RD218 and E120 Classic issues

I recently tried powering up my RD218 thru my E120 classic and when I hit the power switch on the E120 the softkey for scanner on/off appears but tx/standby does not. When I hit the on/off softkey it will not go to "on", just "off". I checked voltage at the +/- in the radar and it is 11.8 volts so likely not a power issue. Any suggestions?

Thanks in Advance,

Btrack