2000 mercury grand marquis air conditioner and heat seem to be running at the same time and defroster will not work.

Asked by Oct 16, 2013 at 05:52 PM about the 2000 Mercury Grand Marquis LS

Question type: Maintenance & Repair

the air conditioner on my 2000 mercury grand marquis operates with the heater on also. therefore it doesn't cool very well. also the defroster does nt function.

1 Answer


You have a heater door problem in the dashboard sounds like the AC/Heat door is NOT closing al the way AND the Floor/Defrost Door is not switching either. Sometimes 'things' will fall down the defroster duct and screw up the doors. Disassembly required to clear them. If you are sure there is nothing down there then you may have a broken vacuum line in the engine compartment that feeds the dashboard that is broken. Check against the firewall in the engine compartment on the passenger side - there will be white / red / green plastic lines. There will be one going directly to the dashboard around the heater hose area ( you may also find a hose broken off a mushroom shaped thing at the firewall - It shuts the water going to the heater core) Everything is control by vacuum going to your dashboard control. If you here hissing at the dashboard control - the control its self is bad - Good Luck

Your Answer

Add photo

Related Questions

Search Mercury Grand Marquis Questions

Mercury Grand Marquis Experts

#1 Tracy Hooks
Tracy Hooks
Reputation 5,300
#2 kbro
Reputation 2,050
#3 Js08016
Reputation 1,670
View All

Related Models For Sale

Used Ford Crown Victoria
11 Great Deals out of 963 listings starting at $2,990
Used Lincoln Town Car
27 Great Deals out of 1,817 listings starting at $1,695
Used Chevrolet Impala
556 Great Deals out of 28,522 listings starting at $700
Used Ford Taurus
211 Great Deals out of 19,276 listings starting at $500
Used Ford Mustang
334 Great Deals out of 45,523 listings starting at $2,000
Used Ford F-150
2,390 Great Deals out of 209,711 listings starting at $895
Used Honda Accord
696 Great Deals out of 83,201 listings starting at $500
Used Cadillac DeVille
6 Great Deals out of 1,582 listings starting at $1,499
Used Chevrolet Tahoe
645 Great Deals out of 27,669 listings starting at $600
Used Chevrolet Silverado 1500
1,978 Great Deals out of 160,605 listings starting at $1,850

Used Cars For Sale

2010 Mercury Grand Marquis LS For Sale
7 Great Deals out of 91 listings starting at $4,100
2009 Mercury Grand Marquis LS For Sale
4 Great Deals out of 81 listings starting at $4,300
2008 Mercury Grand Marquis LS For Sale
4 Great Deals out of 93 listings starting at $500