Hot Feet Fix

[T Man]

Reproduced from www.s-10crewcab.com (http://www.s-10crewcab.com/phpBB2/viewtopic.php?t=863&start=0)

Found this on GM's techlink forum:

quote: If you can find vacuum schematics a few years back you will see that they added a vacuum actuator to the case called a "slave" valve, it has a grey hose going to it from the control head.

BUT this is only supposed to exist with AUTO CLIMATE CONTROL!

A bad example is doc# 389165, it shows the hose and actuator I speak of but I can't find anything that shows operation for the "slave" door.

What happens on vehicles with C60 manual HVAC is that the door causes ambient air under pressure at the cowl to be forced through the heater core making it nice and toasty and cooking the driver's foot because the mode door rests in the "heat" position.

Open the glove box, lift up the wire hook and swing the door down. Now you will see right in front of you this actuator with the grey hose, take the grey hose off the vacuum actuator and stick a bolt in the end of it so it won't hiss or leak, tie it back so it won't rattle around and close the glove box.

You just fixed this concern, made the customer happy, flabbergasted your SM and if you think I am full of dookie, try all the other modes. They are TOTALLY unaffected by disconnecting that actuator, the heat is just as hot and the A/C is just as cold.

I think in the '96 manual comparing the vacuum scematics on C60 and whatever auto is on the utility you will see that the grey hose and the actuator are not supposed to exist on C60 manual HVAC vehicles.

I am not exactly sure what this "slave" door is supposed to do but I know when you turn the HVAC knob to Off it fries your feet.

I think someone sold them on the idea they could use one case for all units and neglected to mention that you'd have a few hundred thousand folks with burnt toes.

I thought TAC figured this out by now with someone's help I guess I never called and told them because I know how to fix it already.

I have done this to half a dozen customer's cars and they all leave happy as a lark. Call me nuts if you want but that's how to fix it and althought it is "normal" (because ALL of them do it) it's still wrong.

Found it...did it, it worked, nuff said.

I believe it is only for 98-05 s series

[87wildside]

Now go find it for the first gens.

[Mikz86TA]

Are you referring to the small diameter lt.gray vaccum tube that comes from the cluster of colored vacc tubes. Kinda goes to a vacc actuator centered behind the glove box? So there isnt any repercussions to do this...just no hot feet?

[T Man]

Yes, the small grey tube. I just did it to mine, and have maybe 10miles on the mod. BUT from what ive read it doesnt present any other problems

[T Man]

If you have the Auto climate controll the slave valve is needed, so dont do this mod

[Mikz86TA]

I got reg cab with C60 manual climate control....if youre hot, reach your hand over and turn the f**kin knob style =) hehehe I am going on assuption you pull the hose from the valve and plug the hose side.

[962dr]

my 96 Bazer is a foot fryer.My wife hates it so bad she wont ride in it.any ideas if this hose is present on it?

[plant.one]

has anyone found the 1st gen fix?

[TreasonAgainstCaesar]

Hey T Man, thanks for posting this. I had seen this before, but never got around to doing it last summer. Now that I really needed it again, I didn't have the info.

What I usually do is turn the setting to face & fan to lowest setting (off?), then close the vent doors. But this should only take a couple minutes and be better.

has anyone found the 1st gen fix?

I didn't think this problem existed in the 1st gen. At least I never noticed it during the 6 years that I drove my '93 Jimmy.

[Mikz86TA]

962dr...yours should be the same. Harder to get to since your glove box is different. But the vac tube color should be the same, and go to a similar diapragm.

[Mikz86TA]

I haven had a chance to do this yet and forgot about it. I got a huge Boston crossover in the way anyways. Ill get a pic up soon for a visual on what people are looking for. It should lower the ambient interior tems which should make the AC more efficient. On a side note......If anyone knows AC ducting well, I have a query. First is filtering. I know newer vehicles have a cabin filter and ours doesnt. Where would you put one if one were to devise a mod for it? Second is air freshening. I know some of the air comes in from the cowl. But on MaxAC there is interior air re-claimed and mixed. Where does the system get the re-claimed air from? The lower vents, is there another opening? I know on the TA, there is a flap and 4x6" opening at the passenger foot well, where the underdash cover is. I dont remember seeing ont in the truck.

[Tink]

Damn, I didn't see this thread a week ago - glad I caught it now. My 00 BlaZeR2 roasts me out!!

I'm with TreasonAgainstCaesar - my 91 does not and neither did the other first gens I've owned.

[T Man]

My 87 did this, but here is the problem. THis is only a fix for vehicles using the same ducting as the auto ac vehicles. I dont believe auto ac was an option for the 96's as well as anything older than that.

[Tink]

Just did mine, so I took a picture of the vacuum line while I was there.

[Mikz86TA]

I finally did this a week ago or so. To be honest the temp here is such that right now I havent noticed its effects. But I did notice one other thing. I was driving real early the other morining, had the AC off and the windows slightly open. It was a cool morining. I noticed a cold effect on my face and found myself checking the AC knobs to be sure they were off. I put the windows up and still felt it. Apparently the air from the cowl entring was blowing through out the vents. Didnt mind it, but it was kinda freaky since it had never done that B4.

[TreasonAgainstCaesar]

I actually did this a couple months ago. It seems like there is still hot air for a few minutes after I start driving if it's sat for a while, but otherwise, it was a lot better. I think I'll put it back once winter actually hits--I ziptied a bolt inside the line, so it will be easy to undo. Right now we're having 90* days...

[ILOUTFITTER]

Hey T Man, thanks for posting this. I had seen this before, but never got around to doing it last summer. Now that I really needed it again, I didn't have the info.

What I usually do is turn the setting to face & fan to lowest setting (off?), then close the vent doors. But this should only take a couple minutes and be better.



I didn't think this problem existed in the 1st gen. At least I never noticed it during the 6 years that I drove my '93 Jimmy.

its a GM problem not model specific, my 92 and 93 do it, my 99's did it and my classic GM's did it as well.

[TreasonAgainstCaesar]

Good time of year for a bump on this one. I had hooked mine back up to have hot feet for the winter, and I just switched it back to cool feet a few weeks ago.