OK. I went and checked my wiring for you guys.
There are two green wires that go to a lightbulb holder. One should be connected to the dash light circuit. The other is connected to ground
The four wires for the clock are as follows:
RED is for the always hot 12V (a battery feed that is not switched)
BLUE is for a switched 12V lead (you might be able to use the cigarette lighter wire for this.
GREEN is connected to a feed from the dash lights (the same as one of the green wires above). This wire is used to reduce the clock brightness when the headlights are on.
BLACK goes to ground.
In the connector, The red wire is by itself and should be connected to always 12V. The blue wire is by itself and should be connected to a switched 12V lead (ignition accessory switch). The black wire and one green wire are combined and they should be connected to ground. Two green wires are combined and they should be connected to one of the feeds to a dash light.
CB: your cigarette ligher plug won't work for two reasons: (1) the cigarette lighter is switched with the ignition switch. There is not always 12V to it. (2) the illumination light is set up to dim (one wire feeds the light 12V switched on when the headlights are on and the other lead goes to the dimmer switch). The inclinometer plug is not set up to dim (it would need to be a 5-connector plug to allow dimming).
HTH.
Regarding this part of your post: "Two green wires are combined and they should be connected to one of the feeds to a dash light."
Wouldn't this be dimmable(if that's even a word)and not work for the inclinometer clock like you stated?