Clock only works when headlight switch is ON (heads or park lights). WTF

[86Woodgrain]

So the fancy digital quartz clock works but it only works when the headlights or park lights are on. It always restarts at 12:00 at that point too.

Does anyone have a clue as to why that would be? Is the clock somehow wired wrong?? I don't notice any other electrical gremlins with the dash.

[atmafox]

Happens on mine as well.  Seems like it's not getting constant 12V, only dash illumination.  Haven't gotten to dig into this part yet but suspect there's something loose or disconnected back there.

[Freeagle]

Sounds like somebody crossed the wires for the clock power and the clock illumination.

[AMC of Houston]

The clock circuit is weird on the '79-up AMC's.  The main clock feed is via the 10A clock/dome light fuse.  However, the main feed when the lights are on is via the tail light circuit (its not just a dimmer circuit triggered by the lights).  So, if your dome lights are also not working, check that fuse.

Note there was an AMC TSB issued back then due to rampant misdiagnosis and too many good clocks being replaced under warranty, when the issue was just a popped fuse!

[86Woodgrain]

My dome light works.

[86Woodgrain]

FYI just an update in case anyone experiences the same issue.

I fixed mine by replacing it with the one from my parts car. I didn't need to change any wiring or anything, I just swapped it and it works like it should. So the clock itself was defective internally somehow.