I didn't mean to say dash. I meant when I have the wire up there to open the door, I still have some heat coming out of the defrost....

 

And I would still like to see what a good actuator looks like in operation. Mine wibble wobbles all around when going full floor to full defrost, and vice versa. But when I put it to mix it doesn't move at all. Looking forward to getting my new actuator so I can compare....

 

Thanks, thats the first I heard on sticking a screwdriver in the end. I got my new door the other day but havent really gotten a chance to look and see how that arm attaches. I do know it doesnt just pull off, I already tried that.

 

what could be a helpful diagram attached

 

Yes very helpful diagram. According to the bottom left, which I believe is the door that has broken, when in the up position blocks off airflow to the defrost duct.

 

That one broke on my first 05 jimmy , I cut a hole on the shaft side to get it out , fixed it with a pin and glue , put it back in and closed the hole with a piece of plastic.

 

Since you were talking about testing vacuum, I thought you might be able to assist further. I got the new parts in today. The new actuator (for defrost/heater door) definitely has more resistance, not loose like the old one. But when I hook up the vacuum lines, it still only goes to full out or full in. When I turn it to mix floor/defrost, the actuator doesn't move at all. I'm testing with it still loose from everything, so wondering if the spring tension on the link helps to move it to the mix position, or do I need to be looking for a vacuum leak? When the old one was on, mounted and attached to the link, it did try to move a little when I would put it on mix. But once I pulled it loose, it didn't move at all on mix, just like the new one. So again, I'm wondering if the spring tension on the link helps it move to the mix position. Hope that made sense!

Also, I do notice when I first start my Jimmy, the air always blows out of the dash vents for a few seconds, even when I left it set on floor from the previous drive. So I'm assuming I do have some leak down on the vacuum while vehicle is turned off. Is that just typical?

 

one actuator goes for defrost or floor
one actuator goes for upper air which has a slave unit as well
one goes for recirculate
look at the diagram above.

I want to say that startup behavior is normal. I'm sure somewhere there is an exact figure on how long it should hold vacuum but i don't have that # i have looked a little for it too. rule of thumb i have been using is it should hold vacuum for at least 30 seconds or so after shut down. that will account for a long duration of acceleration when the motor isn't making vacuum. so if you turn off the truck wait 10-15 seconds and change the vent position switch to another position you should hear it attempt to change. if you don't hear that you have a decent leak somewhere.

 

the diagram i attached above is in mix mode from what i can see, I assume the vacuum actuators have 2 or 3 positions depending on which actuator based on the diagram. in the case of the defrost actuator it appears to be resting/neutral, full vacuum + (all the way out) and full vacuum - (all the way back). the only one that has a partial movement beyond 3 positions is for temp as it's driven by an electric motor not a vacuum actuator. i honestly never looked at the actuator in floor/defrost mode. since i live in vegas i rarely ever have to use defrost. since i see an A/B/C position in the diagram i would assume that in floor/defrost mode i would assume the "resting position" of the actuator is floor/defrost mode, so it wouldn't move when set there. floor would pull it all the way back and defrost would push it all the way forward or vice versa. this is all theory based on the diagram that i assume to be correct.

I would guess the little movement you saw on the old one would be vacuum escaping when it shouldn't have been when it was set to mix mode rather than just staying in the center rest position. once again these are guesses based on the info i have and my past experiences since i'm not looking at what is actually going on.

 

My old and new actuator both are either full in or full out. It doesn't move or return to the center or rest postion when on mix floor/defrost. I watched a video online where the guy switched his from floor, to mix, to defrost. When it went to mix, the actuator arm would move about halfway out (or in, depending on where it started). So I really am still stumped on that.

I did try your test after turning the car off. Waited 15 seconds and then switched from floor to defrost. Also later tested from floor to dash. Both times it switched over after that 15 second wait time, no problem there. Then I tried switching back, and it does move, though not so quickly or completely. But if what you're saying is correct, I guess that's because I used up most of the vacuum when I switched the first time.

Anyway, it's supposed to be warmer the next few days, so hopefully I can work on it and update what's going on. I think you're right though, about replacing that dash actuator while I've got it torn apart already, because that one does seem a little slow. Plus the way it's always diverting to dash when first started. I'm thinking I may have a slow leak on that actuator. (I also read somewhere that default is to go to floor/defrost, so that you can have a clear windshield at least if everything goes to pot. So going to dash on default seems wrong.) I'll keep you posted. Thanks for your help!