All interior lights go off when turning on headlights

[Quakecom]

Hi guys,

when turning on my headlights this morning, I noticed that all interior lights that usually go on with it (instrument cluster, radio, AC control and message center) wouldnt light up. When the headlights are off, radio display, AC control and message center light up fine. Since this seems to be a systematic failure because none of the lights work with headlights on, I am thinking a fuse might be the cause for this. Anybody know what fuse I should be checking for? Or should I check something totally different?

Thanks for any help.

Quakecom

 

[Turdle]

what happens when you adjust the dimmer wheel?

 

[Quakecom]

what happens when you adjust the dimmer wheel?

Nothing happens. Lights stay off.

 

[JHC's Explorer]

It is most likely to be in the dimmer switch circuit or the dimmer switch itself. When you turn your main light switch to "park" or "headlights", the lights you mentioned will be powered thru the dimmer switch to whatever voltage the dimmer switch is set. Turning the headlight switch to off causes the lights to be fed the full system voltage (12v nominal) thru a different circuit controlled by the position of the ignition switch. I wouldn't rule out the possibilty that the headlight switch itself is malfunctioning, since it is responsible for determining which circuit is active.

 

[Snowy]

Mine did the same thing about 3 weeks ago. I stripped the dash and checked voltages (I'm an electrician) and found I had input to the dimmer but no output. I put a new dimmer on my mental "to do" list and bought a map light that I point towards the dash to see the instruments in the mean time.