[1950Mercury]

I purchased a re coned front 10 ohm speaker off evilbay. I noticed it only had a green wire. I thought that was strange but I installed it. I figure it is using a common ground. I see the radio has a plug with 3 provisions. Green which I know is a speaker wire black Which I presume is a ground and yellow which I know is power. So question being will the black wire from the radio plug need to go to a ground or with the radio and speaker mounted will they automatically ground through the dash?

[Cammer-6]

pic of connector on said speaker please

[1950Mercury]

Speaker is already in the car. I know it was not uncommon for older cars to only have 1 speaker wire especially with mono a/m radios. I just need to know if the black wire coming out of the radio needs to go to a ground or just let it hang. 66 GTO a/m radio. 1 yellow wire power a green speaker and then the black wire in question.

[Cammer-6]

normally theres a clip or fastener that bites in to metal that speaker is mounted to
that grounds it. A star washer under the nut will suffice.
No harm in grounding that black wire.

[gto4ben]

The '66-'67 front speaker is grounded to the body from the cone lead to the speaker frame & mounting braces as shown.

Similarly, when a rear speaker is ordered, it's also grounded from the cone lead to the speaker frame and then to the body with a tab that pokes through the paint when tightened as Cammer-6 said.

The radio is primarily grounded from below with the support bracket. The connector ground was not used to ground the speaker(s) as shown in the wiring schematic.

It's ok to let it hang provided the radio and speaker grounds are connected. Insulate the loose wire to prevent shorting to an exposed hot wire.

FYI, the rear speaker in '66 and earlier was a deep frame design. In '67, they had a shallow frame design. I suspect the design change was to allow a better midrange frequency response for the stereo tape player and for stereo radio.

Date code on speakers may be decoded from the 466XXX number. 4th digit is year and last two digits are the week.