Cadillac Owners Forum banner

1 - 19 of 19 Posts

·
Registered
2005 Stealth Grey CTS-V
Joined
·
126 Posts
Discussion Starter #1
Hi All,

Wondering if anyone else has had this problem and what the fix for it was.

My car blows cold air out the driver side, I can't get heat out of it no matter what I do. The passenger side works fine though.

So, my first thought is that it's the motor (actuator) that opens and closes the flap for the heat.

But, when I start the car in the morning it's cold obviously. Usually the hvac fan will stay off until the car warms up enough and then it will start blowing heat. What's happening now though is that the car starts blowing as soon as I start the car.

I can't quite figure out why this would be happening. If I jack the temp on the driver side way up or way down it starts blowing like crazy so it seems the HVAC computer itself is ok.

I'm thinking maybe it's the thermometer? If the termometer stopped working would it default to some base temperature? The outside temp these days is around 50, I have my hvac set to around 75 degrees. That would mean that the default would have to be below 50 for it to think that the car is too warm and it needs to fire up the fan right away then no?

What I've had to do is leave it on vents only, close the driver side vents, and point the passenger side vents towards me.

Thanks to anyone for help,
Robin.
 

·
Registered
06 CTS-V
Joined
·
2,497 Posts
Had the exact same thing happen in my CTS before, same set up in the V. Most people would point to the blend vent actuator motors, some times they do die. If they get stuck in an open position allowing outside air in it will cause low temperature on one side. If you take out the kick plate under the dash you can see the motors and the arm they move, you have to get your head right under the dash to see them, there are 2 on each side. While your head is under there get someone to push the heat on that side all the way hot and all the way cold, if the arm moves on one of the motors it is fine, the other actuator is controlled by the recirculator button. I can't remember which motor is which( top or bottom) one motor is right above the other.
When I had my problem I couldn't find any problem with the actuators, everybody I talked to said it wouldn't be a plugged heater core(except ewillard from Lindsay) I even payed to have my heater core back flushed, even though they insisted it wouldn't be any use. I think they just took my money, because it didn't help. Just prior to having my heat problem I did have my cooling system flushed, so all points led me back to the heater core.
Both my heater core in and out line were hot, so that had me puzzled. Apparently after talking to Ewillard the heater core in the CTS if it gets clogged it can cause poor heat on oneside, contrary to everyone others beliefs.
I decided to back flush the heater core myself. There are two lines going into the top of the firewall in the engine bay on the passengers side.
I pulled those, and hooked up several feet of some clear tubing I picked up from the hardware on each of the lines. then blasted it with a garden hose. I immidiately saw debry come out. Then I blew the core dry with my mouth and poured in rad flush chemical, pushing it in by mouth until it surfaced in the other line. I let the flush sit for abou 1/2 an hour, then flushed it out with a garden hose agian. With the garden hose on i would plug the other line with my thumb and release, several times, untill no debry came out. Then I would flush it the opposite way.
While there was some debry from flushing, I was surprised how little the was. When I was done I refilled the rad, started the car and BAM I had perfect heat.
I would try to backflush before deciding on a new heater core, because you pretty much have to take out your whole dash to replace it.
Also becarefull how much water pressure you use to backflush because you don't want your heatercore to spring a leak.
 

·
Registered
2005 Stealth Grey CTS-V
Joined
·
126 Posts
Discussion Starter #3
Thanks Tommy. I had searched and saw your post before with all the troubles you went through. I'm thinking my situation was a bit different though because I get no heat at all. I appreciate your feedback, I may try to flush it this weekend anyway, it could probably use it.

I'm going to pull the kick panel out this weekend as well and check it out.

Thanks,
Robin.
 

·
Registered
06 CTS-V
Joined
·
2,497 Posts
I guess the more it's clogged the less heat you would get, maybe to the point of getting no heat. The way it's designed, if there is sediment in the bottom of the heater core plugging the fins the you won't get heat/or poor heat to the drivers side. The blend vent actuator are easy to see and cheap to buy, but are a pain to remove. Luckily the one that is probably causing the problem to the drivers side (if that is the case) is the easiest to remove out of all the motors.
With those possibilities eliminated, the next cheapest route would be the cabin temp sensor, I believe the drivers side is the one to the right of the steering wheel on the dash board, behind the plastic grate. I have no Idea if or where the passengers side one is. I priced out the sensor before when I was troubleshooting and it was around 20.00 or so.
I'll still place my money on the heatercore. If you've ever had your rad fluid topped up at a quick lube or garage and they didn't use dex-cool, I would consider it suspect.
 

·
Registered
2005 Stealth Grey CTS-V
Joined
·
126 Posts
Discussion Starter #6
Well, I verified that the motor for the temp control is still working. I took off the kick panels and crawled underneath. I could see that the motor was opening/closing when I adjusted the temperature.

I'm thinking that you're right about the heater core now. It must have two sections or something? That would be the only way to explain why the heat is fine on the passenger side and cold on the driver side. I'm going to try to flush it sometime this week or maybe this coming weekend.

I'm also thinking that maybe the temp gauge isn't working as well. I just can't figure out why the car would start blowing air immediately after I start it. It shouldn't start blowing until the engine temp reaches the proper temperature.

R.
 

