I have a 2002 newmar Dutch star gas burner. I am wondering if anybody has had the ac air blowing out the defroster. If so is it a vaccuume leak somewhere if so where is the lines located. I think the the vaccume pulls a door somewhere that changes from ac vent to defroster vent. Air blows cold out of the defroster vent

Yes the HVAC doors are vacuum activated, and the lines run right to the back of the dash A/C controls. But, the most common failure mode is by far a leak in the vacuum reservoir typically mounted under hood. It looks like a big black tin can usually with a single line going to it. but can be a spherical shape also. The system is setup to go to the defrost vents if control is lost to insure you don't frost/fog up the windshield which becomes a safety issue.

There was a problem on Ford Chassis around that year with an inadequate vacuum reservoir and was a recall years ago to replace the reservoir. If there is insufficient vacuum, the system causes the shutters to close to living area and default to defrosters so you will always have air to windshield. I had that on my 2001 Dolphin years ago.

Didn't know about the recall thanks......and also forgot about the old juice can under the hood...will start a Nader the hood...thanks for the quick response

Defrosters always use the AC to blow dry air.

DaveG39 wrote:There was a problem on Ford Chassis around that year with an inadequate vacuum reservoir and was a recall years ago to replace the reservoir. If there is insufficient vacuum, the system causes the shutters to close to living area and default to defrosters so you will always have air to windshield. I had that on my 2001 Dolphin years ago.I don't believe there was ever a "recall" for this problem. I do believe however there was a Ford service bulletin issued. Recalls involve safety items. The heat/AC system is designed to provide windshield coverage in cases where vacuum is lost, so there would be no safety issue.Service bulletin items are in many cases covered by the factory when the vehicle is under warranty. However I doubt they will still cover something on a 15 year old vehicle.On the bright side the problem is more often caused by the vacuum line being knocked off the reservoir port when service is performed (or when checking the oil level). The spherical tank should be located in the center of the vehicle right to left, and above the hood opening. You'll probably have to stick your head inside the engine compartment and look up. There should be a small diameter blue hose with a clear fitting that connects to the reservoir.There is also another vacuum reservoir attached to the frame just below the right headlight. This reservoir has nothing to do with the heater controls, but if the connector has come off or the tank is rusted out the engine may not be able to produce enough vacuum to supply the heater controls. Generally if this tank or connector fails it will turn on the "check engine" light. However I have seen cases where it didn't.

AC blowing out defroster | Good Sam Community

12 Replies

DaveG39
Explorer
Jul 11, 2017
There was a problem on Ford Chassis around that year with an inadequate vacuum reservoir and was a recall years ago to replace the reservoir. If there is insufficient vacuum, the system causes the shutters to close to living area and default to defrosters so you will always have air to windshield. I had that on my 2001 Dolphin years ago.
sch911
Explorer
Jul 11, 2017
Yes the HVAC doors are vacuum activated, and the lines run right to the back of the dash A/C controls. But, the most common failure mode is by far a leak in the vacuum reservoir typically mounted under hood. It looks like a big black tin can usually with a single line going to it. but can be a spherical shape also. The system is setup to go to the defrost vents if control is lost to insure you don't frost/fog up the windshield which becomes a safety issue.

Forum Discussion

AC blowing out defroster

12 Replies

About Motorhome Group

Related Content

Windshield defroster not blowing

Defroster workaround

Dash AC blows out of the defrost vents

all breakers blowing

Windshield defroster question