Peterbilt 330/335/337 Heat & AC Parts

Frequently Asked Questions About Peterbilt 330/335/337 Heat & AC Parts

Will these HVAC parts fit my specific Peterbilt 330, 335, or 337 model year?

Most heat and AC components for Peterbilt 330, 335, and 337 models are compatible across years 2005-2021, as these trucks share the same cab design. However, there are some variations: pre-2008 models may have different blower motor connectors, and 2014+ models feature updated evaporator designs. Always check the specific part number against your OEM or contact our support team with your truck's year and OEM for guaranteed compatibility.

What are the most common signs that my heater core or AC evaporator needs replacement?

Key indicators include: sweet antifreeze smell inside the cab (heater core leak), foggy windshield that won't clear, wet passenger floor mat, reduced heating or cooling performance, and visible coolant drops under the dash. For AC evaporators, watch for musty odors, weak airflow, or the AC cycling on and off frequently. These symptoms typically appear around 150,000-200,000 miles on these models.

Can I install these HVAC parts myself, or do I need special tools?

While experienced mechanics can handle most installations, heater core and evaporator replacements require dashboard removal, which takes 4-6 hours. You'll need basic hand tools, trim removal tools, and ideally an AC recovery machine for evaporator work. Blower motors and resistors are more DIY-friendly, typically requiring only 30-45 minutes and basic tools. Many customers report the dash removal process is complex due to hidden fasteners behind the instrument cluster.

Are aftermarket HVAC parts reliable compared to OEM for these Peterbilt models?

Quality aftermarket brands like Red Dot, Bergstrom, and Four Seasons offer comparable performance to OEM at 40-60% less cost. These parts typically carry 1-2 year warranties and use the same aluminum core construction as original equipment. However, some aftermarket blower motors may be slightly louder than OEM. For critical components like compressors, many operators prefer OEM or remanufactured OEM to ensure longevity.

Why is my new blower motor still not working after installation?

The most common issue is a failed blower motor resistor, which often burns out when the original motor fails. Always replace both components together. Other culprits include blown fuses (check both under-dash and under-hood fuse boxes), faulty HVAC control modules (especially on 2008-2013 models), or damaged wiring harnesses near the firewall. Test with a multimeter to ensure 12V is reaching the motor connector before assuming the new part is defective.