Sprinter vans are small, economical versions of the common conversion van used primarily for business purposes, either for transporting goods or materials to and from a worksite or directly to customers. While efficient, Sprinters, just like any other motorised vehicle, are occasionally prone to not starting. If your Sprinter van isn't starting despite your best efforts, chances are culprit is either electrical or mechanical; either way, some DIY solutions exist to help you ascertain and solve the problem.
Make sure the Sprinter is completely turned off and engage the parking brake for safety's sake; you may also want to chock the rear wheels as an extra precaution to keep the van in place. Once you have done this, pop open the bonnet of the van.
Sit in the driver's seat (or have a partner do so) and turn the key to engage the ignition; listen for any noises and note what you're both hearing and seeing. If there is a single clicking noise and the headlights won't come on when activated, you either have a dead battery or bad alternator.
Replace the battery with the exact same model and type as the current battery. These can be purchased at many big-box retail or auto speciality stores. Once you've replaced the battery, try again; if the result is the same, order a new alternator for the model and year of your Sprinter from an auto parts dealer. You should also replace all the spark plugs at once when changing either the battery or alternator to eliminate any problems.
Turn on the headlights, press down on the brake and turn the ignition. If the lights come on but the engine won't "turn over," chances are the starter has gone bad. You'll need to consult a parts dealer to help you find a compatible replacement starter for the van.
Turn the engine on once again and listen for the fuel pump to engage inside the gas tank. If you don't hear that audible noise, chances are the fuel pump is spent. Do not attempt to measure fuel pump pressure yourself; consult a knowledgeable mechanic who can diagnose and fix the problem using a threaded gauge that will match your Sprinter's system requirements.