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*FIX* Running HVAC controls without vacuum canister

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*FIX* Running HVAC controls without vacuum canister

Old 10-01-2018, 07:17 PM
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*FIX* Running HVAC controls without vacuum canister

*Mods feel free to move*

*For N/A models only, you need a vac canister for turbo models due to boost being introduced to the system that runs on vacuum*

So this is my 2nd post, but given I've been having difficulty finding a clear solution, I'm hoping/feeling this may help shed some light on the daunting HVAC / Defrost / Heat problem.

I was blessed with a car that had the vac canister ripped out and no regards to what went where as far as engine bay lines, so I ran a line from the plenum --> 1-way check valve --> T-fitting --> (1 line to top of water **** solenoid, other to inside firewall to T-fitting supplying all under-dash vac sources). Made a short 3min video explaining and showing this as well for those of you who are visual like I am.

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Old 10-03-2018, 01:43 AM
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Great video, but needs several corrections. For those who has vacuum canisters, but has a HVAC system stuck on defrost, DO NOT assume that the vacuum canister is the problem. It is possible that it is a SYMPTOM, NOT the CAUSE. I have a similar issue on my car, stuck on defrost. I initially assumed that it was the vacuum canister's fault because the vacuum system seems to work (ish) if I bypass it, but that's the "Hack" way to fix the issue. The real issue is that I have a leak in the vacuum system due to cracked hoses. The vacuum canister limits the air flow for the vacuum line going to the HVAC controls for some reason, but it would be fine on a properly working HVAC system with no leaks. If you bypass the vacuum canister, you might have a working HVAC system again, but you aren't fixing the problem. The only way to actually fix the issue is to fix the leak in the first place.

Another part, unless you live somewhere where it's always hot outside, do not connect the water **** diaphragm (little thing that goes inline with the heater core hoses) directly to the intake manifold. Doing so will close off the water **** and disables the heater core in the car. It's fine to leave it disconnected since there's a blend door that directs air towards or away from the heater core, depending on the temperature setting set in the car.
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Old 10-03-2018, 08:38 AM
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Great addition. Yes sorry I should have specified this "fix" is for if you've narrowed down the source of the issue to be the vac canister.

Also I did not know that with the water ****. I live in Texas, sooo...ha thanks bud.
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