Hoe do I fix a dim right headlight?

When you ran a test lead from the battery, did you run a separate ground wire to the bulb? If yes -- confirming no ground from the original lamp connection -- try inspecting the body ground closest to the lamp: Remove, clean w/ wire brush or steel wool (both the connector and the nut/bolt holding it to the body), then try again. If still no luck, check ALL the body grounds in the engine compartment. If there's still no ground, try using a "quick splice connector" to connect a grounded bypass cable to the original grounding cable, near the lamp. (These connectors can be tricky. Instructions say you don't need to strip the sheathing on the cables, but I usually cut the sheathing with a knife to make sure there's a good connection.)
Regarding HID lamps: for running lights, do the main headlights come on w/ reduced power, or is there a separate lamp? If it's a main headlight, maybe there's an issue w/ a step-down transformer, or whatever system is used to dim the lamp.

Check and see if your ground wire is grounding properly. I ran a new ground wire right from my engine and works good now. Some times the ground wire is affected by rust if it's grounded to the body itself.

You may have a loose or corroded headlight ground to the body, the ground wires are in most GM attached to the body near the headlight under the hood. Check all the grounds you can see on the inside of the fender, tighten and clean the with a wire brush, also check the headlight connector for problems like corrosion or not fully seated to the headlight bulb.

This is caused by a poor headlight ground to the body of the car, the ground is most often found near the headlight under the hood, just follow the connector wires to the headlight bulb back through the wiring harness to locate it.

You either have a very low battery or a bad ground circuit to your headlamps or high resistance in your positive voltage feed to the headlamps.

First check your battery and charging system. There should be 12.2 to 12.6 volts at the battery terminals with the engine off. If this is ok, start the engine and check again. The charging voltage at the battery terminals with the engine idling should be 13.6 to 14.4 volts. If this is ok, then the problem is not your charging system.

Next, unplug the connector at headlamp bulb. Check the voltage at the ORANGE wire and at the ORANGE/BLACK wire. The voltage here should be the same as your battery voltage +/- 0.3 volts. If this is good, then the problem is the headlamp socket connection to the bulbs, or it is on the ground side of the circuit and you will need wiring diagrams and a scanner to find the location of the problem. This side of the circuit is controlled by the body control computer and there are several components involved.

{: ) Looks like your lightings got haywired. Have you had vehicle repairs recently? Anyway, it seems that you have poor grounding connections for the affected lightings. Some circuits share common ground, and ground terminals are strategically distributed on the vehicle. If these grounds don't have good contact with the body, chassis, or engine ground, circuit functions are badly affected. Thats why these ground points should be inspected and kept clean and tight, maintain that good wire and terminal contacts.
We can start with G100 located at the Left Front of the Engine Compartment on the left front body mount. See diagram below:


Check out also G401 which is located in the chassis harness, mounted to the left rear Body mount. This ground point is shared by the rear lamps like the brakes, reverse, and rear signal lamps.
If possible check also other ground points that you may visually come across while on your search. Be sure also that fuses are all inspected good.
I hope we get lucky in finding and fixing a certain lamp function, if not all. Goodluck.

It's quite common for headlight connectors to become so tarnished that one or both of the filaments in the headlights is either dim or non-functional. One way to clean them up is to cut a strip of steel the same width as the terminal blades on the headlight (this is for push-on connectors; some vehicles use screw terminals) and long enough to hold conveniently, then cut a strip of Scotch-Brite about 6-8" long and the same width. Wrap and hold the Scotch-Brite around one end of the strip to make your contact cleaning device. Push it into the connector contact and pull it out several times. Repeat for each contact. Next, identify the ground wire for each headlight connector (black or green wire that connects to vehicle body metal somewhere nearby). Unscrew the ground terminal from the vehicle body and polish the terminal and the underside of the screw head, and clean the body metal in the area covered by the terminal.

If the headlight comes on but is still dim, repeat the connector cleaning procedure. If the headlight connector is very severely corroded, you may need to replace it.

When you replaced the headlight switch was there any melting on the connector to switch? if connector was good then take a look at the wiring to lights, check the ground connection at the body, you will need to follow the wiring back from the plug to locate the ground connection.

if the one headlight is dimmer than the other, it's most likely a grounding issue. Pull the headlight connector and follow the wires and find the one that is grounded to the body of the car. Make sure that the connection is tight, not cut or damaged, or corroded. You can cut out the damaged piece of wire and replace with a new one of similar size and color,

Hi,

A couple of suggestions:
1. Check/replace the bulbs;
2. Check/clean the connectors;
3. Check/clean/replace the fuse;
4. Check/clean headlight relays.

Often the problem that exhibits dim headlight is loose grounding. The three wires that leads to each headlight bulb would be for low, high and ground.m You need to trace the ground wire and determine if the other end is grounded properly. A quick fix is to add a grounding strap/wire to the appropriate wire/connector of each headlight bulb with the other end to the chassis/body of the vehicle.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

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