Why do you need to get at it? What is your symptom?

 

with the heat cranked i have warm air on the drivers side and roasting hot on the passengers side. no codes, just had my rad flushed a couple weeks backs, and both the in line and out line to the heater core are hot.
i want to take it out and manually flip the vent to see if i can get hot air, if i do i'll see if i can get it working or replace.

 

How old is the t-stat? it sounds like the passenger side is getting hot but just wondering if the t-stat may be stuck open. Does your temp guage go to the middle between hot and cold? I suppose you'd get a CIL if the t-stat malfunctioned. Another thing is listen when you turn on the heat to see if you can hear those doors open and close.

 

i figure if it was the t-stat i would only get warm heat on both sides, the passenger side is so hot the plastic on the vent is almost too hot to touch. i actually have a new t-stat in the box, was going to replace it, got the below operating temperature code like 2 yrs ago, meaning the t-stat was stuck open, only got the code a few times so i ignored it, and it never came back. i'm wating for the summer, i'll change it then, going to do some maintanence then, so i'll do it all in one shot.
i cant' hear the vent opening or closing, but i can get cooler on that side, and the passenger side is fine. the only other thing i could think would be the heater core, but i figure i would get poor heat to both sides.
so by deduction i came to the conclusion it's the blend vent motor, i want to get at it without ripping my whole dash out.

 

Sounds the you did your homework and the door is the next step. Maybe send a msg to ewill to see if he has ever done this.

 

ya, i'm going to crawl under the dash today hangover permitting, if i can't find it i may have to shoot him a message. i have the service manual repair proceedure, it shows a pic of it, but doesn't really show where it's at. all's i know is that they are on each side of the heater core. i really don't want to take out my dash to get at it, so i'm hoping removing the kick plate is enough.

 

well found the blend vent motor, and it appears to be working fine. i turned the heat up and down and could watch the mottor move the vent arm. i'm not sure i could get it out anyway, without ripping apart the dash. but now i'm stumped, next step is back flushing the heater core, maybe when i got my rad flush it dislodged some crud, i'm hoping when they flushed the rad they did the heat loop too. i placed some cardboard in front of the rad to make sure my engine temp is getting up there, still same thing. i ran the car with the rad cap off to let any trapped air out, and did see some bubbles for a while, i even squuezed the rad hoses to help if there was an air lock.
unless the blend vent door has something physically wrong with it, i'm going to assume now its the heater core. strange that both lines comming from it are hot, the exit line maybe slightly cooler, i figure that would be normal. weird i would get perfectly good heat on one side, but i guess if the air takes a longer route to get to the drivers side it could explain why it's cooler.
if it wasn't -10 here i would back flush the core myself, but i guess i'm off to get it done today.

 

What temperature are you getting on the passenger side vs the drivers side? If you want, I could measre mine and compare. tell me what the heat setting is and where exactly are you measuring. I have and indusrtial HVAC thermometer and I can record both sides.

 

thanks for your help. i don't have access to a hvac thermometer, so that might not help me out, i went to go get my heater core back flushed and they are convinced it wouldn't help, i wouldn't get heat on both sides, so they say. so i guess instead of wasting money on a flush i'll ride it out untill it's warmer here, then flush it myself. if that doesn't help then i'll take apart my dash and see what i can see.

 

If you have a meat thermometer, use that. Turn the heat up as high as it will go and read the temp in the four upper vents. I'll do the same and give you my readings tomorrow.

 

thanks again for being willing to go through all that exrta hassle. i don't have any thermometer of any type, but i'm sure i can grab one at the dollar store. not sure what that will tell me about the cool side, but may tell me if my hot side is atleast the right temp.

