2003 Volvo V40FACTORY OEM SERVICE PROCEDURE

Wiper functions: Rheostat

The rheostat can control the light intensity in 16 steps, with a 12% to 100% activation cycle.

If the key is in position 2, the rheostat controls the light intensity of the instrument lighting in the passenger compartment.

  • combination instrument
  • heater instrument
  • radio

Central electronic module (CEM) reads off the thumb wheel's status (resistance) which is located beside the light switch, which then controls the light with an activation cycle.

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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