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Envoy HVAC Mode Actuator

37K views 10 replies 10 participants last post by  richardr 
#1 · (Edited)
Folks,

First, I've got to say this is the best automotive enthusist site I've ever seen. The amount of information available and the community involvement is by far the best that I've encountered in the Internet.

Having said that, I'm hoping to get a few questions answered about the dreaded HVAC Mode Actuator (one of many problems I've had lately). I took the vehicle to the head service tech (a friend-of-a-friend) at the local GMC dealer who agreed with my assessment--it needs replacing.

I've tried what other folks suggested: pull the HVAC-B fuse for 10+ seconds, put it back in, start the car and not touch the air system for at least 40+ seconds. After that failed, I did what the service tech told me over the phone: remove BOTH terminals of the battery and touch them together for at least 15 seconds. He said doing so would drain all transient charges in the vehicle. Unfortunately, that didn't work. When I took my 2004 Envoy XL to him, he put a code scanner on it and read the codes; sure enough, the HVAC mode actuator code was stored (the code was B0263). He tried to force a recalibration with his diagnostic scanner, but it failed. Net result: the actuator is dead.

I've read many, many posts about this problem and how to replace the actuator, but all of those posts were for the Trailblazer. My Envoy has automatic temperature control. I'd imagine the design of the Envoy HVAC system is similar to the TB/Rainer, but does anyone know that for certain?

In other posts for TB's, I've seen a rough procedure of: remove the two lower dash panels from the driver's side, remove the floor vent tube, and the actuator can be removed. Anyone know if this will work for an Envoy? I've removed the two lower dash panels, but couldn't figure out how to remove the vent tube. In all hosesty, I didn't have a replacement part with me, so I didn't put that much effort into removing the vent tube.

Finally, does anyone have the correct name and/or part number of the HVAC Mode Actuator for an 04 Envoy with ATC? I've searched GMPartsDirect.com but couldn't find it.

When I take a stab at replacing the actuator, I am going to take step-by-step pictures and post them for folks that have this problem in the future.

Thanks again for all the help, folks. This site has certainly saved me hundreds already, and I've only been a member for a few days ...

Pete
 
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#2 · (Edited)
Welcome to site...
Maybe this will help...

MODE ACTUATOR here is a earlier post.....


Originally Posted by tasnat23 View Post
well i went to the dealer to get mine fixed finally... they told me it would take 3 hrs, even with the TSB...

so i bought the part. me not knowing much about installing this part, it took me ONE HOUR!!!! how ridiculous!!!! so it cost me 55 bucks, for the part. so if any of you need a how-to to install this part... give me a holler... ill let you know...

all you need is a 9/32 socket, and a 7/32 socket. take off the lower panels on the driver side....take out the left floor vent tube, and look straight up. easy as that. you dont even have to be a contorsionist to get it out

hope this helps some of you, also the part number is
ACD# 15-73596 GM#89018675

.....Read the above this may help...may be a short cut or two here... hope it helps.....

Remove left lower driver vent tube.... Its held on by a plastic grommet like on the door panel, on the vent tube through a hole on the fire wall mount, just left of the steering wheel shaft.. Just use a long flat screw driver and pry it out/loose and remove the tube. Then look up at the top beside of the blower outlet and you will see the mode actuator. One for the defrost and the other for the floor/dash blower. The one for the defrost is closest to the defrost/windshield.........
 
#4 ·
Doesn't matter TB/Envoy. My Denali had the same issue when I had a shop install a remote start and disconnected the battery to do the work. I have auto temp and selector.

My dash vent motor took a holiday and I needed to replace it. 2-3 hours and some contortions and it now works very well. I even replaced the old battery and the new unit starts right up, searches for its new end position and doesn't self destruct upon resetting itself.

There are several pictures of the units on this site, just use search and type in "mode actuator" and you will come up with lots of pics and helpful suggestion. I took out my drivers seat so I could lay on a flat floor, since I was going to be there for more than a few minuets.
 
#6 ·
dash vents dont work

Well the wife has had it! No cold air out of the dash vents when it is 100+ outside. I could really really use a very detailed description on how to fix my problem. I have tried to find a vaccum line and have eliminated that and tried to diconnect the battery and that did nothing as well. Please let me know:thx
 
#7 ·
Well the wife has had it! No cold air out of the dash vents when it is 100+ outside. I could really really use a very detailed description on how to fix my problem. I have tried to find a vaccum line and have eliminated that and tried to diconnect the battery and that did nothing as well. Please let me know:thx
There's a much longer thread about the mode actuator. Did you follow the advice in post #4?

PS No vacuum lines. They're all electrically actuated.

If not, here it is:

http://forums.trailvoy.com/showthread.php?t=40235
 
#9 ·
I'm give what I've got so far, as the saga continues....

Ok, sounds like you need part no. 89018675 actuator. You have to drop the 2 lower dash panels on the drivers side(7mm hex screws). Then if you lie on your back under the dash, with a good light you will see 3 actuators. Unless your hands are small, you won't be able to remove them. The 1 you want is the middle 1. They are held in with 7/32 hex screws. I got 1 out. It might help if you remove the knee bolster, and the screw holding the big wire harness. Let me know if you succeed, because I spent 5 hours yesterday in a garage for equipment, and I couldn't succeed. I'm a turf equipment mechanic. I think you may have to remove the gas pedal asm.
 
#11 ·
Witch Actuator is witch have 3

Happy Sunday I have a 2004 GMC envoy my left side vent was blowing warm my right side vent was blowing cold I did a reset by taking the fuse out I put the fuse back in and now both vents arent working I'm in sunny Florida it was 96° yesterday with the index which of the Actuators Which one of them do I replace
Also what started all of this was my air Was blowing cold for 10 minutes 15 minutes then get warm
I would like some advice on which one to me please please
Richie
 
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