Silverado HVAC problem

My 99 silverado blows air through the dash vents only. No matter what mode I choose on the contol it blows through the dash vent. It will not blow through the floor vents or the defroster. When you move the switch, there is no noise. The fan switch works fine as does the recirculate/fresh air switch and the A/C switch.

Anyone have any ideas or help?

Reply to
Erik
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Silverado HVAC problem Group: alt.trucks.chevy Date: Thu, Oct 23, 2003, 7:39pm (CDT-2) From: snipped-for-privacy@hotmail.com (Erik) My 99 silverado blows air through the dash vents only. No matter what mode I choose on the contol it blows through the dash vent. It will not blow through the floor vents or the defroster. When you move the switch, there is no noise. The fan switch works fine as does the recirculate/fresh air switch and the A/C switch. Anyone have any ideas or help?

Your settings should be controled by vacuum. Pull your control panel ...Make sure the vacuum lines are hooked up.. we will start from there Steve C.

Reply to
Steve Cook

Do you mean the panel where the fan, temperature, mode, ac, etc switches are. If so, there are no vacuum lines hooked to it. It has two electrial harnesses. I took it out/apart and hooked a multimeter up to the mode switch. I got resistance readings that increased/decreased as I moved the switch.

If your are referring do something else, let me know where to find it.

Thanks for your help, Erik

Reply to
Erik

Look uder your dash above your gas pedal..You should see an actuator hooked up to 2 hvac doors... make sure nothing fell off, then inspect the actuator..if memory serves me thats simply a 3 wire one.. power and ground, then a varying voltage from the control head ..kinda like a servo on a rc car... as long a you have all 3 change the actuator... Bobo

Reply to
Bobo

Re: Silverado HVAC problem Group: alt.trucks.chevy Date: Sun, Oct 26, 2003, 6:56pm (CST-2) From: snipped-for-privacy@hotmail.com (Erik) Your settings should be controled by vacuum. Pull your control panel ..Make sure the vacuum lines are hooked up.. we will start from there Steve C. Do you mean the panel where the fan, temperature, mode, ac, etc switches are. If so, there are no vacuum lines hooked to it. It has two electrial harnesses. I took it out/apart and hooked a multimeter up to the mode switch. I got resistance readings that increased/decreased as I moved the switch. If your are referring do something else, let me know where to find it. Thanks for your help,

Erik

OK I had one to day same symptoms ended up being a bad control head.....Thats where you switches are....This year some have vacuum controlled heads some have electrical like your is why i asked... Steve C

Reply to
Steve Cook

Thanks Bobo,

I got the actuator out last night. What a Biatch! I am going to call around for some pricing. I hope I can get it back in.

Reply to
Erik

Reply to
Bobo

More problems.

I picked up the new actuator yesterday. While I was still in the dealership parking lot, I plugged it in. The actuator turned and I was extremely happy. However, later that day I went to install it. I plugged it in to set it at the default. It doesn't turn at all. I am now so frustrated, I am about to take it to the shop. Actually, they can't get to it until next week so that gives me a couple of days to tinker with it.

  1. Is there some other sensor/logic that would keep it from turning?
  2. Is there anyway that I could have blown the new one up by hooking it up?

I have checked the fuses and they are all good.

Any ideas?

Thanks

Reply to
Erik

================================= Maybe you can clean the control switch with electrical cleaner............?

Reply to
Scott

Check what kind of voltage readings you get at another actuator, my 96 has the fresh air actuator on the far left under the dash. Then see if you are getting the same at the one you are working on. If not then you have an electrical issue. Mike

Reply to
Mike Copeland

I went home at lunch time and plugged the actuator into my wifes tahoe. Didn't work. The tahoes mode door works fine after plugging it back in ( whew! ). I came back to work with my old actuator and took it apart. I noticed on the new one that it may have moved in one direction too far. I was thinking maybe the sensor was out of range. It seems like the mounting bolt acts as a stop in one direction and the actuator was a bit past it. So, I took it apart and carefully pulled the top gear off, and moved it back a little bit. I plugged it back in my truck and shazaam! It works!

Maybe I won't have to take it to the shop after all.

Ok,

Now a couple more questions.

There looks like there are 2 doors. One controls the dash vent and the other controls defrost/floor. The default on the dash vent seems to be open. However, it looks like to install the actuator I have to close the dash vent otherwise I don't think I can get it in there. Does this sound correct?

Also, when I install it does the last tooth on the actuator rest on the last tooth on the vent door arm or is it overlapped? If it is not overlapped then it would seem that I could set the actuator about midway, install it and then turn the switch to defrost and it would match it self up. Otherwise, I am going to have to set the actuator on defrost, and try to overlap the teeth when I install it.

Thanks for all the help

Erik

Reply to
Erik

Thanks guys for your responses. I got the actuator in tonight and everything works fine. I don't know what a shop would have charged, but I fixed it for the $60 actuator.

Thanks again,

Erik

Reply to
Erik

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