[ICOM] 706 Won't power up remote

[Al Waschka]

I am trying to install my 706 in a new (to me) 1999 F-150.  The radio has been out of the previous vehicle for about 6 months.  When I removed it it was working fine.  Since then I have changed the display in the front panel.  With the front panel on the radio and connected to a battery, but in the house, it works fine but I didn't try the remote cable.  In the F-150 I have the radio mounted under the front passenger seat, using the Icom mobile mount.  I have a temporary power cable which I plugged into the power outlet (not the cigarette lighter, but I have tried both) in the dash.  Using the same remote cable I was using in the other vehicle, the radio would not power up.  I then realized that I had not put the retaining screw in the radio end of the remote cable so I did that.  Now the radio powers up briefly and then shuts off, but I may not have been holding the power button down long enough.  If I remove the remote cable and put the
 front panel on the radio, it works fine with the temporary power cable plugged into the dash power outlet.  Any ideas why it won't stay powered up with the remote cable?
 
Thanks,
 
Al K5TAN