Heat Blowing Cold Air With Actuator Code B0409

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dsmith62 D I have been struggling with this car over the last six months or so with all kinds of issues. First of all it was overheating in the warmer spring/summer weather. I had previously added some head gasket sealant to the coolant a little over a year prior to this. I did this because of the notorious head gasket issue on the Northstar Engine. It performed well for quite a while. Then It started overheating and eventually the radiator blew. After I replace it My misfire was back P0301. I figured since I had such good luck with the blue devil head gasket sealant that I would add it again after flushing out the system first. It stopped the misfire immediately just like before, but I was overheating still. That part was pretty serious as I needed to travel 300 miles to my fathers funeral. I had to stop nearly every 10 mins to cool the engine. Then I got a really weird change oil message. So I stopped and changed the oil in the parking lot at Walmart along the way. The coolant reservoir was empty so I filled it and let it equalize before continuing. I pulled out of Walmart and was hitting the road and pulled out into traffic and got hit by a semi, which totally messed up the right front corner of the front end. My son took the car and made it whole again and we even had to put in another radiator. The started misfiring again with P0301 code. Added more Blue Devil. It solved the misfire once again. But now it does misfire a little on cold (very cold days here) when first started. If i keep the rpms up while the SAI is running I can avoid the misfire. Now I still have no heat coming out and a blend door error. I didnt notice it before because i was using a cheap obdII scanner which doesn't include any of the B codes. In the cooler weather the car is not overheating. It starts to get into the over the half mark when stuck in slow traffic. So I have also replaced the thermostat, the water pump and radiator since we recovered the car from the wreck. I am sure this engine is going to need head gasket replacement but its not something I can do financially and dont have any outside resources for that, thus the blue devil additive comes in. I'm sure its part of the heat not working.. Probably clogged the heater core although both exterior hoses heat up when the engine is at full temp. So, my question for now is does anyone know which blend door actuator is malfunctioning For code B0409? I have seen two descriptions but I dont know which one it is. HELP! If it's the temperature control that would total sense, but I also found a site that said it was an air flow actuator to to control upper and lower air flow. I have been driving the car after resetting the ses light which stays off as long as I dont let it misfire on cold morning starts. But I have so warm heat coming out. The AC still blows great cold air. Any suggestions? We put a lot into restoring the body after the collision and a new radiator at that time. The car after warm up runs like it always did with smooth idles like a new car. If you have had any such problems i welcome your input. I have been searching the forums, but this car seems to be past tense here now. I love driving it. It has a severe oil leak but only out on the open road at 70mph. I dont know about that part. I thought it to be the rear main seal but my son thinks it might be a pan gasket. In the city it does ok. It doesnt burn oil even at 185,000 miles. So thats a lot to take in right? If any of you people like Ranger or any of the old timers here can help. I would love it. Thank you. Dave. Car is 2002 Cadillac Deville DTS #1 · Nov 17, 2021 I have been struggling with this car over the last six months or so with all kinds of issues. First of all it was overheating in the warmer spring/summer weather. I had previously added some head gasket sealant to the coolant a little over a year prior to this. I did this because of the notorious head gasket issue on the Northstar Engine. It performed well for quite a while. Then It started overheating and eventually the radiator blew. After I replace it My misfire was back P0301. I figured since I had such good luck with the blue devil head gasket sealant that I would add it again after flushing out the system first. It stopped the misfire immediately just like before, but I was overheating still. That part was pretty serious as I needed to travel 300 miles to my fathers funeral. I had to stop nearly every 10 mins to cool the engine. Then I got a really weird change oil message. So I stopped and changed the oil in the parking lot at Walmart along the way. The coolant reservoir was empty so I filled it and let it equalize before continuing. I pulled out of Walmart and was hitting the road and pulled out into traffic and got hit by a semi, which totally messed up the right front corner of the front end. My son took the car and made it whole again and we even had to put in another radiator. The started misfiring again with P0301 code. Added more Blue Devil. It solved the misfire once again. But now it does misfire a little on cold (very cold days here) when first started. If i keep the rpms up while the SAI is running I can avoid the misfire. Now I still have no heat coming out and a blend door error. I didnt notice it before because i was using a cheap obdII scanner which doesn't include any of the B codes. In the cooler weather the car is not overheating. It starts to get into the over the half mark when stuck in slow traffic. So I have also replaced the thermostat, the water pump and radiator since we recovered the car from the wreck. I am sure this engine is going to need head gasket replacement but its not something I can do financially and dont have any outside resources for that, thus the blue devil additive comes in. I'm sure its part of the heat not working.. Probably clogged the heater core although both exterior hoses heat up when the engine is at full temp. So, my question for now is does anyone know which blend door actuator is malfunctioning For code B0409? I have seen two descriptions but I dont know which one it is. HELP! If it's the temperature control that would total sense, but I also found a site that said it was an air flow actuator to to control upper and lower air flow. I have been driving the car after resetting the ses light which stays off as long as I dont let it misfire on cold morning starts. But I have so warm heat coming out. The AC still blows great cold air. Any suggestions? We put a lot into restoring the body after the collision and a new radiator at that time. The car after warm up runs like it always did with smooth idles like a new car. If you have had any such problems i welcome your input. I have been searching the forums, but this car seems to be past tense here now. I love driving it. It has a severe oil leak but only out on the open road at 70mph. I dont know about that part. I thought it to be the rear main seal but my son thinks it might be a pan gasket. In the city it does ok. It doesnt burn oil even at 185,000 miles. So thats a lot to take in right? If any of you people like Ranger or any of the old timers here can help. I would love it. Thank you. Dave. Car is 2002 Cadillac Deville DTS See less See more Sort by Oldest first Oldest first Newest first Most reactions #2 · Nov 17, 2021

