dash air

[Jobber]

I have a 2000 National tradewinds 7350. Does anyone have dash schemitcs. My dask air/heat and vents only lets air out through the defroster.

[TXiceman]

Sounds like the damper doors are not moving to direct the air to the correct vents. These are either moved mechanically or pneumatically (vacuum). If your coach is a diesel, it should have a separate vacuum pump to operate the A/C doors. If a gasser, it will have a vacuum canister to store the vacuum from the engine.

You will need to track down the vacuum source and then work your way down the tubes to see where is is going astray. The vacuum lines should all go to a common block with the controls attached.

First look for a broken line of a stuck damper door.

And welcome to iRV2.

Ken

[Jobber]

I have a diesel< 300HP cat

[Jobber]

I will look for a vacuum line to it

[lkauk]

Check the fuse on the driver side plastic panel next to your knee. There is a 20 amp fuse that controls the dash blower controls and mine blows regularly. I don't know why the fuse blows, but I keep a supply handy and just stick one in when it blows.

[WSRG]

Almost all of the dash a/c and heaters are the same design. The fact that the air is only comming out of the defroster ducts usually means that the system has lost its source of vacuum. With a gasser, it is almost always a broken or disconnected vacuum line from the engine. With a diesel, it could be a defective vacuum pump, as well as a problem with a vacuum line. The only thing that the heater and a/c fuse controls is the blower motor, a/c compressor, and the heater control valve [if there are wires running to it]. The heater and a/c mode doors are ALL controlled by vacuum.

Hope this helps

Bill

[garym114]

If you do not have vacuum to control the dampers the fail position is to discharge the air to the defrost vents. Find out where the vacuum is supposed to come from on your coach.