hi all
bought a 1986 f150 base model. Did not have a clock in it.I got a oem clock but can't find a plug under the dash for it. Do I need a adapter?

 

It begins from C125 then to C125A in this diagram:
You may be missing the C125A cable?
http://img259.imageshack.us/img259/2417/ipwiring.jpg

If not there then you will need to hard-wire it in. 1 full time hot, 1 ignition switched hot, 1 to headlight circuit, and 1 ground.