Stuck on defrost

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Jan 30, 2012 | 08:15 AM

waterboy_fishing

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From: Adrian, Mi

Stuck on defrost

Got in my truck this morning and my air control would not switch from defrost to floor or any other position. What should I check for first? It is a 6.0 Diesel if that makes a difference. Sill trying to warm my toes up after the ride.

Jan 30, 2012 | 08:27 AM

thomabb

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When you first turn your key on you should hear the vacuum pump run to build vacuum in the system. If it runs constantly you have a vacuum leak. If it never comes on you need to hunt down why.

Jan 30, 2012 | 11:45 AM

SDElwood

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From: Savannah, GA

Yep, thomabb has got it exactly right. You either have a vacuum leak or lack of it. Cool thing is, if the little electric pump is bad, they are only like $80 at Napa. BK 6002973. But it's rarely the pump.

Jan 30, 2012 | 11:48 AM

biz4two

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From: Albuquerque

Here is a GREAT video to help you out. It's done by a FTE member...

<iframe width="560" height="315" src="http://www.youtube.com/embed/MoI-BbisYEs" frameborder="0" allowfullscreen></iframe>

biz

Jan 30, 2012 | 12:18 PM

waterboy_fishing

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From: Adrian, Mi

Quote:

Originally Posted by thomabb

When you first turn your key on you should hear the vacuum pump run to build vacuum in the system. If it runs constantly you have a vacuum leak. If it never comes on you need to hunt down why.

Come to think of it I don't recall hearing the usual motor noise low rumbling, and thump I usually hear when it switches. The only thing I recall hearing was the fuel pump building pressure.

Jan 30, 2012 | 03:21 PM

thomabb

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"Roger, that's you bogey."

Jan 31, 2012 | 12:38 PM

waterboy_fishing

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From: Adrian, Mi

My pump is running all the time. Would it be all right to unplug it temporarily until I get a chance to find the leak? I don't want the pump to burn up.