CR104B Vehicle Electrical and Mechanical Systems Practice Test

To measure wiper arm force accurately, you want to isolate the arm and linkage from the blade’s load. The attached blade adds friction, blade tension, and wind resistance that vary with wipe state, age, and glass condition, which would distort the force reading. By removing the blade during the measurement, the test captures the true effort required by the arm and linkage to move, without those blade-induced variables. After the force measurement, you can reattach the blade for functional checks.