[chuck16]

I would say try taking the photocell out and test it for continuity. Shine some light on it and it should be some resistance there and when it's dark it should be O/C

The only reason I believe this is; I've wired my photocell with an override switch. So, when I don't want the photocell to do it's job I close the circuit with a 1.5 K ohm resistor and when I want them in automatic I flick the switch to the open position.

Hope this helps your trouble shooting. It may be that your photocell is just there and somebody dropped the wiring off of it from below. Quick way to check is to pop the Stereo out and look at the bottom of the photocell from inside the dash.

Hope this helps.