Interior Fan Motor Slows Down Or Almost Stops

[chuckconnie]

Any ideas on why, when I start to ascend a hill my air and heat blower almost stops ?

It is a 2002 30 foot Winnebago Sightseer on a Ford chassis. It should not be from the alternator dropping RPM's due to the climb because the engine RPM's increase because of it down shifting.

HELP

[rossboyer]

You probably have vacuum controls for your heating and cooling. When climbing a hill the vacuum decreases enough for the controls to change position vs. where you had them set.

[wolfe10]

Correct. Please check, but I suspect that the fan has not quit, but that with loss of vacuum, it is coming out the default position-- the defrost vents.

Check for a vacuum leak or add a larger vacuum reservoir are in order.

[dickandlois]

Chuck,

Looking for information regarding the vacuum system mentioned in the first 2 reply's.

Ford uses plastic lines for the vacuum system and over time they can deteriorate. Plastic gets brittle over time and can also deform or melt should the temperature get to high.

At the front Right of the engine, look for a block with White, Red and black lines connected to it. One of them goes to the Vacuum reservoir from the information I have been able to dig up.

Should one of the vacuum lines fail the blower system would go the default Brett mentioned.

With the loose of vacuum you should notice a difference in the performance of the engine. If you have access to a code reader, there should be a code set, that indicates loose of vacuum.

If you have a check engine light, the loose of proper vacuum could be the cause of the check engine light.

Rich.

[chuckconnie]

Thanks. Will try to check lines and the default setting.

[wolfe10]

You might start by just putting your hand over the defrost vent the next time this happens. The default position IS defrost. So if that is where it comes out, the next step is to check for a loose or broken vacuum line.

Brett