2000 Grand Marquis Hissing Dash

[Ryan]

Gah, go look under the dash on drivers side, look for loose vacuum hose. Automatic parking release maybe?

[2000marquis]

Gah, go look under the dash on drivers side, look for loose vacuum hose. Automatic parking release maybe?

it is not that that is only or mostly on the older grand marquis and crown vics

[Ryan]

It happened on my 95 vic.

[2000marquis]

It happened on my 95 vic.

what color is the parking brake release vacuum hose???

[2000marquis]

now when i put the parking brake on and put it into drive from park it releases the parking brake so i really do not think that is the problem

[97grmarq]

that is what i am leaning towards now what would i have to do to fix that problem buy a new climate control box??

now i had another used one at the house and i took the one out of my car and put the other used one in and it still does it

but there is like 4 hoses behind the climate control box and there is one port open thaty does not even have a hose is there suppost to be a hose there?? now when i disconnected the box i heard the sucking noise like vacuum

what should i do b/c this is really!!!!!!!!!!!!!!!!!!!!!!!!!!!!!111 annoying

thnaks alot

vacuum motor is there on the climate control?? or it located some where else in the car??

just happened to take my control out too.missing 1 hose too in the back.guess it's supposed to be that way.the control box is probably not the problem.

[86VickyLX]

now when i put the parking brake on and put it into drive from park it releases the parking brake so i really do not think that is the problem

It'll still do it's job, but it will hiss sometimes.

[2000marquis]

well now my problem is there is like 3 vacuum cans under the dash and i need to find out witch one to replace can someone tell me a easy way to find out witch one it is b/c these babys are $52 a piece at the dealer ship

[86GmLsCoupe]

You can use teamfordparts.com for diagrams, Motorcraft's online catalog and Rockauto.com. An Alldata/DIY subscription never hurts, doesn't cost much, and you get TSB's. I use all of the above mentioned for finding out which parts I need and to cross reference numbers. You should also really look in getting part number, and typing it into amazon or goggle shopping, you can often get really good deals. I just purchased a new Motorcraft blower motor, thermostat, and air charge tempo sensor for around $75 altogether.

[TomO]

I don't know if this will help, but on my '89 GM, there was a loud hissing sound coming from under the dash. The hissing sound seemed to vary in intensity depending on how I moved the transmission shift lever. For example, when it was in drive, if you moved it around a little bit, the hissing would change in loudness. I eventually found that the hissing was coming from the valve that controls the automatic parking brake release.

On my car, it's some sort of rotary valve that is mounted, if I remember correctly, to the steering column behind the lower dash. It is connected to the transmission shift shaft that runs down parallel to the steering column. Moving the shift lever moves part of the valve. When the transmission shift lever is moved out of park, this valve diverts vacuum to a vacuum actuator that is connected to the parking brake release lever.

I cannot recall now exactly how the lines ran. Basically what I did was disconnect the vacuum line running from the main vacuum manifold to this parking brake release system, then I plugged the nipple on the manifold where the hose(s) was/were hooked.

That cleared up the hissing sound right away. No more hissing at all, but the automatic parking brake release will not function, of course. It doesn't bother me one bit because I'm used to manually releasing the parking brake anyhow.

Note that simply disconnecting the vacuum actuator canister on the parking brake release and plugging the line will not help if the valve is the source of the hissing, because the valve is upstream of the actuator. So, even if you disconnect the actuator, the valve is still getting vacuum, so it will still leak and make a hissing sound. You need to disconnect the valve and plug that line. Like I say, this is the way I remember things, but it's been a while and my memory is a bit faded now.

I don't know if this will help or not, but I thought I'd throw it out -- maybe it will help somebody with the same problem.

[TomO]

Ok here is my problem

when i press the gas i do not hear the hissing noise
but when i let off the gas i hear the hissing noise

Don't know if this needs mentioning, but I believe the reason for this is because when you open the throttle by pressing the gas, the engine vacuum falls. Conversely, when throttling back or at idle, the vacuum is high.

[Lincolnmania]

leaking vacuum motor for the climate control is probably what is leaking......i have replaced a few on the 98-02 cars

did you check the vacuum motor? if it dont hiss with the heat on then it's the one for the blend door leaking