I just replaced my car’s radio. Why does my car not start over time?
Now my car won’t start.
The longer it sits, the harder it is to start.
Dead Battery — Check to see if the radio will work without having the key in the accessory or run position.
If it still works with no key in the ignition, then the ignition wire behind the radio has come into contact with the 12 volt battery wire also behind the radio.
We assume that when you say it won’t start, you mean that the battery dies slowly over time and that within some relatively short time, it is dead.
This is likely caused by a slowly leaking circuit. There may be a short circuit that is not blowing a fuse, but slowly allowing electricity to flow, thereby draining the battery.
There may be a small — almost invisible — contact point where a live wire is in contact with the chassis or other grounded metal.
Check all of the radio’s support frames for bare wires or even a braided wire with some few strands protruding, not insulated and touching the dashboard frame.
Also consider the radio itself. Is it a new or used radio? It could be defectively leaking electricity through the radio’s light or other circuit.