Newbie heater issue

[Norexpy]

Hello!
First post coming up... Have searched the web and in the forum posts but can't find an answer. Have recently bought a 2003 EB 5,4. Love it! Has worked great, but suddenly the heater wont work properly. Have digital instruments, and until now I could just choose the desired temp and the car would do the rest. But now it just blows cold air - until I max it out (32 degrees celsius). Then the heater responds and blows hot, hot, hot. Have read about common faults that require the entire dash to come off - but all of them state that car does not blow hot air at all. Could it be the termostat?
Greatful for all kinds of help. Great forum!

 

[stamp11127]

Don't have experience with the second generation but this is for the first gens and may still apply:

The EATC system is inoperative, intermittent or incorrect operation:

Circuitry short/open.
Input sensor(s)/erratic input signals.
Charging system.
Automatic temperature control sensor hose and elbow.

Electronic Automatic Temperature Control Module Self-Test:

The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A NGS tester must be used to retrieve these concerns.
The EATC module self-test will detect concerns in the system control functions and will display hard diagnostic trouble codes (DTCs) in addition to intermittent diagnostic trouble codes for concerns that occur during system operation. The vehicle interior temperature should be between 4-32°C (40-90°F) when performing the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed.
The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated.
To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed.
If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given.
If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Improper Operation.
To exit self-test and retain all intermittent DTCs, push the blue (cooler temperature) button. The control will exit self-test, retain all intermittent DTCs and then turn OFF (display blank).
To exit self-test and clear all DTCs, press the DEFROST button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC control assembly will turn OFF (display blank) and all DTCs will be cleared.
Always exit the self-test before powering the system down (system turned OFF).
Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.

If it works please post the DTC"s

 

[Norexpy]

Thanks

I will try this.
But has anyone experienced the same thing? Would be nice if it turned out to be a quick fix.

 

[krakoosh]

I don't know if this system is the same as mine, not an EB, but the blend doors on my 03 XLT in front are run off vacuum and the rear are electrical. Look under the battery tray for a broken or cracked hose.

 

[Hamfisted]

Hello!
First post coming up... Have searched the web and in the forum posts but can't find an answer. Have recently bought a 2003 EB 5,4. Love it! Has worked great, but suddenly the heater wont work properly. Have digital instruments, and until now I could just choose the desired temp and the car would do the rest. But now it just blows cold air - until I max it out (32 degrees celsius). Then the heater responds and blows hot, hot, hot. Have read about common faults that require the entire dash to come off - but all of them state that car does not blow hot air at all. Could it be the termostat?
Greatful for all kinds of help. Great forum!

Test the hot water valve for vacuum leaks and free movement. Get a hand pump vacuum gauge Mityvac Automotive Tune-up and Brake Bleeding Kit - Tools - Mechanics & Auto Tools - Automotive Specialty Tools from Sears or any autoparts store to test the valve. It should hold vacuum when you put it to it. Then with the dash temp selector set to warm you should feel vacuum at the small vacuum line that was connected to the valve as well. But if the valve diaphragm has a leak in it, it will act like you are describing.


-Mike



Here's the hot water valve under the hood....

 

[Norexpy]

Thanks guys

Vacuum leak sounds logical. Hope you are right. Will test and get back to you. Worth mentioning that everything seemed to work just fine today. Had not done anything but warm air filled the car when I tried to set 22 degrees celsius. Strange. Thanks for the picture.