2nd Gen S-series (1995-2005) Tech Discuss 2nd generation s-series (1995-2005) general tech topics here.

hissing from behind hvac controls

Old 01-20-2013, 09:35 PM
Beginning Member
Thread Starter
Join Date: Sep 2012
Posts: 11
fireman32_14 is on a distinguished road
Default hissing from behind hvac controls

my 97 just recently started hissing from behind the hvac control ****, the selecter that changes where the air comes out, it hisses until you get the engine under load then eventually goes away, i assume its a vacuum leak behind there, am i going to have to replace the whole control unit or could it be a vacuum line? also it still seems to work, just hisses, especially on the floor mode
Old 01-21-2013, 11:18 AM
Junior Member
Join Date: Mar 2012
Location: Illinois
Posts: 293
aa21830 is on a distinguished road

The hissing will probably eventually get worse until you start to lose control of where the air comes out the vents. At minimum, pull off the control panel and see what you find. Unplug the connector where all the multi-colored vacuum lines plug into and see if there is any fluid or moisture in or around the holes. Those lines typically do not break down and leak, but if they get t-case fluid in them (read all about it here), they won't seal well at the connections, and you'll get some hissing.
Related Topics
Thread Starter
Last Post
2nd Gen S-series (1995-2005) Tech
06-26-2018 07:09 AM
General Chat
02-14-2013 04:48 PM
2nd Gen S-series (1995-2005) Tech
06-11-2012 08:13 PM
1st Gen S-series (1983-1994) Tech
01-14-2009 10:24 AM
1st Gen S-series (1983-1994) Tech
11-14-2007 01:01 PM

Thread Tools
Search this Thread
Quick Reply: hissing from behind hvac controls

Featured Sponsors
Vendor Directory

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.