AC Gurus Get In Here.......Please

[Marauderjack]

My AC works fine when it wants to.......

When I first start the car on a warm day it historically would got to MAX automatically and start cooling immediately!!:beer:

The last few days it starts blowing like it's on MAX but doesn't start cooling immediately......may take 2-5 minutes then it kicks in and works perfectly the rest of the day but let it sit overnight and it gets "LAZY" again??:cool:

Called my Ford Service and Parts guy and he said he would ask his AC guy but never called back??

It works GREAT after it wakes up.......Ideas......a sensor somewhere maybe??:confused:

[fastblackmerc]

My AC works fine when it wants to.......

When I first start the car on a warm day it historically would got to MAX automatically and start cooling immediately!!:beer:

The last few days it starts blowing like it's on MAX but doesn't start cooling immediately......may take 2-5 minutes then it kicks in and works perfectly the rest of the day but let it sit overnight and it gets "LAZY" again??:cool:

Called my Ford Service and Parts guy and he said he would ask his AC guy but never called back??

It works GREAT after it wakes up.......Ideas......a sensor somewhere maybe??:confused:

I assume the compressor is turning before it starts cooling.

Maybe the blend door sticking.

[Marauderjack]

No Jim......the blend door is fine.....AC blows out the dash and heat to the floor but the compressor does not run until it decides to now??

Thinking maybe the sensor in the air plenum may not be working right?

What sensors signal the compressor to startup??

BTW, I ran the EATC diagnostics again and it did the same thing......searched for 15-20 seconds then the display lit up like a Christmas tree.....see photo!!

[jimlam56]

Is this the first A/C problem you've had Jack?
I know you have a few 100k miles on your MM!
On my 03 300a (now Sonny boys) the compressor imploded and sent bits throughout the system. Happened in SC on the way to Greenville with me in a business suit late for an appointment and the temp outside around 98...

[fastblackmerc]

No Jim......the blend door is fine.....AC blows out the dash and heat to the floor but the compressor does not run until it decides to now??

Thinking maybe the sensor in the air plenum may not be working right?

What sensors signal the compressor to startup??

BTW, I ran the EATC diagnostics again and it did the same thing......searched for 15-20 seconds then the display lit up like a Christmas tree.....see photo!!

The only sensor I know is to the right of the EATC. It monitors the air inside the car to regulate the automatic temperature.

Going look it up in the shop manual.

[Marauderjack]

Yep...it has worked fine for almost 9 years and 243,xxx miles......guess I'm lucky but I still wanna fix it!!!;)

Checked the charge last year....A-OK!!:beer:

[Marauderjack]

The only sensor I know is to the right of the EATC. It monitors the air inside the car to regulate the automatic temperature.

Going look it up in the shop manual.

There is also one under the hood in the chamber that holds the evaporator Jim....at least there is a plug there!!:cool:

[babbage]

What about the AC compressor clutch? You can re-shim it if clutch does not engage - then you'll get cold air.

[Marauderjack]

What about the AC compressor clutch? You can re-shim it if clutch does not engage - then you'll get cold air.

I've done that twice so far and the current gap it less than .005" probably around .003"........should be OK??:cool:

Thanks for your input!!:beer:

[fastblackmerc]

There is also one under the hood in the chamber that holds the evaporator Jim....at least there is a plug there!!:cool:

That is probably the Ambient Temperature Sensor. Is it hex shaped with a 2 round pin connector?

The In-Vehicle Temperature Sensor has 2 flat / spade type pins.

You need an OHM meter to check them both.

[Marauderjack]

Any particular value for them Jim??

[fastblackmerc]

Any particular value for them Jim??

The Ambient Temperature Sensor is located at the front center of the car. This gives you outside air temperature also.

Ambient Temperature Sensor:
@ 50-68 degrees F - 37,000-58,000 ohms
@ 68-86 degrees F - 24,000-37,000 ohms
@ 86-104 degrees F - 16,000-24,000 ohms

In-Vehicle Temperature Sensor:
@ 50-68 degrees F - 37,000-58,000 ohms
@ 68-86 degrees F - 24,000-37,000 ohms
@ 86-104 degrees F - 16,000-24,000 ohms

[Marauderjack]

Same values for both....I'll check 'em and get back to ya!!

Thanks!!:beer:

[Marauderjack]

GOT IT FIXED........WOOT....WOOT!! :party:

It dawned on me yesterday that there are several relays under the hood in the BIG fuse box!! I looked in my owner's manual and VOILA.....relays #201, #202, #203, and #204 run the Horn, PCM, Fuel Pump....and THE AC CLUTCH.......WOOT!!:bandit:

I switched the Horn #201 and the AC Clutch #204 and started the car........INSTANT AC clutch engagement with NO HORN......what a LUCKY discovery!!!:eek:

Off to CarQuest today......I will probably replace all FOUR of them for peace of mind!!;)

This little relay musta clicked in and out a BILLION times over 9 years and 244K miles......it has a right to be tired!!:D