Jump to content

Forums/Z31P/z31-repairs-forums electronics/*FIX* Running HVAC controls WITHOUT vacuum canister

From Z31 Library
Revision as of 05:16, 15 May 2026 by z31p_Ubernathan (talk | contribs) (Forum archive import (z31performance))
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Imported from Z31Performance.com Forums{{#if:Ubernathan| — original post by Ubernathan}}{{#if:2018-10-02 12:45:46|, posted 2018-10-02 12:45:46}}{{#if:3| · 3 post{{#ifeq:3|1||s}}}}{{#if:/Z31performance_archive/forum/z31-repairs-forums/electronics/541258-fix-running-hvac-controls-without-vacuum-canister.html|
Local archive: view archived thread on dev.z31library.com}}

Ubernathan: (2018-10-02 12:45:46)

  • 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 had 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 cock 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. Hope this helps some out there with the same problem.


Dunkine: (2018-10-03 00:16:20)

Nice Vid

Turbos have a check valve on them already.

A few have done something similar with the Vac canister to keep it from going to defrost when accelerating hard.

Have you tested it under load yet?


Ubernathan: (2018-10-03 02:55:13)

{{#if:Dunkine|Dunkine wrote:|Quote:}}

Nice Vid

Turbos have a check valve on them already.

A few have done something similar with the Vac canister to keep it from going to defrost when accelerating hard.

Have you tested it under load yet?

Thanks, just trying to help someone out there. Under load it functions just as it should, so I was really happy about that. I need to charge my AC but I could feel the different between air when the solenoid would open and close under heat/cold.