·
Registered
2005 Stealth Grey CTS-V
Joined
·
126 Posts
Discussion Starter #7
Hey Tommy,

Looks like you were right! I had a hard time believing that it would be the heater core but I did as you said and flushed it yesterday. I actually flushed the whole system as well as flushed the heater core separately. This morning I had hot air coming out of the driver side so it seems fixed.

There didn't seem to be anything strange flushed out, the antifreeze looked fine but who knows.

I think the initial problem could be because I used regular antifreeze to top it off before instead of dexcool. It wasn't much, maybe 1/12 of a jug but maybe that could have been it.

Thanks for your input, it's very much appreciated.

Regards,
Robin
 

·
Registered
06 CTS-V
Joined
·
2,497 Posts
No prob!! glad it worked for you. I couldn't believe that it would be the heater core when I had problems either. I figure the way it's designed is it takes heat from the bottom of the core for the drivers side and the top of the core for the passengers. If the bottom gets clogged with sediment the heated water will just bypass that area and heat the top of the core. With the passangers side ducts taking heat from the top half of the core, you onlly get one side. Considering that most peolple that complain of no heat one one side it always seems to be the drivers side.
I think that dex cool mixed with other coolants can cause a sludge build up, and the heater core being so small with fine passage ways would probably be the first thing to get clogged.
With my CTS I flushed out all the dexcool and ran a regular long life coolant instead. Dex-cool i'm sure is fine, but if you mix it, it can cause real problems, there was even a class action lawsuit held against g.m. for dex-cool.
Mind you having an 05 it was probably time for a full flush anyway.
 

·
Registered
2003 CTS
Joined
·
2,339 Posts
Hi guys,
Regular CTS'er here, just wanted to chime in over here. I followed Tommy's description and it worked like a charm. I have heat on both sides again. I used Peak radiator flush and 10 feet of 3/4 O.D. x 5/8 I.D. clear vinyl tubing that I got from Home Depot. Overall took about 2 hours.
Thanks for the help Tommy!!
 

·
Registered
'06 DTS performance; CowboyCadillac='12 SVT Raptor; 2014 XTS-Vsport
Joined
·
634 Posts
Dex-Cool is an OAT (organic acid technology) anti-freeze and the 'NEW' extended life anti-freezes are hybrids (HOAT) that are compatible with both 'conventional' & Dex-Cool. But, do not mix 'conventional' with Dex-Cool. The ph & chemistry are not compatible.
And that's the way it is. :)
 

·
Registered
none
Joined
·
1 Posts
2005 cadillac cts. Heater a/c fault
can any one help
heater blend motors both inop.
No signal from controle unit
motors work ok when powered from a different circuit.
Fault codes just say heat blend motors faulty
suspect controle unit.
Is controle unit the switch pack, or is there a seperate ecu.
Has any one got a wiring diagram ?

Thanks chris
 

·
Registered
2005 Stealth Grey CTS-V
Joined
·
126 Posts
Discussion Starter #13
Def sounds like the control unit. As far as I know all the 'brains' are all contained within the actual hvac control module itself (the unit in the dash where you change temp, etc). Here are two pics that may help, sorry, no schematics.
cts blower case.gif

cts floor ducts.gif

Good luck,
R.
 

·
Registered
2011 CTS-V COUPE, 2006 DTS Perf
Joined
·
1 Posts
Well guys I just flushed out the Heater cores on my wifes 2008 CTS AWD as there was no heat on drivers side and waaalah heat again! It was a choir but she is fine.
Weird little white hair balls came out like 1/4 the size of a BB.

Thanks for the info...
 

·
Registered
2005 Stealth Grey CTS-V
Joined
·
126 Posts
Discussion Starter #16
Make sure you're using the proper Dexcool antifreeze, otherwise it could be gelling up in there.
 

·
Registered
2005 Stealth Grey CTS-V
Joined
·
126 Posts
Discussion Starter #18
Haha, yeah, well I have notifications turned on for any of my long past posts so this popped up in my email. Sadly I wrecked my V a couple of years ago and still miss it. Hoping to get an ATS-V in the next year or so or a Gen 2 CTS-V possibly. They're very difficult to find here where I am though (Vancouver, BC).

Cheers.
 

·
Registered
Joined
·
2 Posts
Yesterday I experience a long two year situation come to an end. After a thorough review of all the replies in the forum, I decided to start with Back Flushing my 2005 CTS heater core. I flushed it from the output to the input side of the HC with water with a battery power power washer because of the lower PSI. Then back it up with CLR cleaning agent from the store that I let soak inside the HC for an hour. Then as I flush that out with water first it was little fragments of stuff coming out then there was clots of white stuff and I reversed the flush from input to output and more white stuff started coming out in the clear clear 5/8th ID hoses in bigger and smaller pieces. I did this a couple more times and refilled the HC with Dexcool AF 50/50 and reconnected the hoses. Started the car let it warm up and there was a lukewarm on the drivers side that was ice cold at first. So I figure I'll do it again the next day it couldn't hurt. Fast-forward next day I started with the CLR letting it soak for an hour - more white stuff coming out and some clumps of stuff - lots of it filled the clear hoses. Stepping it up, I sprayed only ample WD-40 into the hoses and blew it through back and forth side to side a few times with my mouth and let it sit for another hour more stuff came out with a water flushing. Reconnected everything and started up car and bam! I got real heat. I will do it again today to match the heat on the passenger side. But this is the ANSWER! Hope you can use it or at least try this first all you need is clear hose, water/hose, CLR.
 
1 - 19 of 19 Posts
Top