Dash lights sometimes work and sometimes don't

The bulbs all have to be good for the flasher to work. The flasher is under the dash, driver side. When you turn on a blinker, do you hear it clicking under the dash. If the turn light is on , on the dash , but not flashing, then a bulb is probably bad on that side. Leave the blinker on and walk around the vehicle to check the lights. Flip the blinker to the other side and walk around the vehicle again checking lights. If all the lights are lit, but not blinking, then the flasher is most likely bad.

do the rest of the lights come on, like heater controls and radio display lights and you say sometimes, do they work at times and not? you listed this as a 1999 Chrysler LHS is this the correct model?

sometimes when one of your bulbs is out it does that to all off the start with your turn signal bulbs other wise its you regulater fuse located under the hood

The same thing happens on my 2003 Impala. I found that my dimmer switch has an intermittent failure where sometimes the dash lights go out even with the headlights on.
If I wiggle the dimmer just right, the dash, radio, steering wheel, door locks, and every other light comes on (when the headlights are on). My fix was to mount my Garmin on the steering column in front of the speedometer so when the lights go out I know how fast I'm going. A replacement dimmer (or bypassing the current one and adding a resistor) should take care of it.

Lights and electrical circuits are sometimes in pairs so that you notice something is wrong (tail lights and dash). On a '90 merc grand marq., that would be fuse #4,the 15 amp blue one, in the panel next to your left foot. If you are lucky,it
just failed from age. If you are not lucky, there is a short in the system containing
the dash, tail,parking,side marker, license lamps and trailer tow relay if equiped.I had to replace the push/pull main light switch which was shorted. If you are lucky, just replacing the fuse in the panel will do it. Referance Grand Marquis Owners Manual for fuses and function.

This can happen when the wires to the lights come loose. If you know someone who can get in the back and check the wiring, and can hook them back up, that's probably all it is. Sometimes items in the trunk, or the back of an SUV, or just hard road bumps can shake the connections loose.

i would like to ask that only the dash gauges sometimes work and sometimes not .and Did the problem come on suddenly or was some previous action or work done......

These bulbs last a long time and if they'er all out you might find the running lights ( taillights arn't working too. ( blown fuse) the panel lights are on a separte fuse but they run off of the tailight fuse. the tailights are really all the lights that come on with the headlight switch except the headlights themselfs. Then that circuit entergizes the panel lights thea light the dash gauges the door panels switches the any console lights the car can have. the dome circuit is another fuse that lights the floor and dome ( if their is one) and any landou lights (piller)
sometimes this fuse is removed or blow and the dash lights don't work, Or sometimes just a few. The cluster can be removed but not all of the bulbs can be bought at the parts store as the lights are to be replaced by rebuilding the cluster and can't be serviced. Agin some of the door switches are made this way also and you have to replace the switch to get a good light in them.

are the signal lights working if so don`t worry about it as sometimes the manufacture has tried to make the interior so quiet sometimes you don`t hear anything.

i had to disconnect the battery and reconnect on my daughters car and that solved her problem, worth a try!