Hello
I have a 2000 Express van. There is no air coming out of front dash vents only getting air to windsheild and floor. Temperature controls work.. Suspect this to be a blend air acuator problem but cant locate where it is.
Any help would be very appreciated..

 

Above and to the right of the doghouse I think....Its an electric servo, not vacum like the older vans.....

 

I found the one above the doghouse to the right. This one seems to be working properly. It controls the heat cold function. There must be another one somewhere behind the dash.

 

On my 2014 the selector **** which controls where the air is output is part of a vacuum system. Tubes are just above the passengers feet, visible by pulling the floor mat back.

 

Electric? I wish! Are you sure about that? Whenever I have hard acceleration or am pulling a steep hill my vents automagically shut down & you can hear the vacuum servo as the engine is losing vacuum... when you let off the gas (or top the hill) they automagically return to the dash settings. It's a real annoyance when you're climbing a long, steep grade and your AC stops blowing on you then switches over to cooling dead bugs in the defrost vent.

Are some models electric & others vacuum? I'd gladly raid the salvage yard & convert mine to fix this annoyance.
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From my experience with GM vehicles and the 2000 Chev Express I own now, I'd bet that your dealing with a vacuum system. In the late 80's there were some models that used electric servos to control the air dampers. These models had a digital display and automatic temperature controls. My newer Buick LaCrosse has a completely automated climate control system, so all of the dampers are electric. GM has had a strange obsession with using vacuum actuators. I had an '85 Chev Van with a 6.2 diesel and there was a vacuum pump that ran the climate control system. Oddly enough the automatic hubs were operated by vacuum back in the 80's and 90's, I haven't owned a GM 4WD for many years, so I don't know what they use now. I'd check the vacuum lines first. They run from the back of the controls over to the right and connect to their various actuators. I'm not 100% sure, but I'd bet the damper that lets air into the dash vents is above the dog house. On the 2000 Express I just bought, my vacuum lines were just loose under the dash and were unprotected. I carefully bundled them and put that plastic split flexible tubing on them to protect them. I'd start checking there for leaks. The temperature control is also vacuum operated. As I was poking around in my engine compartment I noticed a black and brown pair of vacuum tubes connected to a valve in the heater hose lines. I've noticed that the lines are all colored, I wonder if there's a section in the service manual that has a diagram? I'd try googling it too to see what comes up. Good luck. Let us know how it goes.

 

You might look into getting an electric vacuum pump that runs on 12 VDC. Maybe that might be a solution?

 

Chevy Express 2500 Van A/C & Heater System Control Parts | Chevy Express 2500 Van Air Conditioning & Heating Controls | Chevy Express 2500 Van Aftermarket Air Conditioner & Heater Control Parts At 1A Auto

 

Thanks! I'll have to look and see if mine are similar & if there are connectors in the harness for them. The one made for rear controls is certainly electric - you can see the connector pins in the photo of the part. (Rear control... for conversion vans w/ rear vents??) Front one you can't tell from the pics if it is electric but part design looks the same as rear unit but with actuator on other side.

All I know is mine misbehaves when the engine is under load & you can hear the vacuum hiss, or what sounds like that, when the vents redirect the air flow from the control settings... after the load is reduced, they return so mine do function... it's just the design itself.

For the OP mp2140's responses sound right, maybe his vacuum lines are disconnected or damaged?

mp2140: Great idea! I'll look into a vacuum pump that I can hook into the system - if there is a vacuum reserve canister that would be the place to hook it in.
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Found bad vacuum line that attaches to the pcv valve I believe. Cut the leaking end off and reattached. Now have air coming out of front vents.