Hello hope everyone is doing well

I have started having problemproblems with the heating on my 2004 4.2
First of all this is what has been replaced
new radiator and coolant
New coolant hoses including the one under intake manifold
new heater control valve ome not a ebay one
Heater control panel had this rebuilt
air conditioning de gassed new o rings installed re gassed

If I clear codes the come back all the time

The fault codes

B1262 defrost servo motor circuit failure

B2426 passengers solar radiation sensor circuit open

B2537 auxiliary heater no start

B2796 driver solar radiation sensor circuit open

Symptoms
Only windshield vents working
If I press the mode button I can not get heat from center vents
Rear passenger vents only have hot

am i better to replace the whole heating unit
if so are all s types the same

Any help would be greatly appreciated
As we are coming into winter in New Zealand

Thanking you

 

I’m a little confused understanding your situation.

No heat?

Full heat at all times?

Heating seems to work normally but you’re getting some fault codes?

What of all this recent work? When did the current symptoms begin? Were parts changed trying to fix a problem? Or did the problem begin after work done for other reasons?

Please elaborate so we can help. The only thing you’ve specifically mentioned are some fault codes, which may not mean much.

 

Hi I have heat but only out front windshield vents
and only on when I push the defrost button
if I push the mode button to change settings nothing happens get no heat from center vents
Rear passengers only get full hot
knew the heater control panel was stuffed as the circuit board had burn marks


Heater control valve
Air conditioning gas was done
When I had to rebuild engine

Hope this helps

 

Okay, I'm starting to understand the scenario. As I understand it, all cabin air passes through the evaporator and then the heater core. From there, it enters a common plenum with exit ducts for three places. Electrically operated doors control which exit duct(s) are open, closed, or somewhere in between. The actuators send position feedback to the controller.

The three possible exits:

Defrost
Dash
Floor

I believe the defrost door is designed to never fully close. Even when the actuator reports it is in the fully closed position, the door is still slightly open.

The feedback gizmos are contained within the actuators. If the external linkage (to move the door) broke or became disconnected, the actuator would inaccurately report the door had moved.

That's about the extent of my knowledge on these doors and actuators. I purposely omitted much detail from the troubleshooting guide, as they are generally quite reliable and I also didn't want people getting sidetracked.

With that said, try playing around with the door controls. Try it first with the fan turned way down low. Radio off, seatbelt fastened so you don't get the chime. You want the cabin as quiet as possible. Listen for two distinct sounds:

First you should hear the whirring sound of the actuator. Next you should hear a clunk or whap as the door reaches the end of travel, along with the whir stopping. The sounds in order tell you the actuator is being commanded to run, the door responded, the actuator sent feedback, and was commanded to stop.

Next, try playing with the door controls with the fan manually set to max speed. Air will be entering the plenum. Feel around to find where it is exiting. IIRC, airflow into the footwells is somewhat diffused. It may feel weak compared to the concentrated airflow from the defrost ducts. When a warm temperature is selected, I think airflow through the dash vents is fairly weak. The bulk of warm airflow is sent to the footwells. When a cool temperature is selected, airflow through the dash vents is stronger and reduced to the footwells.

Hopefully these little details will help determine what is happening.

Also, how much have you driven the car after the engine rebuild? It can take quite a few drive cycles to purge all air from the cooling system. Until then, heating performance may suffer.

 

Blend door replacement
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