No heat?

Could you please tell me where the bleeder screws are?

06 chevy uplander frt heater dont work back does

Auxiliary heater in rear blows cold. Flushed auxiliary heater and coolant flows freely through it. Heat in front works fine. Need guidance on if there is a valve the prevents heat from going to the rear that may not be opening.

We have a 2005 uplander with hot air heater problems. Start the vehicle for the 2nd time. No hot air, vent selector switch working(set on hot), blower motor switch is working, engine temp good, coolant good, fuse good. When changing functions we could here the switching. Played wtih fan switch and heater switch. Turn van off. Restart play with switches again. All of sudden heat enters the cabin. Happens every 3rd or 4th time the vehicle is used. Taken to dealership. Everything checked out electrically when the heater is operating normally. They suggested replacign the thermostat. Issue did not go away. This can be an expensive endaveour to route casue the issue. I am in contact with the electrical engineer from GM on the program. I post what he finds out regaqrding this issue.

Found the solutuion to the problem. There is a software issue with HVAC module may be exhibiting "Temperature Door Drift". The result of the investigation was a new release of software for service into GM SPO.

Problem statement: GM 2005-2006 Minivan vehicles while operating in full cold mode, the discharge temperature of the supply air stream is not sufficiently cold enough. The rear air stream was operating at design capacity, and blower speed did not affect the overall temperature of the discharged air. As a result of testing it was found that the temperature door within the front HVAC module was exhibiting a “float” condition, where full cold operation was not being achieved.

Drive Complete: When a singular drive (damper actuator) completes, there is a check sequence built into the logic of the control head that looks for any overshoot from the target destination. If there is an overshoot condition, the software will update the current position as the original target position, therefore avoiding and “hunting” by the damper.

These two logic paths (executed within the control head software) operate at different rates. The target update task is executed and checked at a rate of 20ms, while the drive complete task occurs every 100ms.

Root Cause: “Any time the temp knob is turned, there is a chance that an intermediate value can be read and acted on.”

I'm also having a problem with my front heater. The heater seems to be cycling in the outside air when the revs go below 2000rpm. If I'm parked, and rev the engine, I can hear the flap close and I get warm air again. This has become an issue since the outside temp yesterday was -35. By the way, the chevy uplander is an excellent cold starter.

The manual says that the outside air shouldn't cycle if the temp is below +32.

So, can you tell if your uplander is cycling air from the outside or inside?

This guide can help as well

https://www.2carpros.com/articles/car-heater-not-working

Let me know

I had this problem the guide shows me the coolant was low because the radiator was leaking.

My sister's car. Antifreeze looks decent, blower motor works, but no heat. Problem may have developed suddenly or over 2.3 weeks gradually, not sure. Acts like plugged heater core or valve in coolant line not opening. Are heater hoses easy to touch, to feel temperature? If so, where? Anything else to be checked? Is valve electric or vacuum actuated? My sister has bad arthritis and must rely on others.

Thanks, very helpful. Hoses near firewall feel about same temp as upper radiator hose. Owners pamphlet says one fuse block (of 2) is on passenger side under instrument panel. Cannot find looking under glove compartment. Ditto on RH side above accel pedal. Is the "instrument panel" something other than the dashboard?

The 1st fuse box is on the very end of the passenger side instrument panel, you have to fully open the door to get at it. The 2nd is under the hood on the passneger side in the black bos that has the jumper peg sticking out.

Thanks. The 1st sounds like the way Generous Motors located a fusebox on my Chev 2002 Silverado 2500HD (except maybe for right vs left). Appreciate your help!

Steam was coming out under hood. I took it to a repair shop. They applied pressure to find leak. They cut off part of hose that was damaged then reapplied the hose. On my way home temperature went all the way to hot then computer said hot going to air condition mode( I think, I was driving). It was blowing and is now blowing cold air when it supposed to blow warm air. Do you think maybe mechanic didn't put enough fluid back in?

Thank You!

My heater wont work air is fine someone told me could b actuator heat blows just wont heat up but van runs normal as far as temp. What could I do fix this