Have no air coming out my vents

1990 CADILLAC FLEETWOOD BROUGHAM
196,000 MILES • 0.5L • V8 • 2WD
Avatar
DEACON ERVIN
  • MEMBER
  • 3 POSTS
Okay, when I turn on heat or air you feel it coming from under the dash but nothing comes out vents, also on defrost it is very light even on high! What's my problem?
Nov 21, 2019 at 6:46 PM
Advertisement
Avatar
SCGRANTURISMO
  • ✓Experienced Mechanic
  • 4,897 POSTS
Hello,

This could be a problem with your vehicle's lower mode valve of the programmer for the Heating Ventilation and Air Conditioning [HVAC] Unit. In the diagrams down below I have included the diagnostic flowchart from the vehicle manufacturer for tracking down mode door problems with your vehicle. There is also a description of how your vehicle's HVAC system operates at the end for your reference. Please go through this guide and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros
Images (Click to enlarge)
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Nov 21, 2019 at 7:45 PM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.