Every time i put my 97 Ram into reverse the fuse blows! Has anyone had this problem before. The motor and trans are not original, bulbs are good, but it does have a factory tow package with a hitch.

Any ideas, or where do i start looking?

 

Disconnect the trailer harness, see if that doesn't fix it.

 

Is the wiring stock? Something is drawing more power than the fuse can handle. A short maybe? What else besides the reverse lights are connected to that fuse? The only thing I could suggest is to follow the wires and check for any problems.

 

trailer wiring.
the 7 way trailer connector has a pin for the backup lights. center one maybe? your backup light is shorted to ground somewhere in the harness or the connector.
even if you don't have the 7 way, the previous owner may have done something creative. my previous owner put the reverse lights on the ground pin of the 4 way...

 

I'll third the trailer wiring. Untill I replaced the plug on my truck and trailer with a new one, my reverse light fuse would blow every time I backed up with my trailer on.