@mercedes12,
First of all, did you purchase your PM from 3DR or is it a clone?
If it is a clone, many of the clones are not a complete PM and will not power the APM so we cannot help you here.
Also, is your APM a genuine 3DR product or a clone?
Regards,
TCIII GM
@mercedes12,
A genuine 3DR APM2.5 says “Ardupilot” on the case and not “Arducopter”. I suspect that you have clone parts. Who did you purchase your APM/PM from? If they are clones, I suggest that you refer to the seller who sold them to you or the manufacturer of the clone parts.
TCIII GM