2005 Mitsubishi Endeavor — Passenger Side HOT / Driver Side COLD — Blend Door Diagnosis?

Hey everyone,

I’m dealing with a temperature issue on my 2005 Mitsubishi Endeavor and I want to confirm my diagnosis before I drill into the HVAC box.
Well taken care of 114k 2nd owner family car bought new in 2005 service every 5k all factory service completed timing belt new at 90k. This car has been babied but was driven by my grandmother who barely drove 5k a year. Unknown how long heat has not worked as she did not drive in the cold and when she did trips were so short she would not have noticed it not getting hot.

Symptoms:

• Passenger side gets blazing hot
  
• Driver side blows ice cold air
  
• Happens in ALL modes:
  defrost / center vents / floor / rear floor
  
• When turning the temp **** to cold, the passenger side gets cold correctly
  
• Driver side NEVER gets warm, except slightly warmer on fan speed 1
  
• Hitting the recirculate button makes the driver side slightly warmer, but still far from hot
  
• Mode doors all work (defrost, face, floor all change correctly)
  

What I’ve already checked/tried:

• Heater core is flowing — passenger side heat is extremely hot, so it’s not clogged
  
• Blend door actuator on passenger side IS working/moving properly
  
• No separate driver-side blend actuator visible
  
• Removed dash panels and inspected from both sides
  
• Manually moving the actuator shaft on passenger side does NOT change driver side heat
  
• Driver side remains cold regardless of control settings
  
• Based on airflow behavior and known Endeavor issues, I believe the driver side portion of the blend door is broken internally
  

My question:

I’ve attached a photo with a red circle marking the spot on the front face of the HVAC box where I am planning to drill a small access hole. The goal is to insert a rod and manually push the broken driver-side blend flap into the full-heat position.

Is this the correct location to access the driver-side blend flap?
Has anyone here done the “drill and push” fix on an Endeavor or Montero with the same symptom pattern?

Just trying to confirm before I commit.

Thanks in advance!

The red Circle is the drill point the arrow is just for orientation purposes.

 

Looks very interersting situation, do you found the solution?
greetings

 

Not Yet. Just wearing layers and bringing blankets for the kids until i get it sorted.

 

Hi. You must hhave a garage to attempt all that disassembly.
Try looking at a 'replacement' part,and see if you can pinpoint the location. That might help.
I'm busy for a few hours,but I'll look at what repair manual stuff later..
Jeff