You can't. What's going on is a loss of vacuum to your HVAC controls. It's likely that you have a vacuum check valve, vacuum line or vacuum reservoir that is leaking or that has failed. Just left of center, under the hood and attached to the Firewall is a vacuum canister and a "T". Usually, the problem is the check valve (the "T") but could be a broken vacuum line.
all air flow is coming out from the defrost vents in front windsheild . how do i manually change it to the vent position
2004 Mercury Grand Marquis LS Premium
-
Maintenance & Repair
My '05 Grand Marquis has 140K miles. Recently the front a/c vents quit blowing cold air. For the next 2 weeks we drove it with cold air coming out of the vents on top of the dash only. After 2 week...
2005 Mercury Grand Marquis GS
-
Maintenance & Repair
I just don't know if the seat can be raised or how to do it
1997 Mercury Grand Marquis 4 Dr LS Sedan
-
Maintenance & Repair
what is the physical process to replace the fan blower switch that is located in thge dash board ?
2008 Mercury Grand Marquis LS
-
Maintenance & Repair
How do I remove the old heater hose in a 2000 mercury grand marquis?
2000 Mercury Grand Marquis LS
-
Maintenance & Repair
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. Content will be removed if CarGurus becomes aware that it violates our policies.