RHYS

So I have heat and ac going through rear vents, but only cold air coming out of the front. ( I am aware that there are two separate climate controls for rear and front.) I filled coolant, bleed lines etc, but if I am getting hot air in rear there should not b a need for this correct.

I guess I am just confused as to why the rear gets heat but not front...why would this happen when the hot/cold **** controls both front and rear climate?

Thanks

Uplander 2006 3.9L

RHYS

Hey guys, I am really looking for some advice on this and any help would be appreciated. So today I took out the front dash of the car and checked all three blend doors which are under the driver sides and all are working as they should and turning. I also took out the two air filters which are behind the glove box and they were pretty bad. I was hoping this was the problem. I cleaned them out and put everything back together. Still I have heat going to the rear of the van but not the front. I have checked all the fuses and after checking the blend doors I am at a total loss..Any thing I am missing? Are there two heater cores for the van for both front and back and it is possible the front has gone? Thanks

tech2

think there are 2 heater cores front and rear. can you feel the front heater core inlet and oulet hoses at the firewall in the engine compartment. One should be hot and the other slightly cooler.

does the system produce heat from the front when the engine is rev'ed and held at 2000rpm?

RHYS

thanks Tech2. From what I was able to find out today the van does have two heater cores. One is located in the back on the driver sides in the trunk area. The other is in the front. When I get home tonight I am going to check and see if I can see the front core inlet and see if I can flush the system. REALLY dont want to have to change the front one if it is broken. When the car is rev'ed still no heat. Heat to the back is perfect though.
does anyone have a photo/diagram of where the front heater core is located? thanks

RHYS

So been looking at different things for week. Here is where I am. Still no front heat. Blowers are working between speeds 1-5 and I have cleaned out all the filters and although dirty still no heat. Blower is working strong and all front zones are working. Thermostat looks good and coolant level is good. No need to top it off. If the front heater core was bad would I not be leaking fluid and need to top of regularly?

I checked the two hoses going into the heather core by the firewall and top is warm and bottom cooler…I flushed this out too.

Checked all front blend doors and they are also working correctly….so I am at a complete loss of what else it could be and it looks like I will have to take it to the dealership..which I do not want to do, but I need front heat in the car. Thanks---I may just take the whole front dash off just so I can see the heater core!!


Rear of the van is working fine both hot and cold. I know it has separate a heater core and it works perfectly.

Papa Bear

How did you check the blend door(s) ?? .....

If the blower is moving air out of the vents and there is hot water through the heater core then that just leaves blend door(s) problems. IMHO

RHYS

I actually took each one out and tested that they were moving correctly..maybe I am getting confused with the name..'actuator' perhaps. I had trouble in the past with a Ford and when I replaced the blend door/actuator thingy it worked.

yeah I agree we have hot water going to heater Core and blower blowing but no heat through any of the front vents. I though it was the blend door, but they are all turning clockwise and anti clockwise when the climate control **** is turned.

RHYS

I am going to solve this problem with the van...even if it kills me. Still no heat in the van and I have been busy for the past month and spent last week putting new tire rods on the van.

I am looking for some advice. I went to autozone yesterday as it just opened in the area and the explained to the guy working what was wrong with the van Rear Heat yes - Front Heat no and straight away he said it must be my blower resister (Front)...I said that all my dials were working 1,2,3,4 and 5 and he said typically that is what the resister controls, but lately he has heard of people having the same problem with no heat and it has been the blower resister...thoughts? Does the resister have anything to do with not getting heat in the front?
Thanks

tech2

the blower resistor is used to control the blower motor fan speed. So if your getting different fan speeds the blower is working. It has nothing to do with the temperature of the air.

stpiean

hi
I have a 2009 Uplander and have had no heat on idle since it was a year old. this is a GM design flaw. GM Rep told my dealer they had placed the front core to high within its molding in the firewall, so continuous air locking.

I am fighting with GM, as this is a factory default and a lemon. any others out there with same issue