I just replaced the mode actuator yesterday, and found the write-up "Replacing HVAC Mode Acuator" on the TrailblazerSSforum to be extremely helpful, especially the pictures of how the two gears fit together. I'd post a link, but I don't have 5 posts here yet.
HVAC Mode Actuator door replacement
I just replaced my mode actuator due to the dash vents not working; it wasn't too bad of a job; you just need to be patient and smart as you work.
First you need to find out what part number to order; just call the local GM dealer. you will need to give them your VIN; the P/N I used was 89018675 and I got it from parts4chevys. $46.33 which was a lot cheaper than the dealership.
Remove lower dash covers. The actuator is located behind the middle portion of the dash; if you lay on the floor and look to the left you will see it.
Remove gray air duct as shown in pc #53; just pull it from its endpoint; this way you can get to the actuator better.
There's 2 actuators; you want the one with the white gear coming out the side; it's the lower one in pic #52. You will need a 5.5mm socket to get the 2 screws out; be careful not to drop the screws; take your time.
Pic #46 shows the actuator; the two horizontal holes are where the screws mount; the other one close to the wire connection has a dowel that helps locate the actuator. You will need to adjust the white gear shown in pic #46
to be at the same location as the gear on the actuator you removed in order for it to go back in correctly. There are 3 marks on the back of the plastic housing (as seen in pic #46) and also slots in the metal part of the gear drive, the top slot is in the 1'oclock position in pic #46. Be sure your new actuator gear position matches the old and it will drop right in. I put the screws in the socket and then wrapped electrical tape around them so the screw wouldn't fall out during assembly. The whole thing took me 45 minutes.
The vents now work like a charm and I saved a bunch of coin!
You can doooo eeeet!
First you need to find out what part number to order; just call the local GM dealer. you will need to give them your VIN; the P/N I used was 89018675 and I got it from parts4chevys. $46.33 which was a lot cheaper than the dealership.
Remove lower dash covers. The actuator is located behind the middle portion of the dash; if you lay on the floor and look to the left you will see it.
Remove gray air duct as shown in pc #53; just pull it from its endpoint; this way you can get to the actuator better.
There's 2 actuators; you want the one with the white gear coming out the side; it's the lower one in pic #52. You will need a 5.5mm socket to get the 2 screws out; be careful not to drop the screws; take your time.
Pic #46 shows the actuator; the two horizontal holes are where the screws mount; the other one close to the wire connection has a dowel that helps locate the actuator. You will need to adjust the white gear shown in pic #46
to be at the same location as the gear on the actuator you removed in order for it to go back in correctly. There are 3 marks on the back of the plastic housing (as seen in pic #46) and also slots in the metal part of the gear drive, the top slot is in the 1'oclock position in pic #46. Be sure your new actuator gear position matches the old and it will drop right in. I put the screws in the socket and then wrapped electrical tape around them so the screw wouldn't fall out during assembly. The whole thing took me 45 minutes.
The vents now work like a charm and I saved a bunch of coin!
You can doooo eeeet!
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Just completed mode door actuator replacement
Thanks to the knowledge shared in this thread, I felt pretty confident going in. Job was pretty straight forward & went smoothly. It helps if you are not in a hurry and can get yourself off the floor of the vehicle to stretch once and a while!
The actuator was firmly on the mode door shaft and I was reluctant to lever too much on it for fear of bending or breaking the shaft. I ended up fabricating a tool from some 1 1/2 square tube I had in the garage... made the removal really easy.
I also pulled the old actuator apart and couldn't see any visible failure... I presume the motor or cicuit board failed.
Thanks to the knowledge shared in this thread, I felt pretty confident going in. Job was pretty straight forward & went smoothly. It helps if you are not in a hurry and can get yourself off the floor of the vehicle to stretch once and a while!
The actuator was firmly on the mode door shaft and I was reluctant to lever too much on it for fear of bending or breaking the shaft. I ended up fabricating a tool from some 1 1/2 square tube I had in the garage... made the removal really easy.
I also pulled the old actuator apart and couldn't see any visible failure... I presume the motor or cicuit board failed.
I had a problem last week with my drivers side only blowing out hot air. I went and replaced the driver's side blend door actuator and now it goes from hot and cold when the dial is turned.
However I can't get the air to vent on the floor when it's selected. When I select floor it blows out by the windshield. The defrost/windshield and vent only work but not the floor. Is that an actuator issue? I see two other actuators above the gas pedal and I see one moving when I select the different modes.
However I can't get the air to vent on the floor when it's selected. When I select floor it blows out by the windshield. The defrost/windshield and vent only work but not the floor. Is that an actuator issue? I see two other actuators above the gas pedal and I see one moving when I select the different modes.
Are the actuators different from each other?
Are each of the actuators different? Or can i buy multiple ones and use it to change each one in my 03 Chevy Trailblazer?
Are each of the actuators different? Or can i buy multiple ones and use it to change each one in my 03 Chevy Trailblazer?
I replaced the actuator but still doesn’t move through modes , now instead of it being stuck on floor it’s currently stuck on the face vents
I just replaced my mode actuator due to the dash vents not working; it wasn't too bad of a job; you just need to be patient and smart as you work.
