Standard Ignition RU-631 HVAC Blower Motor Resistor - Front or Rear

HVAC Blower Motor Resistor for GM Applications

Standard Ignition RU-631 is an HVAC blower motor resistor built for vehicles with automatic temperature control or automatic air conditioning, depending on application. It is engineered to address common resistor failures caused by water intrusion and excess heat, helping restore proper blower speed control in Chevrolet, GMC, Buick, Cadillac, Pontiac, Saab, Isuzu, and Oldsmobile models.

• Bolt-on attachment with a rectangular female connector
• 5-terminal blade design with included wiring harness
• 3-5 speed operation for multi-speed blower systems
• Upgraded water resistance with improved cover and perimeter sealing
• Enhanced heat dissipation through a larger-output power device and 2 oz. copper board
• Hardware and mounting brackets included
• Manufactured in the USA

Built for Reliable Blower Control

RU-631 uses an updated design that improves protection at the two most common failure points for blower resistors: moisture exposure and thermal overload. The sealed cover and RTV-treated perimeter help block water intrusion, while the heat sink and upgraded copper board improve conductivity and power dissipation. The included harness is voltage-drop tested to support proper electrical performance. This part cross-references Dorman OE Solutions 973-508 for the same application.

What It Helps Fix

• Blower motor stuck on one speed
• Intermittent HVAC fan operation
• No blower output at certain speed settings
• Resistor failure from heat damage
• Electrical issues caused by moisture intrusion at the module

Installation Notes

Fits 1999-2016 Chevrolet Impala, 2005-2009 Buick LaCrosse, and 2003-2006 Chevrolet Tahoe, with application-specific notes for automatic temperature control or automatic air conditioning. Fits 2003-2006 GMC Yukon, front, and 2003-2006 Cadillac Escalade, front, with automatic air conditioning. Review the vehicle’s HVAC system type and connector style before installation; some applications require automatic temperature control for proper installation. Standard Ignition RU-631 installs with a bolt-on mounting method and includes a wiring harness and mounting brackets.

Quality Assurance

Standard Ignition manufactures this part in the USA and validates the included harness through extensive voltage-drop testing. The upgraded resistor design is intended to improve durability by strengthening resistance to water intrusion and overheating.