smart keys
- Same-day mobile response across
All work is carried out by trained, fully insured technicians using professional equipment. Whether your key is playing up after a day in the sun or has completely failed, we’ll get you back on the road quickly and affordably.
Final Thoughts
It’s easy to forget how vulnerable your car key fob can be to heat—until it stops working when you need it most. But with a few smart habits and a bit of care, you can keep your key in top condition all summer long.
If you think your car key fob has been damaged by heat or if it’s started acting up after a hot day, get in touch with Parker Auto Locksmiths today. We’re here to help with expert advice, fast callouts and dependable service across the region.