i have been looking for the same answer and connot find it. i have even tried asking Ford and they just beat around the bush about wanting to charge a $200 fee too diagnois the problem The fuse is under the hood. It is in a black box under the hood on the drivers side. You most likely will find a blue fuse blown. If the fuses are good you might have the same problem I had. I had a broken wire in the wiring bundle under the hood. The Ford garage found repaired it for around $150.00.
This information can be found in your owner's manual. You dont mention type of vehicle, but it is usually the "park"(or parking) fuse. Relentless
Many times the dash lights and tailights use the same fuse. If that does not work, check you headlight switch.
Which lights?
Check the park lamp fuse.
Answer 1 - Instrument Lights Operate IntermittentlyWithout doing a "hands on troubleshooting" of your vehicle, no one here can be certain of the specific location and cause of your problem. However, based on your question, I suspect that the cause is a loose connection in the circuit providing power to the instrument lights, or on the instrument panel circuit board itself.It is possible also, that the instrument panel dimmer switch is wearing out.Answer 2 -The dash dimmer switch or the headlight switch is the most likely problem.
CHECK THE FUSE PANEL DASH & TAIL LIGHTS WORK FROM SAME FUSE
The illumination lights are replaceable. You will need to remove the dash cluster to gain access to them.
The dash lights will dim when the head lights come on. Check for a dimmer switch on your dash. It allows you to adjust the dash lights so they are not too bright and affect your nighttime vision. It may be set too low.
Probably the dash fuse is blown, or the dimmer switch for the dash lights is bad!
Check your owner manual for fuse location and description. Probably just a bad fuse.
Check for a loose ground wire - sounds like lights are backfeeding searching for ground
Which lights?
check the Bulbs
check the fuse for dash lights
Dash lights may have problems coming on because there is a problem with the dash fuse. It is important to get a specialist to check the wiring and the fuse status.
a fuse or fulty wiring the brake lights are useually out the same time as the dash lights if that helps any
Check the dimmer setting for the dash lights. There should be a dial to adjust the brightness on the dash to the left of the steering wheel.
You may have a blown fuse.
the dash and radio lights are supposed to dim when the headlights come on. Make sure you have the brightness of the dash lights turned up as much as possible.