Before you buy a new antenna, I'd suggest using a VOM plus the car's electrical manual (if you have it). I've been down this road (no pun intended) before and I've found wiring "jobs" done elsewhere in the car by a PO that eventually caused the antenna not to work - things like cutting into the wiring harness, splicing here and there, yuk! Better yet, apply 12 volts to the antenna (like from a power supply) and see what happens. You might save time and money and avoid having a second antenna you don't need.