Heating Archives - UnderhoodService
HVAC Diagnostics

Knowing the cause of the complaint might require looking at several components.

Solving Intermittent Overheating

New cooling systems anticipate and influence changes in coolant temperature.

Solving No Heat Complaints

Here are 10 guidelines for making sure a customers heat functions.

Audi Tech Tip: Passenger Compartment Not Warming Up?

Code B10D004 will indicate a coolant circulation pump failure.

Tech Tip: Cold Temps Set DTC On Some GM Vehicles

Some GM customers may find that their vehicle’s malfunction indicator lamp (MIL) illuminates after starting the vehicle when using the engine coolant heater in very cold ambient temperatures.

Tech Tip: Mazda Leak From Rear Heater Pipe

During winter driving, especially in the 23 “Salt Belt” states, water containing salt may accumulate in the black plastic pipe cover and/or the brackets of the wheel housing. This may cause corrosion and perforation of the rear heater pipe, resulting in coolant seepage from the rear heater pipe.

Tech Tip: Honda Fit’s HVAC Blower Motor Works Only On High Speed

Applies To: 2009-’10 Fit – All 2011 Fit – From VIN JHMGE8…B5000001 through JHMGE8…B5000012 2011 Fit – From VIN JHMGE8…BC000001 through JHMGE8…BC012605 Symptom: The HVAC blower motor works only on high speed. Probable Cause: Excessive current draw from the HVAC blower motor causes the blower resistor to fail. Corrective Action: Replace the HVAC blower motor

Tech Tip: Toyota Highlander’s Heater Goes from Hot to Cold on its Own

A loose control knob potentiometer could cause erratic behavior on a Highlander climate control system.

Cadillac Ciel Concept Celebrates the Journey

The spacious and elegant concept car Ciel is powered by a twin-turbocharged version of the 3.6-liter Direct Injection V-6 engine, paired with a hybrid system using lithium-ion battery technology. The Ciel – pronounced “C-L,” the French translation for sky – is a four-seat convertible that opens a new chapter in Cadillac’s design and product ascent, pushing the brand’s Art & Science philosophy into a new stratum.

Tech Update: HVAC Diagnostics

Leave it to the OEMs to take a simple system like heating and air conditioning and turn it into an electronic jumble of wiring, sensors and computer components.

Tech Tip: Heater Core Electrolysis/Leakage

The majority of repeat heater core leaks are due to high flow rate or use of poor quality coolant. However, electrolysis should also be checked, especially when repeat repairs have occurred.

Tech Tip: Mazda Seat Heater Needs a Boost

Some Mazda6 drivers may complain that the seat warmers turn off too early or may not heat to their satisfaction. The operating temperature of the new seat warmer has been increased on later vehicles by 14 degrees F (on average) to address this concern.