Dash lights go off when I switch head lights on.

[JohnnyMug]

Hi 

I have a problem with toyota corolla 2006 1.6 56 reg. When I switch the engine on dash lights are on like normal. But when I switch parking lights or headlights on its goes off cant even see the odometer. The MPG values seem to jump radically up and down too (not like they do usually just big ammounts at the time which seems odd). 

Anyone now why is this happening? 

[FROSTYBALLS]

Presumably one needs to adjust the dimmer for the instrument lighting.

From memory - with the sidelights or headlights on, press the dashboard button that toggles the odometer display until a series of dashes is displayed, and then press the button and keep it depressed until the instrument lighting is bright enough for you. Turn the sidelights/headlights off, and that should be it as regards the lighting.

Could try disconnecting the Battery for a while to see whether that resets the consumption display.

[JohnnyMug]

Thank you so much this helped I tried twisting the knob .... thought it was electrical problem. I only had my corolla 2 days still learning. Anyway case is closed thanks again!!!