High-Low Switch Problems With Headlights

Headlight switches allow the driver to change between the high and low beams. The headlight switch receives power through the large wiring block behind it, and is protected from electrical surges by a fuse on the fuse panel. Replacement headlight switches can cost a hundred dollars for the part, but you can save yourself some money by diagnosing a problem with your headlight switch yourself.

Headlight Switch

A common source of issues with headlight switches is the contacts. The contacts connect the headlight switch wiring block to the headlight switch. The contacts can corrode, wear down or even break. Inspect the contacts on your headlight switch for discoloration. Scrub off discoloration with a pencil eraser and place dielectrical gel on the contacts to prevent future corrosion. Pull up on bent contacts with pliers. Worn contacts have to be replaced if they are not long enough to firmly reach the contacts from the wiring block.

Headlight Switch Wiring Block

The headlight switch wiring block may be the source of the issues you are having with your headlight switch, since the terminals on the wiring block can corrode just like the contacts on the headlight switch. The terminals can also melt the insulation covering them, causing shorts. Inspect the wiring block wiring for corrosion or shorts. Clean the wiring in the same way you cleaned the contacts on the headlight switch, and replace any wires that are frayed or have melted or are missing insulation.

Headlight Switch Fuse

A few fuses on the fuse panel operate on the headlight switch circuits to prevent surges of electricity from damaging the headlight switch. A fuse prevents a surge from reaching the headlight switch when a surge blows the fuse. But a blown fuse prevents electricity from reaching the headlight switch. For this reason, you should check the fuses that operate on your headlight switch circuits to see if any of them are blown. The location of the fuse panel varies by make and model of vehicle. Most fuses can be removed from the fuse panel by pulling them out of their slots.