The Cadillac SRX uses 9006-style super-white headlights. These headlights are brighter than many other types of headlights, but eventually even these headlights will fail. When the filament inside the headlight finally breaks, you need to replace it with a replacement 9006 headlight available from any auto-parts store. When replacing the SRX’s headlights, be sure to replace both headlights because they will both have the same service usage on them. When one headlight fails, the other one is likely to fail shortly after.
Open the hood of your SRX and disconnect the power connector from the back of your headlight. Squeeze the tabs on the connector and pull the connector off the back of the headlight.