Chrysler 300M Enthusiasts Club
  • Heater Blend Door Actuator? Advice

  • General Discussions about the 300M and other LHs
2022 Calendar Banner

Membership Banner

General Discussions about the 300M and other LHs

Moderator: Moderators

User avatar
 #389678  by Stevelaz
 
Hello Everyone, The other day i got in my 2004 300m and i was getting no heat at all, just cold air. The temperature was going up normally and there was plenty of antifreeze and it was not overheating. It was like that for a few days. Well the other day when i was in it I messed with the climate control and put the temp all the was down to low and then back up to high. Low and behold the heat started blasting HOT and has working ever since. Is this something i should be concerned about? Would this be the actuator starting to go bad? Should I just let it go and see what happens? Is there any knowledge base on procedures to replace? Thanks!
User avatar
 #389679  by FIREM
 
Somewhat common and annoying for the blend door actuator to hang up. All summer in A/C mode now asked to provide heat.
There is a reset procedure in the KB that may work.
Last 2 years of my Pro-Am’s life even the family knew the reset procedure. I was just to cheep and lazy to change the Blend Door Actuator
TrepKing95 liked this
 #389687  by RobNJ
 
Do the resync procedure and see if the DTC comes up at the end. My guess is it will and the actuator is failing. Not too bad of job, but you need to be prepared for some tight working spaces and unnatural bending of your body. It is located in a terrible spot and screws are not easyto get to. Small tools are a must.
I used to resync mine once in the summer and once in the winter to get the system in the right temp zone for the season. Got to the point where that no longer worked and i had to change it out.
User avatar
 #389690  by Stevelaz
 
Ok, Thanks! I did look at the replacing procedure and it looks like a pita. I will let it go for now and see what happens. Also i will look for the resyncing procedure and give that a try...
User avatar
 #389691  by Stevelaz
 
Ok, I just did the resync procedure. I did hear the door moving around Darn, code 23 "Blend door actuator feedback failure" came up at the end. it is working fine now so i will probably leave it for now...
User avatar
 #389695  by First Lady
 
I second that body contorting required to replace! Relatively easy overall but stretch before!
User avatar
 #389704  by FIREM
 
Much easier to just push a few buttons now and then for heat. Saves a trip to the chiropractor.
User avatar
 #389712  by LUNAT1C
 
Agreed, I would let it go and rely on the occasional ATC recalibration to band-aid it until it becomes a multiple-times-a-week nuisance.

I've been lucky so far in that my only HVAC actuator problem was my mode door actuator, and that was self-induced and much easier to get to and correct. Counted my chickens two weeks ago going to Myrtle Beach and the car was more than happy to supply heat, followed by equal happiness to supply A/C when heading further south to Charleston (in spite of a small condenser leak that is waiting until next Spring for replacement).
User avatar
 #389715  by Stevelaz
 
Well it seems to be working great since resync, seems even better. I used the car yesterday to run some errands and the heat blasting on high at 90 degrees was coming out of the vent so hot I couldn’t keep my hand there. Lol. Hopefully it last a while!

Oh, and I put a thermometer in a dash vent and the temperature was about 150-155 on highest setting! Is that what it should be? Seems rather hot to me.
User avatar
 #389717  by LUNAT1C
 
Someone more knowledgeable can correct me, but as I recall the engine coolant gets up to about 210F. Considering heat loss in the heater lines and in the heat exchanger in the HVAC box, 150F doesn't seem unheardof at full Hades. It will quickly cool as the air heated by the heat exchanger passes through the vents into the much cooler cabin. That heat energy will continue to disperse in the cabin, and I'm sure eventually the ATC will detect some upper threshold even when it says "Hi", or otherwise pull back the reins if set to a specific high value.
User avatar
 #389721  by FIREM
 
150 not unusually hot for outlet temp. There may even be temps listed in the FSM that high if I recall.
 #389722  by TrepKing95
 
LUNAT1C wrote: November 23rd, 2021, 1:58 pm Someone more knowledgeable can correct me, but as I recall the engine coolant gets up to about 210F. Considering heat loss in the heater lines and in the heat exchanger in the HVAC box, 150F doesn't seem unheardof at full Hades. It will quickly cool as the air heated by the heat exchanger passes through the vents into the much cooler cabin. That heat energy will continue to disperse in the cabin, and I'm sure eventually the ATC will detect some upper threshold even when it says "Hi", or otherwise pull back the reins if set to a specific high value.
If you set the ATC to Hi or Lo it will "lock" the blend door in its hottest or coldest setting, ignoring other inputs. I just checked the FSM specs, and at an ambient temperature of 60°F, the minimum temperature from the floor vents with full heat, full fan settings on a fully warm engine is 144°F. The highest the chart shows is 153°F is minimum at 90°F Ambient. Pretty sure if you're getting 155°F air at anything less than 90°F, your system is functioning properly.

I have always found the ATC in the 300M to work best when set to 72°F Auto under 90% of the conditions I drive, with the exceptions of ice in the winter requiring full defrost, or when I've been doing activities outside on a hot summer day and want the arctic blast to continue for longer than required on Auto. I will occasionally set it to 75°F Auto when I want a cozier feel in the cabin.
User avatar
 #389746  by hrmwrm
 
after a certain coldness, i just set it on high and modulate it with fan speed.
most of my miles are highway where losses to speed are higher too.
imagine that would be too hot in traffic driving.
works for me and stops my blend door from being overused.
and summer is coldest setting, using a/c when needed.
disconnect the a/c compressor every winter too.
stop it from running with defrost in the winter.
22 years old, still original a/c.
doesn't get used alot in my climate.
User avatar
 #389773  by Stevelaz
 
hrmwrm wrote: November 25th, 2021, 10:34 pm after a certain coldness, i just set it on high and modulate it with fan speed.
most of my miles are highway where losses to speed are higher too.
imagine that would be too hot in traffic driving.
works for me and stops my blend door from being overused.
and summer is coldest setting, using a/c when needed.
disconnect the a/c compressor every winter too.
stop it from running with defrost in the winter.
22 years old, still original a/c.
doesn't get used alot in my climate.
That's interesting, Is it ok to disconnect the A/c compressor? What/where do you actually disconnect?
User avatar
 #389774  by LUNAT1C
 
I'm assuming he is referring to the electrical connector on the compressor. I have never heard of anyone doing that during winter, and personally wouldn't since the defrost uses the compressor to function.
Stevelaz liked this