What To Do When Your Keys Get Wet, And Your Car Won’t Start?

Whether caught in the rain or simply dropped your key in a puddle or your soup bowl, wet keys are no fun. Needless to say, it can be super frustrating when it follows up with your car not starting. And worse, what if you don’t have a spare? 

Don’t worry. If you act fast, you can still save your key. And this diagnosing guide can help you along the way.

my keys got wet and now my car won't start

Why Won’t Your Car Start When You Have a Wet Key?

Your car won’t start when you have a wet key because of the electrical connection. Almost all ignition systems in modern vehicles use an electric starter motor, triggered when you turn the key in the ignition. 

This sends electricity to the starter motor, which then turns over your engine. But if the key is wet, this current will be impaired because of the conductivity of water. 

It results in a short circuit, preventing a signal from reaching the engine control unit (ECU). Therefore, it won’t be able to trigger the starter motor, and your car won’t start.

Besides, when a circuit board is exposed to moisture, it can cause your key fob battery to run down and become inoperable. 

If the situation worsens, the battery may leak or even explode—causing significant damage.

How to Diagnose and Fix Wet Keys Causing Car to Not Start

When your key or fob is wet, drying it off is the most obvious course of action. However, depending on how long it was submerged in water and the severity of the damage, you may need to take additional steps. So be sure to follow these:

Wipe and Dry Your Key

The first step is to wipe down your wet key or fob with a soft cloth, and then use a hairdryer or other heat source to dry it out. 

To start, turn the fob over so that the button is facing down. Gently shake it to remove as much water as possible, then use a clean cloth to absorb and draw out any remaining moisture.

Once you’ve done this, leave the fob with the button side down for a few minutes to allow any trapped liquid to fully evaporate. 

The cloth should help absorb excess water while pulling out moisture hiding in hard-to-reach crevices.

When using a hairdryer, it’s important that you do this gently, as the aim is to evaporate any moisture that has accumulated on the key, not to force it deeper into hard-to-reach spots.

Open up the Key

Open up the Key
Open up the Key

Once you’ve done all that, there will likely be some residual water left inside the fob. Now it’s time to open up the key fob. 

Depending on the fob type, this may involve unscrewing a small Phillips head, Allen head, or Torx screws or prying it apart with a flathead screwdriver.

You can find instructions for opening many different kinds of keys on this YouTube playlist.

After opening the case, use a dry cloth to remove any remaining water from the case and circuit board. 

In addition, you can absorb any residual moisture by placing it in dry rice or using silica gel packets.

Also, it’s best to use a cotton swab dampened in 90% isopropyl alcohol to wipe away any unknowable impurities and allow the board to fully dry out.

Check the Battery


Before attempting to clean up any possible battery acid, be sure to inspect the battery and check if it is leaking. 

If it appears to be leaking, gently remove the battery and use a cotton swab dipped in distilled white vinegar to neutralize any potential acid from the affected areas.

As a safety measure, it’s wise to consider replacing your key fob’s battery if it has been submerged in water, in case it has been damaged. 

Once you’ve taken out the discarded battery, wipe and sanitize the circuit board’s connectors with isopropyl alcohol. 

Allow it to dry completely before installing the new one. This simple step can help prevent future issues.

See If Your Car Starts

After ensuring that the key fob is completely dry, it’s time to put it back together and give it a try. If all the buttons are working properly, you’re good to go. 

However, if only some of the buttons are functioning, you may need to disassemble the key fob again and clean the affected contacts more thoroughly. 

Resync the Key Fob

If the key fob still isn’t working, double-check if it needs to be reprogrammed after being inactive. Your car’s manual should provide a few simple steps to reprogram the key fob.

Sometimes, if you have a remote-start system, it may need to be programmed separately. Look for the instruction manual or consult your car dealership for more information.

Lastly, if the steps listed above do not help, it may be time to invest in a new key to get your car running again.

Frequently Asked Questions (FAQs)

If you have further queries regarding wet-key issues, here are some commonly asked questions and their answers to help you out.

Can A Wet Key Damage My Car’s Ignition System?

No, inserting a wet key into your car’s ignition should not damage it in any way. However, if the moisture stays in the ignition, it may corrode and damage some internal electrical components over time.

Is It Okay To Use A Hairdryer Or Heat Source To Dry A Wet Key?

It may be okay, so long as you’re careful and use a low heat setting. Too much heat can damage the parts inside the key fob, so it’s best to stick with using a cloth or letting the key fob air dry.

Can Water-Resistant Keys Be Submerged In Water?

No, even if your key is marked water-resistant when exposed to water for a long period, it can seep through any small cracks or openings in the key’s shell, causing an electrical short. 

How Can I Prevent My Key From Getting Wet In The First Place?

To protect your key from getting wet, always keep it in a waterproof case when not in use, and never leave it outside, particularly in areas exposed to humidity or rain. You can also keep it in a small zippered pouch inside the car, just to be sure.

How Much Does It Cost To Repair Or Replace A Wet Key?

Generally, the cost of repairing or replacing a wet key can range anywhere from a few dollars to several hundred, depending on the car’s make and model. It’s best to contact your car dealership for an accurate assessment. 


In the end, remember that following these steps does not guarantee your key fob will work since there may be severe internal damage from the initial water exposure.

Don’t get discouraged if the worst happens and the key fob is beyond repair. Instead, view it as a valuable learning experience. 

Although it may cost a few hundred dollars, you’ll know exactly what to do if you encounter a similar situation again.

Related Posts:

Similar Posts