We all know that a dead car battery will not start your car. Even batteries with a low charge may not for long. If there is any charge in the battery, the engine will crank over. While there are many aspects as to why YOUR car will not start, like a human body, things are all connected and the culprit may surprise you.
In my case, my 2013 Honda Civic with 60K on it simply would not start. I mean, it was DOA, the only thing coming on were the interior lights, fan, radio. The battery was relatively new, so, what else would it be? The engine did not crank over, it was just DEAD!.
A Simple Inexpensive Fix
What I found out from others with similar symptoms was that your key turns an Ignition Switch that sends a small electrical impulse to the Start Relay Module. This signal then is boosted by the Main Relay and ignites the car starter and other components instantly that run your engine. I noticed that when I turned the ignition key a little, but not cranking over the engine, I heard a click sound. That click sound is telling you something is corrupt with the Start Relay Module, which is just a switch that opens or closes the starting circuit of your car. If that fails, nothing happens. It's as if your car battery is dead. The engine will never turn over no matter how many times you try- the circuit is broken.
Many of these modules are under the dash and are rectangular boxes, they are also in the main fuse box of your car. There are many multi-function relays in a car, so you must find where the Starter Relay is to be replaced (which simply pulls out). The part itself is usually less than $30.00.
After replacing this, if you still cannot start it, it could be the Main Relay, in my car, it is 50 Amp. Another thing to check is your Ignition Switch to see if it has malfunctioned. One problem to be aware of is parasitic draw from the battery due to having a circuit still connected even when the car engine is off and the key is out of the ignition. Overnight, it could drain your battery. If the relay is still allowing current to flow from the battery when the car is not being used, this leakage and drain from the battery could occur.
If you suspect the battery was drained by a malfunctioning relay, replace the relay and see if it starts. If the engine does not even crank over, charge the battery. Once started, drive it for at least 20+ minutes to charge the battery further. Now, a bad Alternator can also drain your battery due to the same kind leakage. A bad one will not recharge your car as you drive, it will just drain the battery dry.
If the car's problem was the Start Relay, you will save hundreds by doing it yourself in under 5 minutes rather than going to any auto repair place. If it is not that, it might be worth taking the car in.