98 i30

Q -What’s wrong / what parts need replacing below? I never did replace the FRESH/RECIRC ACTUATOR on this, now it looks like there is something else to fix:

Previously: turn on HVAC & AUTO = A/C air blowing out top dash vent

Recently: air only comes out floor (?) at system start, definitely no air from top vents. If press MODE to cycle through the modes, and stop at “dash vents” = i can hear the mode doors changing, and then the air blows out the top as normal again. Then Press AUTO = no change (still working as normal).

Failure seems correleated to amount of time since system was last operated (minutes vs hours parked)…like the mode doors are holding their previous position for only so long before they give it up, and then <something> doesnt have enough gumption to force the change back through UNTIL modes are manually cycled…

TIA

BrianA
Planet Houston

 

TTT...is this thing on?

after a week of sitting: I can no longer get air out of the top dash vents...”Mode” still moves Defrost On and the Off again but that’s about.

i need to run the debug procedure...but it seems I have another stepper motor out (in addition to the recirc door).

- “How many of these doors are there on the HVAC stack?”

Seems like since I’m already gonna be in there to replace two already I mightaswell do them all huh?

DISCLAIMER - I’ve had the replacement RECIRC motor on the shelf for -years-...

 

There are 3 motors total.

Do you know about the diagnostic mode? The FSM has the procedure to test everything.

 

Are the three model numbers of motors to replace already broken out somewhere?

i’ll start: the “Fresh/Recirc Actuator” (FSN term) is:

Part Number 27740-40U00
says “Actuator-Air” on the label

there are a GT of three motors total, correct?

meaning there are only two other Part Numbers to identify:

- Mode Control

- Temperature Blend

?

BrianA in Houston

 

I have a similar problem. Is the FSM posted here? If this were my car, I would just buy the FSM. I'm fixing it for my ex father in law so I don't want to buy the FSM for a single use.

 

Found one.

https://www.my4dsc.com/nissan-info/f...ervice-manual/

 

Any luck on the Mode Control motor? I can't find it online for the life of me. Temperature blend motors are all over the place but the mode motor isn't coming up. It makes me wonder if I'm using the wrong terms for it.