First you need to find out what part number to order; just call the local GM dealer. you will need to give them your VIN; the P/N I used was 89018675 and I got it from www.parts4chevys.com for $46.33 which was alot cheaper than the dealership.
Remove lower dash covers. The actuator is located behind the middle portion of the dash; if you lay on the floor and look to the left you will see it.
Remove gray air duct as shown in pc #53; just pull it from it's endpoint; this way you can get to the actuator better.
There's 2 actuators; you want the one with the white gear coming out the side; it's the lower one in pic #52. You will need a 5.5mm socket to get the 2 screws out; be careful not to drop the screws; take your time.
Pic #46 shows the actuator; the two horizontal holes are where the screws mount; the other one close to the wire connection has a dowel that helps locate the actuator. You will need to adjust the white gear shown in pic #46
to be at the same location as the gear on the actuator you removed in order for it to go back in correctly. There are 3 marks on the back of the plastic housing (as seen in pic #46) and also slots in the metal part of the gear drive, the top slot is in the 1'oclock position in pic #46. Be sure your new actuator gear position matches the old and it will drop right in. I put the screws in the socket and then wrapped electrical tape around them so the screw wouldn't fall out during assembly. The whole thing took me 45 minutes.
The vents now work like a charm and I saved a bunch of coin!
You can doooo eeeet!
I just replaced my mode actuator due to the dash vents not working; it wasn't too bad of a job; you just need to be patient and smart as you work.
First you need to find out what part number to order; just call the local GM dealer. you will need to give them your VIN; the P/N I used was 89018675 and I got it from www.parts4chevys.com for $46.33 which was alot cheaper than the dealership.
Remove lower dash covers. The actuator is located behind the middle portion of the dash; if you lay on the floor and look to the left you will see it.
Remove gray air duct as shown in pc #53; just pull it from it's endpoint; this way you can get to the actuator better.
There's 2 actuators; you want the one with the white gear coming out the side; it's the lower one in pic #52. You will need a 5.5mm socket to get the 2 screws out; be careful not to drop the screws; take your time.
Pic #46 shows the actuator; the two horizontal holes are where the screws mount; the other one close to the wire connection has a dowel that helps locate the actuator. You will need to adjust the white gear shown in pic #46
to be at the same location as the gear on the actuator you removed in order for it to go back in correctly. There are 3 marks on the back of the plastic housing (as seen in pic #46) and also slots in the metal part of the gear drive, the top slot is in the 1'oclock position in pic #46. Be sure your new actuator gear position matches the old and it will drop right in. I put the screws in the socket and then wrapped electrical tape around them so the screw wouldn't fall out during assembly. The whole thing took me 45 minutes.
The vents now work like a charm and I saved a bunch of coin!
You can doooo eeeet!
Thanks, very detailed description. I will try.
I am installing as actuator and it seems like during the install it wanted to go in with the door closed , is this right ?
The actuator gear does not move and I was wondering if this is middle or the close point , Please help I want to get this completed.
HVAC Heater Blend Door Actuator on a 2004 envoy
The actuator gear does not move and I was wondering if this is middle or the close point , Please help I want to get this completed.
HVAC Heater Blend Door Actuator on a 2004 envoy
Hi newer owner of an 02 Olds Bravada here. My HVAC is stuck on defrost, but can also blow out of the dash if I desire. Dual zone temperature controls still work but I have only the faintest breeze on my feet. Following this forums advice I tried resetting the hvac fuse, no luck, and I just put a new mode actuator in, still no luck. I may be too late to this party but if anyone can help me you guys can. SOS!
no if it clicks that means the motor is working it clicks cuz the cogs are damaged inside the acuatorWhen the motor goes bad does it cause a clicking sound?
Did you try the reset again, and perform the recalibration procedure, after replacing the actuator?Hi newer owner of an 02 Olds Bravada here. My HVAC is stuck on defrost, but can also blow out of the dash if I desire. Dual zone temperature controls still work but I have only the faintest breeze on my feet. Following this forums advice I tried resetting the hvac fuse, no luck, and I just put a new mode actuator in, still no luck. I may be too late to this party but if anyone can help me you guys can. SOS!
That seems like it would be my next step. I have the same issue, I just haven’t got around to fixing it.
Sent from my iPhone using Tapatalk
Did you replace the correct actuator?Hi newer owner of an 02 Olds Bravada here. My HVAC is stuck on defrost, but can also blow out of the dash if I desire. Dual zone temperature controls still work but I have only the faintest breeze on my feet. Following this forums advice I tried resetting the hvac fuse, no luck, and I just put a new mode actuator in, still no luck. I may be too late to this party but if anyone can help me you guys can. SOS!
Sent from my iPhone using Tapatalk
That's what happened with my 2002 trailblazer LTZWhen the motor goes bad does it cause a clicking sound?
MAY03LT,Great write up! This is one of my favorite tips too
I really enjoyed all of the YouTube videos and how to's through the years..very educational, and even in the most confusing times for me, sometimes you kept me laughing..I want to thank you for the knowledge you gifted me and the help to keep me patient..You're truly amazing, THANK YOU..!!
