plastic vacuum lines in 2003 Georgetown

[reddiver70]

Does anyone know where I could get charts on the vacuum hoses for a v-10 2003 Georgetown. I loose dash blower sometimes when I accelerate. Ventilation returns when the engine has reached when the accelerator is no longer getting the rv up to speed.

[CountryB]

Sorry can't help with the diagram, but probably know that you can replace the plastic hoses with the rubber hoses available at most part stores. The plastic will crack from age, and when they do, the situation you describe occurs (vent switches to defrost on acceleration). Usually these system have a vacuum storage canister (looks like a small coffee can or plastic ball with a nipple) check this hose too/first.

If you have access to the underside of dash, just tracing out the lines may reveal where the crack is. The line is probably still connected just cracked so a new rubber line will fix the problem.

[Waiter21]

I loose dash blower sometimes when I accelerate

Sounds like a vacuum leak.. When the vacuum leaks down, the mix doors close to the Defrost mode..

I used to own a 2001 Mirada. The vacuum lines in that vintage Coachman were the cheep colored plastic. Look behind the dash and inspect, tug on the vacuum lines a little. They get cur and broke very easily. I found broken (cut) lines under the dash. I also found the hose had fallen off of the accumulator under the hood, Its a plastic ball, about 3-4 inches in diameter, high on the passenger side under the hood

[MoCoTom]

IF YOUR SYSTEM WORKS AS IT SHOULD UNDER LIGHT THROTTLE, this is likely your problem. I had the exact problem you describe except I have a gas Workhorse chassis, but my guess is the vacuum climate control systems are very similar. Here is what I found. The vacuum reserve canister is placed in the system to supply a constant vacuum supply no matter what the demand is on the engine. This canister has a built in one way check valve so it can maintain the vacuum no matter what the demand is on the engine. It is not uncommon for the check valve to fail which allows the vacuum to drop as soon as you accelerate which intern shuts down your climate control vents. As soon as you back off the throttle the vacuum returns and climate control operation returns. Simple fix is buy an inline check valve and install it in the supply line between the engine and the canister. A good hardware store will have the check valve with female threaded inlet/outlet so you can use what ever size nipples need for your application.
Tom

[IggyTech]

Originally Posted by reddiver70

Does anyone know where I could get charts on the vacuum hoses for a v-10 2003 Georgetown. I loose dash blower sometimes when I accelerate. Ventilation returns when the engine has reached when the accelerator is no longer getting the rv up to speed.

Check this video about the Vacuum canister.
https://youtu.be/0lJfFR59wJI