 

your problem is the vent door inside the dash i had the dealer look at mines and i was told by the dealer that they would have to remove the dash to fix for 345.00

 

where did you look to see the vents opening and closing what did you take apart to see that

 

i took out the kick plate under the drivers side dash. look above the gas pedal, while looking up it's on the left aginst the heating/cooling unit, you'll see a black box with a white plastic arm, the box is the bled vent motor and the arm it moves controls the vent, there is another box above it and slightly behind it that looks the same, that one is the air mode selector, which controls recirculaing air or fresh air. if you adjust the temp setting on the drivers side you should see the arm move, if not the motor is faulty. if you press the recirculator button, you should see the arm move on the other box. there will also be one on the passanger side that controls that sides blend vent.

 

i have heat on the passenger side all the time so i'm trying to fix this problem without going to the dealer hopefully i can get to the motor will see thanks

 

you may have to take out the center console to removel the motor, seems like a tight fit to me from under the dash. there are bolts behind the ashtray, center vents and head unit, so all of those will have to be removed, then there are two behind the lower dash under the steering wheel so, that piece will have to be removed, and the plate inside the glove box to get the other two on that side. let me know what you find.
the motors themselves are only like 40.00 bucks online.
mine doesn't seem to be motor related as i once thought, if anything there is a problem with the vent door itself on mine.

 

I turned my heat up to 90 degrees (manual) and hit the A/C off button. The three upper vents in the center of the dash read 140 degrees, the two upper side vents, left and right, read 130 degree. There doesn't seem to be much difference between the drivers side and the passenger side.

Note: I replaced my T-stat last Nov. My suggestion would be to try to find out if there are two different hoses feeding the heater core.

 

my top center vents read 123.3 degrees, passenger side 2 vents read 147.4 degrees and far drivers side vent 106.5 degrees and an ambient out side telp of 37 degrees.

 

It may be a clogged core, I searched and found this from ewill3rd:

http://www.cadillacforums.com/forums/cadillac-cts-forum-2003-through-2007/132672-cts-heat-blink.html

 

I had a base CTS that lost heat and I tried everything to clear the heater core.
I did have to replace it, and when I cut it open there was corroded debris in there that was just in there, no way to get it out.
How does the coolant look?
If it's nasty you might be in for a big expense.
This was not an easy job on CTS.

 

coolant looks good , just had it flushed a couple weeks ago,(seems my heat died shortly after) the old coolant looked normal too. was talking to a mechanic friend of mine and he says if its not the blend vent flap then they could have air locked the heater core. maybe there is air bleed screws in other places? he says it could be tough to remove the lock with out bleeding it properly and removing the rad cap may not do it.
he also said that maybe the way the vent ducts travel it may be why my heat seems one sided.

 

These dual zone things are tricky. The car in that other post came in with heat on one side but not very good. The more I tried to flush it the worse it got.
I'm not saying go right for the heater core, but don't rule it out.
Be sure to eliminate every other cause first.

Air locking should be a temporary issue, usually once you drive them on the highway for a while it will push any air out of the core.
The CTS doesn't give you anywhere to bleed air out.
I acutally use a tool called a Vacu-fill that works really good at filling systems without leaving air pockets.
I always use it as some of these cars like to harbor air. The worst I have seen yet is XLR for that.

That one I wrote about before, I flushed it, backflushed it, and flushed it sideways for like over 2 hours, but the debris was just trapped in the bottom tank, no way out.
I hope that isn't it, but....

Good luck either way.

 

yes thank you, i'll try back flushing first, seems an easier first step than taking my dash apart for a faulty vent door. even if i do that and it checks out ok atleast i know its clean.

 

just got back from a heatercore flush, everything checked out ok, no clogging at all. back to the vent door, mechanic said it might not be closing the whole way. funny the motor works and i can feel it changing the temp as i go up or down, just on full it doesn't get as hot on the drivers side. what a pain, but i'm glad the core checked out.

 

i hope you get this figure out its about to be summer time and i have all hot air on the drivers side i am getting a code P0409 so i hope i don't have to pay that 345.00 at the dealer going to play with it tomorrow going to see if i can get the vent doot too close the dealer told me a while back this is a common problem