Man the old days of floor vents and blending doors on a cable and a mixing damper to the heater core. Things were so much more reliable and simple. just fixed my fan resistor harness. Kept falling out. No fan. Now… onlry auto defrost.I just replaced my mode actuator due to the dash vents not working; it wasn't too bad of a job; you just need to be patient and smart as you work.
First you need to find out what part number to order; just call the local GM dealer. you will need to give them your VIN; the P/N I used was 89018675 and I got it from www.parts4chevys.com for $46.33 which was alot cheaper than the dealership.
Remove lower dash covers. The actuator is located behind the middle portion of the dash; if you lay on the floor and look to the left you will see it.
Remove gray air duct as shown in pc #53; just pull it from it's endpoint; this way you can get to the actuator better.
There's 2 actuators; you want the one with the white gear coming out the side; it's the lower one in pic #52. You will need a 5.5mm socket to get the 2 screws out; be careful not to drop the screws; take your time.
Pic #46 shows the actuator; the two horizontal holes are where the screws mount; the other one close to the wire connection has a dowel that helps locate the actuator. You will need to adjust the white gear shown in pic #46
to be at the same location as the gear on the actuator you removed in order for it to go back in correctly. There are 3 marks on the back of the plastic housing (as seen in pic #46) and also slots in the metal part of the gear drive, the top slot is in the 1'oclock position in pic #46. Be sure your new actuator gear position matches the old and it will drop right in. I put the screws in the socket and then wrapped electrical tape around them so the screw wouldn't fall out during assembly. The whole thing took me 45 minutes.
The vents now work like a charm and I saved a bunch of coin!
You can doooo eeeet!
OK. So, on my 2004 XUV with auto-ac, disassembled dash to inspect actuators. See 3, bottom 2 look within limits (3 marks), but top 1 (Defrost?) is WAY outside (read: horizontal). Multiple recalibrations haven't worked. So... How'd it do that? But more importantly, can it be easily fixed? Eg. Remove actuator, move door within limits, replace actuator? Exactly what needs to be disassembled to do so. What's with the 5.5mm socket I read about, do I need 1, and if so, where can I get 1. Thanks
Oops... Forgot to mention no air through dash, no full defrost or floor mode... only a weak blend of defrost & floor. Rear a/c is fine. Switch next to fill port on canister by firewall leaks neon yellow/green liquid. Doesn't seem to hold a charge.OK. So, on my 2004 XUV with auto-ac, disassembled dash to inspect actuators. See 3, bottom 2 look within limits (3 marks), but top 1 (Defrost?) is WAY outside (read: horizontal). Multiple recalibrations haven't worked. So... How'd it do that? But more importantly, can it be easily fixed? Eg. Remove actuator, move door within limits, replace actuator? Exactly what needs to be disassembled to do so. What's with the 5.5mm socket I read about, do I need 1, and if so, where can I get 1. Thanks
Yes --- you will need the 5.5mm socket --- get two or three --- make sure they are 6-point and get at least one short one and a long (deep) one.OK. So, on my 2004 XUV with auto-ac, disassembled dash to inspect actuators. See 3, bottom 2 look within limits (3 marks), but top 1 (Defrost?) is WAY outside (read: horizontal). Multiple recalibrations haven't worked. So... How'd it do that? But more importantly, can it be easily fixed? Eg. Remove actuator, move door within limits, replace actuator? Exactly what needs to be disassembled to do so. What's with the 5.5mm socket I read about, do I need 1, and if so, where can I get 1. Thanks
NAPA has them as do a lot of other parts stores --- and of course: tool trucks. The 5.5mm is a GM idea and it's to keep the fasteners small and to keep amateurs away and outta them.
All of your new 5.5mms should be 1/4" drive because you won't be able to use 3/8" or 1/2" drive stuff under a dash anyway.
"Recalibrating" is usually death on these old actuators. They have plastic gears which were questionable when they were new --- now at a much older age, they snap off teeth whenever you ask them to recalibrate --- or you disconnect the battery to perform some other witchcraft or "resetting" procedure --- which just kills the old plastic gears inside, like I said.
As far as "easily fixed"? Nope --- you need the hands of a surgeon, eyeballs on your fingertips and another wrist somewhere between your first one and your elbow --- just to reach that one.
That's why the warning of never disconnect the battery nor perform a "recalibration" to them is so firmly stated.
Don't do it.
Neon green is either Martian blood or a dye that's been injected into your AC Freon pressure circuit to find a leak. Obviously --- you've now found the leak.Oops... Forgot to mention no air through dash, no full defrost or floor mode... only a weak blend of defrost & floor. Rear a/c is fine. Switch next to fill port on canister by firewall leaks neon yellow/green liquid. Doesn't seem to hold a charge.
I find it strange that the HVAC system didn't default to FULL DEFROST, as that's a NHTSA Federal rule for all autos made after somewhere around the change of last century --- assuring that, at the least, you can see out of the windshield even if you can't get warm or cooled.
The windshield was the airflow/defrost priority -- not human comfort.
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