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Repair Questions and Answers.

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 #392378  by p-ROCK
 
Little stumped on this one. I have a 99 300m with about 50,800 (true, one owner) miles on it. The mode and blend doors stopped responding and I ended up making the dorman mistake and they were swapped out. Next was the ATC module and now the BCM.

The blend and mode doors do not respond to commands, they only respond to the calibration test. It goes through the full range when you run that. Always seems to end up with 32 and 33.

Is there a ground somewhere people have had problems with somewhere on these when they’ve sat most of their lives? The doors do not seem binded, the actuators mounted or not seem to respond only when in calibration.

Sometimes I can get lucky and find a sweet spot where turning off the ATC will cause everything to go home, then it will respond for a while to commands. Sometimes though it ends up slowly adjusting to heat full blasts and cooks me to oblivion.

Really weird one, anyone run out of part tossing or have the weird one offs like me? This car will be difficult to pass with, grandpa>mom>me. I’m a jag guy myself and wrench on those, but I’ve liked this specific car ever since I was a kid, so I’m in it for the long haul. :)
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 #392380  by LUNAT1C
 
Interesting, sounds like the problem isn't always there, correct? Has any work been done on the car that was at all related to the HVAC system inside the car? Evap, heater core replacement, ATC disconnected (even for unrelated reasons), etc.?

When I had an issue with my mode door actuator, I was pulling my hair out trying to figure it out. I had soldered the contacts inside the actuator to try fixing the connection, tried a newer unit from a yard (from a 2004 car into my 02) and an older but known good unit from a member here (from a 99) and still had an issue. Turned out some knucklehead mounted it wrong after reassembly following evaporator replacement (it's me, I'm some knucklehead) and the doors were mounted in the same track on the actuator.

But it sounds like your issue wouldn't be that if you're able to "get lucky" every now and then and it operates normally. There are a couple grounds in the cabin that can be checked, they're on the tunnel, driver's side near the gas pedal and behind the carpet. If you've already replaced the actuators then you've already been near them.


You can also try soldering the connections inside the actuators. I did it myself before I realized my mistake with the doors and didn't hurt anything, I put my original 2002 actuator back in and have the 99 and 04 actuators "in stock" now.

Mode door actuator repair for code 24: viewtopic.php?p=380140&hilit=mode+door+actuator#p380140



I did a little digging because I recall someone else having a number of ATC codes come on at once and found this thread. This forum member in Scottsdale had your two stall codes as well as feedback codes for the same actuators. It seems his fix was to have the BCM worked on supposedly by Chrysler. I don't know exactly what was done other than his mechanic pulling the BCM and sending it out for repair. This was after replacing the ATC with NOS and was followed by replacing one of the actuators.

viewtopic.php?p=357452&hilit=ATC+codes#p357886
 #392386  by p-ROCK
 
LUNAT1C wrote: November 30th, 2022, 10:22 am Interesting, sounds like the problem isn't always there, correct? Has any work been done on the car that was at all related to the HVAC system inside the car? Evap, heater core replacement, ATC disconnected (even for unrelated reasons), etc.?

When I had an issue with my mode door actuator, I was pulling my hair out trying to figure it out. I had soldered the contacts inside the actuator to try fixing the connection, tried a newer unit from a yard (from a 2004 car into my 02) and an older but known good unit from a member here (from a 99) and still had an issue. Turned out some knucklehead mounted it wrong after reassembly following evaporator replacement (it's me, I'm some knucklehead) and the doors were mounted in the same track on the actuator.

But it sounds like your issue wouldn't be that if you're able to "get lucky" every now and then and it operates normally. There are a couple grounds in the cabin that can be checked, they're on the tunnel, driver's side near the gas pedal and behind the carpet. If you've already replaced the actuators then you've already been near them.


You can also try soldering the connections inside the actuators. I did it myself before I realized my mistake with the doors and didn't hurt anything, I put my original 2002 actuator back in and have the 99 and 04 actuators "in stock" now.

Mode door actuator repair for code 24: viewtopic.php?p=380140&hilit=mode+door+actuator#p380140



I did a little digging because I recall someone else having a number of ATC codes come on at once and found this thread. This forum member in Scottsdale had your two stall codes as well as feedback codes for the same actuators. It seems his fix was to have the BCM worked on supposedly by Chrysler. I don't know exactly what was done other than his mechanic pulling the BCM and sending it out for repair. This was after replacing the ATC with NOS and was followed by replacing one of the actuators.

viewtopic.php?p=357452&hilit=ATC+codes#p357886
Thanks for the response and indeed it is interesting!

No major hvac systems have been replaced other than the compressor. The car blows ice cold and really doesn't appear to be losing freon, the A/C machine I use at the shop shows any significant loss, just an oz or two off what I charged it with but I'm used to that and the scales on those goofy things.

Last year I put a dorman blend door actuator (I'm going to say the really PITA to get actuator in case I'm mixed up here) in it and it lasted. Had the mode door go out, swapped that out with a dorman. Things were great until I randomly did what I do with things and ran a calibration. All went to crap after that.

Swapped both units out with non dormans, went from the feedback (23 and 24 I think) and 32 and 33 to just 32 and 33. When I replaced the blend door with a non dorman, it was pretty wet, that was a bit sketch. Since I'm not losing freon I hope I don't have the evap pinhole leak, didn't look like coolant just rusty iron water. The old dorman definitely had some rust on the top of the motor when i took the cap off.

The ATC I got a reman'd unit off ebay, dude looks pretty involved with his rebuilds. That nor the old one makes any difference. Started probing some wires on the mode door since I was going to mess around with the blend door again until I knew something a bit more and nothing stands out.

After the BCM swap I really thought I was A-OK, couldn't believe it is still doing it. It is just so strange that no matter what, the calibration will have both actuators fully functioning, i can literally feel the temp and direction each and every time. It just will not take any commands for temp or direction unless I find that weird off/on sweet spot where it starts taking commands. That is why I thought the BCM was the cake. I didn't replace the fuse panel, just the BCM and moved my RKE (maybe that could be an issue?) over.

I can't find any relays that relate or anything, bit lost on it. I had a nice alldata printout of the diagnostic chain, don't have a DRB III to test with. I have access to an OBD pass through and a laptop I could nuke to build a form of DRB III if it works that was, similar to ford wds etc etc. But all that just to get the capability to manually command the actuators seems like a stretch...for whatever reason the modern snap on scanners don't have that command. I'm just so far away from bugging with the actuators anymore since they take movement with doing a calibration - I do find it interesting though someone mentioned one time they take a different voltage during calibration.