Express & G-Series Vans Offered in both a full size van, or a large box truck, the Express is the modern GM workhorse

Chevrolet Express
Platform: GMT Van

Vacuum operation of control

Thread Tools
 
Search this Thread
 
Old March 11th, 2018, 1:51 PM
  #1  
Newly Registered
Thread Starter
 
MR WIZARD's Avatar
 
Join Date: Mar 2018
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Default Vacuum operation of control

My g30 only has a defrost outlet working..no center vents..any helpful time saving tips before removing the dash? Thanks
Old March 11th, 2018, 2:09 PM
  #2  
Super Moderator
 
mountainmanjoe's Avatar
 
Join Date: Feb 2017
Posts: 5,783
Received 612 Likes on 553 Posts
Default

Haha Mr Wizard. Like the name.
Probably a rotted out vacuum line. Have a gander under the hood.
Old March 11th, 2018, 3:51 PM
  #3  
CF Veteran
 
StanVan's Avatar
 
Join Date: Jul 2008
Location: Harrisonburg Virginia
Posts: 1,306
Likes: 0
Received 13 Likes on 13 Posts
Default

When HVAC in a car looses vacuum, it will revert to defrost.
Old March 15th, 2018, 10:08 AM
  #4  
CF Junior Member
 
jimmyblue's Avatar
 
Join Date: Jun 2014
Posts: 35
Likes: 0
Received 0 Likes on 0 Posts
Default

On my '02 1500 Express I found the soft line from the "T"
to the reservoir ball had fallen off due to the end splitting.
This is accessible from the hood, right next to the battery.

Dunno how or whether newer / older are much different -
G30, what year & motor?

At that same "T" you could check motor vacuum and if
none, check the other end of the "hard" (plastic) line to
the manifold vacuum port; if attached there and no far
end vacuum, suspect plastic line cracking and replace
with a full run of rubber vac hose.




All times are GMT -5. The time now is 3:09 AM.