a/c not blowing out the main vent

Asked by Jun 21, 2013 at 03:09 PM about the 2000 Mercury Grand Marquis LS

Question type: Maintenance & Repair

a/c works great, just not blowing out of main vent. defrost and floor work fine

4 Answers


Your heater/ac register controls are vacuum actuated. I would start under the hood and locate the vacuum supply coming from the firewall (right side above or near the black plastic heater case) and trace it to a "T". There will be a vacuum line to the intake manifold (supply), and a vacuum line to a vacuum canister or reservoir. There is also a check valve that allows the reservoir to take over in case of a low vacuum signal (like passing or pulling a hill). I work on Crown Victoria Police Interceptors (same car, different badge, more fun). Usually it's a vacuum supply concern - a broken line.

16 of 16 people found this helpful.

Ac not coming from ac vents

15 of 15 people found this helpful.

Don't know


You could try to see if the solenoids are actuating the control the flappers that change the direction of air flow there's a couple of them. They work off of the vacume system.

1 of 1 people found this helpful.

Your Answer

Add photo

Related Questions

Grand Marquis

Looking for a Used Grand Marquis in your area?

CarGurus has 1,835 nationwide Grand Marquis listings starting at $2,000.


Search Mercury Grand Marquis Questions

Mercury Grand Marquis Experts

#1 Tracy Hooks
Tracy Hooks
Reputation 5,540
#2 kbro
Reputation 2,080
#3 Js08016
Reputation 1,800
View All

Related Models For Sale

Used Ford Crown Victoria
16 Great Deals out of 1,221 listings starting at $1,595
Used Lincoln Town Car
34 Great Deals out of 1,791 listings starting at $1,500
Used Chevrolet Impala
589 Great Deals out of 34,066 listings starting at $899
Used Ford F-150
2,068 Great Deals out of 207,301 listings starting at $1,499
Used Ford Taurus
270 Great Deals out of 20,569 listings starting at $1,995
Used Honda Accord
941 Great Deals out of 77,703 listings starting at $899
Used Cadillac DeVille
4 Great Deals out of 1,626 listings starting at $1,988
Used Buick LeSabre
20 Great Deals out of 1,919 listings starting at $1,000
Used Ford Mustang
543 Great Deals out of 45,840 listings starting at $1,999
Used Toyota Camry
1,098 Great Deals out of 90,895 listings starting at $1,599

Used Cars For Sale

2010 Mercury Grand Marquis LS For Sale
88 listings starting at $3,150
2009 Mercury Grand Marquis LS For Sale
6 Great Deals out of 77 listings starting at $3,599
2008 Mercury Grand Marquis LS For Sale
8 Great Deals out of 91 listings starting at $2,250

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.