The head lamps should not get dim. Dim light are an indication of low voltage. You should have a volt meter in the instrument panel. If the voltages is not reading about 14V when the engine is running, you have a bad battery or alternator. It should read over 12V with the engine not running and the ignition in the on position. It should not drop below about 9-10 when cranking the engine. If you have low voltage during cranking and normal voltage at other times, you probably need to replace the battery.
Check the ground wire to the brake lights.
probably because your dimmer switch is bad or a relay
1991 S10 BLAZER 4DR NEED WHEEL BASE DIM
2000 dodge ram wiring rear end tail ligts dim and right blinker works but very dim
Long Dim Road was created on 2000-04-18.
* Voltage Regulator * Defective Battery * Dirty Battery Post Connections * Alternator/Generator problems
The low beam lights should be set up as the outermost headlamps. All 4 will be on the when the "high beams" are switched on
You probably have a bad ground on your "dim" light.
Change dim dip resistor, or check connections for melting/corrosion Just had the same on my 306 apparently the resistor gets quite hot! Not sure on cost, got mine from scrapyard for nothing because they didnt know what it was!
Most likely the dimmer switch. I have had this problem before and I went to a pull a part junkyard and bought a few of them. I highly recommend doing this, as I have already blown 2/3. It's a common problem with our trucks.
Check your alternator it could be malfunctioning. Sometimes it gives you warnings like this.
because before they were not dim The heater could be drawing too much power or your alternator isn't producing enough.