If your 4th Gen Dodge Ram's A/C is blowing warm air, icing up, or you're noticing a sweet smell inside the cab, a failing A/C evaporator is likely the culprit. It's one of the more involved HVAC repairs on the 2009–2018 Ram 1500, 2500, and 3500 — but with the right parts and a methodical approach, it's absolutely DIY-able.
What Does the A/C Evaporator Do?
The evaporator is the cold side of your A/C system. Refrigerant flows through it and absorbs heat from the cabin air, cooling it before it blows through your vents. When the evaporator leaks or fails, your A/C loses its ability to cool effectively.
Symptoms of a Failing A/C Evaporator
- A/C blows warm or barely cool air
- Sweet or musty smell inside the cab (refrigerant or mold)
- A/C works intermittently or ices up and stops cooling
- Refrigerant loss with no visible external leak
- Oily residue near the HVAC box under the dash
Which Evaporator Do You Need?
The 4th Gen Ram uses two different evaporators depending on model year:
- 4th Gen Ram A/C Evaporator (2009–2011) – 68048899AA — fits Ram 1500/2500/3500 2009–2011
- 4th Gen Ram A/C Evaporator (2012–2022) – 68138270AB — fits Ram 1500/2500/3500 2012–2018
Parts to Have on Hand
While you have the HVAC box open, replace these at the same time to avoid going back in later:
- 4th Gen Ram A/C & Heater Unit Seal Kit (09–22) – 68048898AA — seals the HVAC box seams
- 4th Gen Ram A/C Line O-Ring (09–22) – 68046015AA — always replace when opening the system
- 4th Gen Ram A/C O-Ring (09–22) – 05161806AA
- Expansion valve — 2009–2013 – 68048896AB or 2012–2018 – 68138269AB
- A/C Temperature Probe (2007–2021) – 68004239AA — inspect and replace if corroded
Step-by-Step: A/C Evaporator Replacement
- Recover the refrigerant — this must be done by a certified technician with an A/C recovery machine before you open the system. Do not vent refrigerant to atmosphere.
- Disconnect the battery — safety first before any dash work.
- Remove the dashboard — the evaporator is deep inside the HVAC box. Full or partial dash removal is required depending on your trim level.
- Disconnect A/C lines at the firewall — cap them immediately to prevent moisture contamination.
- Remove the HVAC box — unbolt it from the firewall and lower it out from under the dash.
- Split the HVAC box — remove the screws along the seam to access the evaporator core inside.
- Remove the old evaporator — pull it out carefully. Inspect the expansion valve and temperature probe while you're in there.
- Install the new evaporator — seat it properly and replace all O-rings and seals before reassembly.
- Reassemble the HVAC box and reinstall — reverse the removal steps.
- Recharge the A/C system — have a technician evacuate, leak test, and recharge with the correct refrigerant amount.
- Test — verify cold air output and check for leaks.
While You're In There: Consider a Full HVAC Kit
Since you're already pulling the HVAC box, this is the perfect time to replace the blend doors too. Blend Door USA kits include CNC-machined aluminum doors that permanently fix the common blend door failure on 4th Gen Rams:
- 4th Gen Ram HVAC Repair Kit (09–19) Single Zone – Blend Door USA
- 4th Gen Ram HVAC Repair Kit (2009–2019) Dual Zone – Blend Door USA
Shop All 4th Gen Ram A/C Parts
Ram Parts USA stocks OEM-spec evaporators, expansion valves, O-rings, seal kits, and complete HVAC repair kits for the 4th Gen Ram. All parts ship fast from the US.