Vacuum line help

[xeqshnr]

I was pokin around under the hood of my Yukon today and noticed a small vacuum line that wasnt connected to anything. It comes out of what appears to be some kind of inline valve on the heater hoses. I had a buddy check his 98 pickup and it doesnt have the valve on there. He also said he had never seen one setup like mine. Heres a pic of the valve, any help would be greatly appreciated.

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[JenneK]

Yeah, that thing will open and shut the flow of coolant to the heater core depending on the temp called for in the cabin. It's controlled via vacuum pulse.

Damn...I just bypassed by heater core and I can't recall where it connects... sorry.

 

[xeqshnr]

Thats kind of what I figured. ButbI.cudnt find where to hook it up. I found a place for another vacuum hose but it looks like its for one of those small hard lines. Heres a pic of it. That piece is different on the 98 pickups also.

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[retorq]

On my 95 that vacuum connected to an electrical connector on the AC evaporator bracket. Should be the same or close on yours ...

 

[gpracer1]

Goes to a vac solenoid between the engine and receiver dryer, mounted to the firewall.

 

[xeqshnr]

Thanks guys I will check it out

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[BattelWagun]

Thats kind of what I figured. ButbI.cudnt find where to hook it up. I found a place for another vacuum hose but it looks like its for one of those small hard lines. Heres a pic of it. That piece is different on the 98 pickups also.

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I believe this is part of your EVAP system...

 

[xeqshnr]

Thats what my buddy called it. I couldnt remember what he had said.

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[BattelWagun]

Thats what my buddy called it. I couldnt remember what he had said.

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Yep, that actually vents fumes from the gas tank back into the manifold to cut down on unused emissions. They've been known to be very finicky, so I wouldn't play with it. Very costly to replace too...

 

[xeqshnr]

Goes to a vac solenoid between the engine and receiver dryer, mounted to the firewall.

Found it thanks!

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