HELP!! Random no start

[jlevie]

A battery at 12.4v is only at 75% charge. And if the battery is old it may not be able to deliver sufficient peak current to start engine.

Have the battery tested, of if more than 4 years old replace it. Also check to see if the alternator is working properly.

[offwhiteghost]

UPDATE:

[I don’t know if this is related but if I turn on my lights my radio will lose sound.

Any ideas?] + PO had an aftermarket alarm that was disabled.


So heres the deal,

I have an 89 325i auto with a random no start. It will start fine for 3 days then just wont but if i hook it up to a charger or jump it starts fine. Battery is fine and measures 12.4 volts even when it wont start. Both battery connectors replaced.

Could it be the starter relay and where is the relay located?

Please advise