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How do you fix the AC-heater vacuum control so it does not just blow out the defrost on a Dodge Diesel truck?


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2015-07-15 21:24:12
2015-07-15 21:24:12

First U have 2 make sure U have Vaccume @ the belt driven Vac.Pump,then U have 2 repair the Vac.Leak. Some Dodge truck have Vac.lines near the battery & Bat.Acid will make the Vac. line Brake.Some of the Vac.Hoses are in a plastic loom that keeps the hoses & wires 2gether.Loss Of Vac.2 the control is the problem.

I have a 2001 - my problem solution was the vacuum hose that is located right under the weatherstriping for the hood. Just about the center of the block, there is a rubber elbow that faces down and bends to the rear of the truck. The is a small vacuum line that is in a plastic wire loom that should be connected to this elbow. My hose fell out of the elbow and was against the firewall. I re-connected this hose and put a small zip-tie on it(to avoid the problem in the furture) and it now works perfectly! P.S. The 4 wheel drive will not engage the front tires with this hose off either. I found this out the hard way as I got my truck stuck on a slimmy boat ramp trying to pull out my boat!

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you have a vacuum leak. defrost is the default when a vacuum leak is present.

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Because a diesel engine does not create vacuum and the vacuum pump is necessary to operate things like the vacuum assist brakes and cruise control.

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Vacuum pump the same vacuum pump that works automatic locking hubs on the 4wd

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You have a leak in the vacuum supply to the ac control.

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More than likely the vacuum feed line from the engine has been disconnected or cracked. When there is no vacuum supplied to the HVAC it reverts back to the defualt position, the defroster.


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