Last post on Jul 30, 2012 at 2:02 PM
You are in the Ford Crown Victoria/Mercury Grand Marquis
What is this discussion about?
Ford Crown Victoria, Mercury Grand Marquis, Sedan
#4 of 11 2007 Grand Marquis AC through Defroster
Jul 22, 2010 (8:53 am)
Yesterday 7/21/10 replaced the AC/Heater dash controller for $800 parts and labor with 59000 miles. With all the problems Ford has had with this device over the years, they could not engineer a unit that does not crap out unitl 150000 - 200000 miles? 2 car family - 1 American 1 Nissan going to 2 foreign when the Merc dies.
#5 of 11 Re: 1999 grand marquis LS A/C issues [gina26]
Jul 26, 2010 (12:36 pm)
replace belt tensioner
#6 of 11 Not the control head
Jul 26, 2010 (12:39 pm)
It is not likely the control head that is the root cause. It is likely the vacuum harness attached to the back of the control head is loose and needs tie straps to keep it tight to the control head so you don't get a vacuum leak. Vacuum leaks result in system diverting to defrost mode by law.
#7 of 11 2000 MGM Wiper Blade Problem
Dec 12, 2010 (2:41 pm)
My 2000 MGM has a problem where the wiper arms will lift away from the windshield the faster I go leaving water on the windshield. As I slow down the wipers will make contact cleaning the water away from the windshield. I replaced the arms, but it still does the same thing.
#8 of 11 Re: 2000 MGM Wiper Blade Problem [drtripower]
Dec 13, 2010 (11:05 am)
Try attaching a 4 oz lead fishing weight to the middle of each arm. Duct tape may work or tie the lead weight with fishing line. This is not recommended as a fix, but to determine if or how badly you need new arms that are stronger such as found on the Lincoln Town Car.
#9 of 11 Re: 2007 Grand Marquis AC through Defroster [conroejg]
Apr 04, 2011 (7:04 pm)
I did this thing called a cold boot on mine with the same problem. It worked. You turn off the ignition , unplug the two wiring harnesses on the module for one minute then plug them back in and turn on the ignition, press any button but the off and wait for it to reinitialize and calibrate about 30 minutes. It will not appear that anything is happening but start the car and try it now. I found it on a repair database at the library.
Apr 08, 2011 (10:40 am)
i have been working on ac on 99 gm and w/ vaccum lines off i let the vaccum pulled go and now i have hooked all back up and nothing no fan ,defrost, floor, etc... help
#11 of 11 Re: Not the control head [snorkelbobby]
Jul 30, 2012 (2:02 pm)
you had a fix for a grand marquis air blown out the defrost when the ac unit is running. IT was dated jul 26,2010, do you still have the picture for this fix? If you do could email me a copy of the repaired vacuum harness job. I posted your fix below. my email is toneyjordan98yahoo.com
71 of 172 How to fix this problem for $2 by snorkelbobby
Jul 26, 2010 (12:07 pm)
I just finished fixing a 2003 Grand Marquis for air blowing out the defrost only. This is the goverment mandated failure mode.
The problem is that the vacuum harness is leaking vacuum where it connects to the back of the conrol head. The vacuum harness connection ports relax after several years. You can replace the vacuum harness (F5VY-19C827-A) $20, or just clamp it tight with 2 ten inch tie straps from the Lowes or Home Depot.
Pull the trim covering the control head straight out. remove the control head (4 screws). Remove 2 torx screws holding the bottom part of control head in place. Feed a tie strap around this part so it clamps the vacuum harness to the control head. I put one tie strap on either side of the black vacuum supply hose in the center of the harness. Operate the controls to be sure it is fixed.
If you wish, you can disconnect the vacuum harness under the dash for easier working room. It just pulls out.
I can post a picture if needed.