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Discussion Starter #1
So i know the A/C vacuum leak has been covered and ive been doing a bit of searching for the answer to my question, but unfortunately i havent found the answer yet so here goes,

I recently did the splice job for the white vacuum line leak under the hood. cut the loom back, slid some new line on, and heat shrinked the whole thing to keep it all together. Unfortunately, after doing all that work, my A/C and Heat still blow out of the defroster. My next step is to replace the whole line but before i do that id like to further understand a little more of what the hell im doing.

with the vacuum valve under the dashboard, if i manually move that it blows out the vents, and not the defrost. However if i manually move the one under the hood i dont notice a difference.

My questions are, with the one under the hood, if the rod is pushed into the vacuum valve, what exactly is supposed to happen for that?

im assuming that the whole system is all conected so a leak somewhere in it would prevent the under the dash valve from opening/closing like it was supposed to.

if there was no other leak, could a busted vacuum valve under the hood cause this issue?


Like i said my next step would be to replace the whole line from under the hood through the firewall. if theres anythign else im missing please fill me in.

 

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The one in the picture only operates on max ac

When you switch it to max ac the actuator closes
 

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Discussion Starter #3
Ok thanks, so it looks like i still have a leak then, and maybe i need to replace the one in the picture
 

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That white plastic vacuum line is supplied vacuum from the engine via a black vacuum line that runs to a small vacuum reservoir before heading to the dash.

The HVAC defaults to the Defrost position with no vacuum applied.


Start at the vacuum supply then work your way to the dash.
 

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i wouldnt be surprised with a cut under dash vacuum line.
 

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the lines under the dash are usually fine. The actuator under the hood is for the fresh air vs recirculating cab air. Here are some under dash pics so you can see whats goin on under there.

This switch can get brittle and crack and cause a vacuum leak.....


one of the valves under the dash.


It takes the blue line


General layout of the air box.


 

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Discussion Starter #8
I FOUND IT.

Lol I'm so kicking my ass right now. Turns out that while I was doing the splice job on the white tube, I totally missed the fact that the black one right next it it out side of the loom going towards the engine was totally cut in half from when we lifted the motor to do the oil pan gasket and timing cover replacement.

IFeel like an idiot now.
 

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Good Learning experience.

Sometimes, it's not always the obvious answer.
 
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