02 Odyssey No air from 4 rear top vent

honda
odyssey
blower-motors
#1

I recently found out there is no air coming out of 4 rear AC vent on the roof (above head) in my 02 Honda Odyssey. I used both rear climate control knobs on the dash or in the back seat and also turned at different fan speeds. But, nothing happened. However, the return air (on the side panel at very back) flows just fine at various speeds.



Is the problem on rear transistor?



The front AC unit works just the fine (both hot and cold) though.



Thanks for any suggestion.

#2

Are you running air conditioning or heat? I believe the vents in the rear are only hooked up to an air conditioner. They are not hooked up to a heater. If you are running heat up front, don’t expect any to come out of those rear vents.

If you are trying to get heat out of the rear vents, you answered your own question when you called it a “rear AC.”

#3

I have a lot of mini van interior, and front and rear AC experience but I hesitated to answer your post because I did not understand two things, what does the phrase “Is the problem on rear transistor” mean and what do you mean when you refer to “the return air” flowing good.I know that vehicles with rear AC with or with out rear heat have a air intake at the rear unit (like a Suburban with it’s rear AC) are you talking about the air intake for the rear AC?

I had a customer with a Kia mini van that wanted heat out of the overhead vents,thats not how it goes just AC out of the overhead vents,heat comes from floor vents,car made it through the Advisor to me,just so I could tell them heat is never to come from the overhead, no charge.

You say no air flow at all,neither hot nor cold,there is a ducting network up a pillar and under the headliner.

#4

Sorry for getting confused by AC and Heat. I refer to the Climate Control system as AC.

I realized this problem only happens when I turn on Heat in the back. In '02 Odyssey, there is a knob on the dashboard next to the Climate Control System to control AC or Heat for the back seats. There are dials for low, mid and high fan speeds in Heat (red dots) or Cold (blue dots) or rear control.

When I turn it to Heat (red dots), no air comes out of the roof vents. But, the return air (on the side panel) flows just fine at various speeds. However, when I turn it to cold (blue dots), air comes out just fine at low, mid and high speed respectively.

“Whitey” suggested these vents are not hooked up to a heater. Is it possible? If so, why they have “heat” (red) dials on the knob?

To “oldschool”, I saw the air vents under the front rows seats. But, there is no air coming out either.

Thanks for valuable suggestions from both of you. I hope I explained the issue a little better this time.

Thanks all.

#5

They have a controllable knob so you can adjust the temperature of the conditioned air, much like you would do if you were running the A/C and heat at the same time up front to keep the windows from fogging in the winter. So maybe you can run heat in the back by having the air conditioning on at the same time, but din’t expect this to be heat from the engine. The rear air conditioner is actually a separate A/C unit usually in the back of the minivan. So it would be impossible to run heat from the engine through the rear vents. The rear A/C probably has some kind of electric heat to temper the conditioned air for comfort, but probably doesn’t heat the air as efficiently as the engine. The engine does such an efficient job of heating the car, an additional heater in the back shouldn’t really be necessary.

In any case, I don’t think anything is broken. Heat from the engine is so efficient and effective in warming the inside of the car, an additional heater in the back should not be necessary like A/C is in the summer.

#6

When I turn it to Heat (red dots), no air comes out of the roof vents. But, the return air (on the side panel) flows just fine at various speeds. However, when I turn it to cold (blue dots), air comes out just fine at low, mid and high speed respectively.

There should be no return air when you run the heat. Air should only be recirculated when you run the air conditioner. I believe what you think is recirculation is really heat coming out of vents on the dashboard that are designed to push hot air into the back.

The rear air conditioner is just that, an air conditioner. All heat will have to come from the front.

#7

Clarify what you call “return air” Can you feel this air being drawn in or can you feel it being blown out?

Where did you get the term “return air”? we know you have a predisposition to get terms mixed up.

The only problem I can see from the data you post is when you say you have no air (neither hot nor cold) comming from what are obvious air discharge nozzels “under the front row seats”.

Some vehicles do have a heater core in the rear(Venture min-van,Suburban for just two)