Parts for your 2007 Toyota Highlander-Tx valve

2007 Toyota Highlander TX-valve: what it does, where it lives, and when to replace it

Based on Toyota’s factory Repair Manual for Air Conditioning, the Toyota Electronic Parts Catalogue (EPC), and Denso component listings, the 2007 Toyota Highlander is fitted with a thermal expansion valve (TX-valve), sometimes called a cooler expansion valve. It’s mounted at the evaporator inside the HVAC case. On vehicles equipped with rear air-conditioning, there’s a second TX-valve at the rear evaporator as well. So yes—this model uses a TX-valve, and it’s a key part of how the A/C keeps cabin temps comfortable.

The TX-valve meters how much refrigerant enters the evaporator, reacting to temperature and pressure so the system maintains the right superheat. In real terms, that helps the Highlander cool quickly without icing the evaporator or wasting energy. When the valve sticks or drifts out of spec, they’ll often notice weak cooling at idle, wildly swinging vent temps, frosting on the valve/lines, or odd pressure readings during a gauge test.

As a rule, a TX-valve isn’t a routine service item, it’s replaced when there are symptoms or contamination. If a 2007 Highlander has inconsistent cooling, a competent A/C tech will verify charge level, condenser airflow, and compressor performance first. If the TX-valve is the culprit, replacement involves recovering refrigerant, removing the glovebox and HVAC case access, disconnecting the lines, swapping the valve, and fitting new O-rings. Whenever the system is opened, it’s smart practice to replace the receiver/drier (or desiccant), add the correct amount of PAG oil for component loss, evacuate with a proper vacuum, and recharge with the specified R-134a quantity shown on the under-bonnet label.

For Highlanders with rear A/C, both TX-valves and the long rear lines deserve attention—leaks or internal debris can create confusing symptoms. If the compressor has failed, flushing appropriate lines and components, replacing the drier, and inspecting both TX-valves for debris will save headaches later. Use the correct oil type (Toyota/Denso ND-OIL 8 or equivalent PAG 46, as specified for the vehicle) and follow torque specs from the factory manual to avoid leaks or warped fittings.

There’s not much to “maintain” on a TX-valve beyond keeping the system clean and correctly charged, ensuring condenser fins are clear, and running the A/C periodically year-round. Do that, and the 2007 Highlander’s TX-valve will usually live a long, drama-free life.

• Fitted components: Front TX-valve standard, additional rear TX-valve on models with rear A/C.
• Tell-tales of trouble: erratic cooling, frosting at valve/lines, abnormal gauge readings, high or low superheat.
• Best practices: new O-rings, replace drier, correct oil balance, vacuum, and charge to the label.

Popular questions

Where is the TX-valve on a 2007 Toyota Highlander?
It sits at the front evaporator inside the HVAC case behind the dash, typically accessed via the passenger side after removing the glovebox and related trim. If the vehicle has rear A/C, the rear TX-valve is mounted near the rear evaporator in the quarter panel area, accessed from the interior trim.

What are common symptoms of a failing TX-valve on this model?
Owners often notice poor cooling at idle, sudden swings from cold to warm air, frosting on the evaporator lines or valve body, and odd pressure readings during diagnosis. A stuck-closed valve can cause low suction pressure and warm vents, a stuck-open valve can flood the evap, risking icing and reduced performance.

Do all 2007 Highlanders have two TX-valves?
No. Only those equipped with rear air-conditioning have a second TX-valve at the rear evaporator. Front A/C–only vehicles have a single TX-valve at the front evaporator.