Toyota Repair Problems? Ask a Mechanic for Answers ASAP
Hello and good morning. Does any airflow occur at the rear vents?
Your JA Expert,
yes but not from all of the vents.
I have an 04 Sienna, so i know the vent positioning. Which vents do not have air flow?
It seems like air is only coming from the middle vent on the right side near the sliding door
Ok, let me take a look at the diagrams and see if one of the blend door motors can stop flow beyond that vent. I'll be right back.
ok, it seems like it just stopped flowing hot air all of the sudden.
I'm sorry I just went to confirm again. all of the vents in the rear seem to work correctly when you use the rear control. when using the front controls air only flows out the floor vent that is on the right side near the sliding door. it's actually not on the floor but on the side of the van up about 10" from the floor. However there is no heat from any rear vent though.
everything works good with the front controls as well as the heat itself. it gets plenty hot in the front. Is there more than one heater core?
There is an air-mix control blend door motor located at the right rear of the van near the blower motor. It is behind the plastic interior trim. The movement of that blend door motor needs to be confirmed. It is very possible that that motor has failed in a single position and not allowing airflow to make it everywhere. There are a few items involved in the control of the rear heating and airconditioning so that is where the inspection needs to begin. By operating the controls and viewing scan data, the technician can see if the desired commands of the controls, actually are transfering into motion at these motors. Here is a picture of the area that everything is located at. It is in the right rear.
I typed that and sent it before your update
So to confirm, when you have the system on SYNC, you do not have control on the rear air flow. Everything does appear to function when you take it off of SYNC and control it straight from the back. Is that accurate
That's ok, no need to apologize
Your update is very helpful
everything except for actual heat
if I'm using the front dial to control the rear, no matter what position it's on, top both or floor it all comes out that right side vent near the door.
Ok, then I'm going back to my original direction. You have 2 heatercores, one for the front and one for the back. The physical heater cores are. The actual control of the mode blend door motor, controls the air direction. The temperature blend door motor controls the warm or cool of that air. Both are located at that right rear. The problem is most likely the actual movement of those motors. Once the interior panel is removed, the movement of those motors can be verified. It is possible a motor failed or the connection between the motor and the actual doors that guide the air have disconnected or broke.
That is where the troubleshooting has to begin. As the different modes are commanded, activity should occur at those blend doors. If it does not, it then gets decided as to whether the computer is sending the command to those motors or not
If the computer is sending the command and the doors are not moving, the motor or linkage is the issue.
If the command is reaching the motors and no movement is occurring, then the computer output is the focus and why becomes the main goal
ok, so it's also possible that the heater core for the rear is bad?
Only if the air flow is normal, just with the absence of heat itself. There would be no difference in the positioning of the air flow, only the temperature of it.
OK, I will try to do what I can where you suggested. I also noticed that my SRS light is on & staying light. I guess that is related to the air bag system.
Correct. It can be due to an air bag, which your van has many, or a crash sensor, or even a seat belt component. You also have a clockspring which allows power to be fed to the air bag as the steering wheel is turned. Once the technician checks the codes that are stored in the SRS system, a code will rise above indicating which component is affected.
Is it possible that an air bag might not work in a crash if the SRS light is on?
That is completely correct as well. When the light is on, the system is deactivated.
Wow, I guess I will have to bring it to the dealer. OK Ivan thank you very much for your help today.
You are very welcome. I'm happy to assist you further if you need me. Just give me yell.
how do I do that?
Just reply to the same link that has come to your email from this question. You can simply send a reply to it, and it will bring you back to me.
OK great. well have a Merry Christmas
You too, thank you!