dsmith62 said: I have been struggling with this car over the last six months or so with all kinds of issues. First of all it was overheating in the warmer spring/summer weather. I had previously added some head gasket sealant to the coolant a little over a year prior to this. I did this because of the notorious head gasket issue on the Northstar Engine. It performed well for quite a while. Then It started overheating and eventually the radiator blew. After I replace it My misfire was back P0301. I figured since I had such good luck with the blue devil head gasket sealant that I would add it again after flushing out the system first. It stopped the misfire immediately just like before, but I was overheating still. That part was pretty serious as I needed to travel 300 miles to my fathers funeral. I had to stop nearly every 10 mins to cool the engine. Then I got a really weird change oil message. So I stopped and changed the oil in the parking lot at Walmart along the way. The coolant reservoir was empty so I filled it and let it equalize before continuing. I pulled out of Walmart and was hitting the road and pulled out into traffic and got hit by a semi, which totally messed up the right front corner of the front end. My son took the car and made it whole again and we even had to put in another radiator. The started misfiring again with P0301 code. Added more Blue Devil. It solved the misfire once again. But now it does misfire a little on cold (very cold days here) when first started. If i keep the rpms up while the SAI is running I can avoid the misfire. Now I still have no heat coming out and a blend door error. I didnt notice it before because i was using a cheap obdII scanner which doesn't include any of the B codes. In the cooler weather the car is not overheating. It starts to get into the over the half mark when stuck in slow traffic. So I have also replaced the thermostat, the water pump and radiator since we recovered the car from the wreck. I am sure this engine is going to need head gasket replacement but its not something I can do financially and dont have any outside resources for that, thus the blue devil additive comes in. I'm not sure which part of the heat is not working.. Probably clogged the heater core although both exterior hoses heat up when the engine is at full temp. So, my question for now is does anyone know which blend door actuator is malfunctioning For code B0409? I have seen two descriptions but I dont know which one it is. HELP! If it's the temperature control that would total sense, but I also found a site that said it was an air flow actuator to to control upper and lower air flow. I have been driving the car after resetting the ses light which stays off as long as I dont let it misfire on cold morning starts. But I have no warm heat coming out. The AC still blows great cold air. Any suggestions? We put a lot into restoring the body after the collision and a new radiator at that time. The car after warm up runs like it always did with smooth idles like a new car. If you have had any such problems i welcome your input. I have been searching the forums, but this car seems to be past tense here now. I love driving it. It has a severe oil leak but only out on the open road at 70mph. I dont know about that part. I thought it to be the rear main seal but my son thinks it might be a pan gasket. In the city it does ok. It doesnt burn oil even at 185,000 miles. So thats a lot to take in right? If any of you people like Ranger or any of the old timers here can help. I would love it. p.s I really dont know which blend door activator does what Thank you. Dave. Car is 2002 Cadillac Deville DTS Click to expand...

#3 · Nov 17, 2021 (Edited) that's quite the novel you have written - the condensed version is always preferred - when referring to DTC's we ALWAYS ask that you include the DEFINITIONS from THIS site - CTS-CTS-V FAQ: Cadillac On-Board Diagnostic Trouble Codes (OBD-II) with that said - B0409 - Air Mix Door #1 Range Error - MIX door #1 is the DRIVER side mix door - #2 is the PASSENGER side and #3 is the back seat - if BOTH heater hoses are EQUALLY HOT coolant is flowing through the heater core so - addressing the actuator issue should resolve the heat issue - TRY "exercising" the actuator - set the MODE to the dash vents so you can easily feel the air temp - adjust the cabin temp from 60 to 90 - let it sit for 2 to 3 minutes - NOTE the temp change - set the cabin temp from 90 to 60 - let it sit for 2 or 3 minutes - NOTE the temp change - do this several more times - did this procedure improve the heat? if NO - replace the actuator - the part you need is ACDELCO 15-72974 - $57 - with free shipping -

Amazon.com: ACDelco GM Original Equipment 15-72974 Air Conditioning Vacuum Actuator : Automotive

Buy ACDelco GM Original Equipment 15-72974 Air Conditioning Vacuum Actuator: Balance Shaft Parts - Amazon.com ✓ FREE DELIVERY possible on eligible purchases www.amazon.com it CAN be replaced from up/under the dash - ========================= regarding the engine - after dumping in 3 DOSES of the blue devil CRAP - I wouldn't do anything but REPLACE it - Insert Quotes Post Reply

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