Tech-Info: Passenger compartment fan regulators

Passenger compartment fan regulators, commonly known as HVAC blower motor resistors, are located near the blower and operate as a series resistor for the blower motor. Read more about symptoms, causes of failure and much more.

VEMO | 30. July 2018 | Marten Bruhn

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TECH-INFO

Purpose

Passenger compartment fan regulators, commonly known as HVAC blower motor resistors, are located near the blower and operate as a series resistor for the blower motor. They regulate over several internal resistors or built-in electronics the current or voltage which controls the speed of the blower motor. If this function is not given, the passing of the next general inspection is impossible. The blower controller must function perfectly in at least three different speed levels.

Symptoms

Blower motor does not run smoothly
Windows remain foggy or iced
Blower motor is loud
Blower speed can no longer be regulated
Vibration due to moisture and resulting rust

Causes of failure

Internal short circuit in the blower motor
Overloaded engines due to humidity
Wear of the commutator ring, the slip ring or the carbon brushes

Consequential damages

Failure of the blower motor
F ailure of the entire air conditioning system
Charred connection cables caused by a short circuit

VEMO advantages

More than 200 Passenger Compartent Fan Regulators can be found on www.vierol-shop.de

Plug & Play for an easy installation
Material: PA 6.6 GF 30 / stainless aluminum
Also available as a practical repair set: passenger compartmen fan regulator and cable in one kit.

Regulator, passenger compartment fan