Skip the auto shop - Our mechanics make house calls

Q: Car won't unlock electronically, nor mechanically.

asked by on

The car had a actuator issue which got fixed and a new battery right before the actuator was fixed. None of the lights were on and it worked perfectly the day before. The car sat overnight outside, which it normally does, when i went to unlock it this morning, it would not open with the key fob, which had a full battery, nor the key. The car would not even beep as it normally does when you try to unlock it, nor was the security light blinking. When the key was in the door, there was no unlocking the doors, nor was there beeping either. you could still feel where the contact/point of where the door would lock and unlock though. It did rain pretty hard the night before so I'm wondering, could water of gotten into the ECU or fuses and wiped the electronics or something? Wiring in the door was fine and done while battery was unplugged, and car worked less than 6 hours before I tried this. Thanks for the help.

My car has 176776 miles.
My car has an automatic transmission.

Hi there. What seem to have happen is the battery went dead over night. If there was no sign of power, then the battery drained with a parasitic load overnight. The ECM and the fuses are protected to keep water out of them during driving conditions of any kind of weather. If you cannot get the doors to unlock, then take jumper cables and hook them up to the starter power cable and place the other cable on the frame of the vehicle and put the other cables on another vehicle for a few seconds to unlock the doors. Once the doors are unlocked, then open the hood and get a digital volt meter and check the power on the battery. Charge the battery to a full charge of 12.6 volts if the battery was very low. Then remove the negative battery cable (-) and put the volt meter leads on the negative cable and the negative post. Check to see if there is a voltage draw. If there is a voltage draw, then with the key off, operate all of the switches in the vehicle until the battery voltage drops to zero or near zero. Then that component needs replaced to keep the battery from draining again. I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose a parasitic load.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Car won't unlock electronically, nor mechanically.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Broken battery cable

Hello. It is common for the battery cables to break on this vehicle. Due to the location of the battery, there is not much give in the cable so over time vibration can cause the cable to break. If there...

Q: Car won't start, battery drain - 1979 Mercedes-Benz 450SL

Hello. The Chilton manual will be able to give you accurate information as to the location of the voltage regulator. This manual can tell you whether your voltage regulator is an internal or external part. It is not recommended that...

Q: Where is the transmission fluid dipstick located on my 2017 Toyota Prado

Hello. Yout Toyota does not have a dip stick. Your vehicle is designed with a fill plug located in the transmission pan. The only way to add fluid is with a transfer pump and the correct adapter for the transmission...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...