What color are the switch wires for the tail lights and dimmer on a 1990ldsmobile cuttlass ceria sl

The tail lights work off the headlight switch, and there is a fuse for the tail lights. Make sure the fuse is good, first, a 15 amp (blue) fuse in the instrument panel fuse block. Then, you might have a bad headlight switch.
So you DO have dash lights, they just don't dim from the dimmer switch? In the wiring diagram, there is a green wire from a "tail light relay" (in the "Junction Block-Right Instrument Panel") that carries power to all the exterior lamps, as well as having a splice to the Instrument Panel Cluster (illum. bulbs), and to the lamp dimmer, and to the radio bulb.
To do any further testing, you would need a voltmeter or a test light, so you could chase down this power loss. Good luck.

could be the turn signal switch I would try testing that.

running lights are not controlled by the dash dimmer switch. the problem will be either in the light switch ( first position is running lights) wires to the switch or fuses

OMG. sounds like you have issues. One of the wires must have rubbed through to ground. Start by replacing the wires. Then put in a factory switch.

This is not necessarily your dimmer switch. Most manufacturers tie the dash lights to the tail lights so that it warns you in a visible way if your tail-lights are not working. It sounds more like you have a power supply problem unless working the dimmer switch actually causes or resolves the problem. Chances are you either have a shorting power wire, or a mostly broken wire that is only making an intermittent connection. If it was constant I'd suggest checking fuses but with an intermittent issue, The only way to really check this is to start tracing wires and testing power along them when it's not working. Wiring diagrams help a lot.

sounds like the dimmer switch is broken and not running the resistor, sounds like you need a new dimer switch or look in auto store for the stick on LED sport lights and put a couple to light gauges up. cheap solution.

All go out at once, first check fuses,then dimmer switch for dash lights, finally headlight switch. To check dimmer switch, pull connection off back, on harness with test light and headlight switch activated, 1 of the leads should have power, if so, use ohm meter on dimmer to make sure it has reading between 0 and some value, if no value, open, dimmer is bad, if there wasn't power then check headlight switch, there should be heavier gauge wire that powers switch and 1 for output to hi/lo switch, smaller gauge wires for tail lamps, dash lights, license plate lamps, parking lights. The color wires from dimmer would correspond to the same colored wires on headlamp switch, probe that connection on headlamp switch with switch engaged and see if you have power, if not replace switch, if so, check wire from switch to dimmer.Now if the lights slowly went from bright one day, to less bright some other day, to not working, then the bulbs are bad... good luck...

How are your dash lights? Usually dash lights and tail lights are on one circuit. The dimmer switch is also connected to both circuits. If there is a short in the dimmer switch, then either tail lights or dimmer switch could have problems.

I recommend checking your dimmer switch. A bad switch will cause tail lights not to work. As long as bulbs are good and headlight switch is working and wires are securely in place, then the dimmer switch or fuse is bad.

DId you just install something, if you install something like a radio, you probably or someone probably messes with a the illumination wire and too much power is going there, first find the wire, then change the fuse..........



Smooth Tyler