Twilight Sentinel can`t be turned OFF (1979 De Ville Le Cabriolet)

[Le Cabriolet]

First of all: Is that an Issue? Yes ! Why? Because if you have a weak battery and / or starter the last thing you need is power being diverted to exterior illumination.

The sentinel does its job, switching on and off the lights as it should. But there is no way to stop it. Neither by turning on the manual light switch (e.g. to marker lights position) or by turning the sentinel switch to "off" position.

Also, moving the circular switch/dial (potentiometer) doesn`t change anything about the "coming home light" duration. It will go out after some ten seconds no matter where the dial is set. I assume these two conditions are connected.

Does anyone have ideas or hints? The shop manual does not cover this condition... 

(My car does not have the automatic headlight dimmer option.)

[bcroe]

My 79 Eldo had such a failure, it ran my battery dead one
night.  My cure was to remove the control module, which
now resides on a shelf with other failed controls.  Perhaps
replacements can be had.  good luck, Bruce Roe