Any instructions for PIU auxiliary air conditioning (rear air/heat)

[KayGee]

I noticed some unusual functioning out of the rear air/heat and wasn't sure if it was normal or not.

For the most part, when I use the rear air at any cold setting or in the middle temp setting at any fan speed, it seems to blow all air out of the 2nd row and cargo area roof vents.

When I start transitioning to heat, things seem to get wonky - most lower fan speeds seem to come out of the roof vents, but full high transitions heat to a vent cutout in the rear driver side cargo area. Sometimes hot air will also come out of this area at lower speeds if I transition quickly from cold to hot and don't adjust fan speed, leaving no air coming from roof vents.

I may have missed it, but I didn't see any specifics about this in either the PIU or retail owners manuals. Does anyone know how the rear air/heat is supposed to function?

 

[peterk9]

I believe this is normal if I recall correctly. This was discussed in another thread quite a while ago.
I'm not sure if on high heat it is to protect the roof material/headliner or if it is to prevent hot air blowing directly on passengers or perhaps both.

Peter