4L is recommended only in extreme conditions, such as deep snow, off-road mud or sand, or steep declines, according to the S-10's owner's manual. This setting sends maximum power to your front and rear axles, allowing you to gain extra traction. 4L should not be used for normal driving. However, there may come a time when you need to engage the four-wheel-drive system (4WD), and 4H doesn't provide enough traction. Shifting into 4L is different from shifting into 4H.
Bring your S-10 to a complete stop. Move the gear selector to "Neutral" and keep your foot on the brake (engine running). If your truck has a manual transmission, engage the clutch.
Press the "4LO" switch on the left side of the instrument cluster. This light will flash for a few moments.
Move the gear selector to "Drive" when the light stops flashing and remains steady. If your S-10 is equipped with a manual transmission, disengage the clutch.
Bring the S-10 to a stop again to switch back to 2HI (normal driving). Put the gear selector in "Neutral," apply the brake and engage the clutch (if applicable). Press the "2HI" button; wait for the light to remain steady before putting the S-10 back in gear.
