QuestionQUESTION: I have a 1986 deville V8 w/ only 58000 miles . the warning coolant and temp lights go on when the air con or heater or defrosters are turned on. the lights go off when the regular vent switch is turned off or the off button is pushed. The warning light also goes off when the car reaches a speed of 40 mph or more. The sensor has been changed. any thoughts? thank you for you reply... lee
ANSWER: Check to make sure that there is enough anti-freeze in the radiator and that the plastic overflow jug is at the FULL mark. re-Check the overflow jug after you drive and let the car set for a few hours also.
What EXACT sensor did you change ?. What is the EXACT name of it ?.
Is it the COOLANT SENSOR or the ENGINE METAL TEMP SENSOR ?.
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QUESTION: it was the coolant sensor. our local mechanic replaces it. the plastic jug is always full. that was one of the first thing I checked. the other interesting thing is that when I change to the regular vent button, the light goes off 98 % of the time. When I switch the off button for all the vent, heating, defroster etc. the light goes off. Could this be a wiring problem?
Thank you for your prompt reply to my first query and thank you in advance for this query.
Lee
ANSWER: The ONLY lights that can come ON are:
SERVICE NOW
STOP ENGINE TEMP
SERVICE SOON
BRAKE
SERVICE ELECTRICAL SYSTEM
STOP ENGINE OIL
NO CHARGE
COOLANT TEMP/FAN
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QUESTION: I'm sorry, the answer has no relation to my follow up question. The follow-up is: the coolant light/fan is the ONLY warning light that comes on when the air-con, defroster, or heater buttons are turned on. It goes off when the vent button is turned on or when the car reaches a speed of 40 mph. The coolant sensor has been replaced and the coolant reservoir jug is always full. Could it be a wiring problem?
Thank you in advance, lee
ANSWER: Let's check for CODES in the computer:
1. Ignition ON, Engine OFF.
2. Simultaneously push and hold the OFF and WARMER buttons on the climate control panel for 3 seconds and release them.
3. Codes will display in the form of LETTER and NUMBERS and will stop at .7.0
4. Tell me If you get ANY CODES such as E41 or EE41 or F48 or FF48 or any other letter/number combination . I need to know EXACTLY how they display as if you were video taping them and in the EXACT order in which they display.
5. Turn igntion OFF.
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QUESTION: In Answer: I did as you instructed. The codes were displayed in the following order: ...F; .F41; .F49; .0.7.0
Thank you again... Lee
ANSWER: Was that an F41 or FF41 ?.
F41 or FF41 = A problem with the cooling fans.
F49 or FF49 = Due to the high temperature of the engine because the cooling fans are not working properly the AC compressor is disengaged.
I can provide PICTURES and DIAGNOSTIC test procedures for you to do if you e-mail me at: onlineautohelp@msn.com
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QUESTION: thank you for you reply. In answer to your question, the diagnostic codes were: f41 and f49. Not ff41 or ff49. Both fans behind the radiator are working well. Are these the cooling fans you mentioned? Also the air conditioner works quite well even though the warning light goes on under the previously mentioned conditions. What else could it be?
ANSWER: CLEAR (erase the F41 and F49 codes from the computer and see if they return.
Procedure:
Perform steps 1 thru 3 above and you will see .7.0.
Now simultaneously push and hold the OFF and LO buttons until you see F.0.0 and release the buttons and turn the ignition off.
Wait 2 minutes and perform this test:
1. Ignition ON, Engine OFF.
2. Simultaneously push and hold the OFF and WARMER buttons on the climate control panel for 3 seconds and release them.
3. Codes will display in the form of LETTER and NUMBERS and will stop at .7.0
4. Tell me If you get ANY CODES such as E41 or EE41 or F48 or FF48 or any other letter/number combination . I need to know EXACTLY how they display as if you were video taping them and in the EXACT order in which they display.
5. Turn igntion OFF.
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QUESTION: I did the above tests. After erasing the computer codes I waited two minutes. I performed the last 5 steps again and the code shows: F . . then it flashes off then the F41 code comes on. No other code follows.
hoe you had a nice vacation.
AnswerWhat you have is a faulty:
Wire connection at the fan or fans.
A faulty wire connection at the cooling fan control module or Body Control Module (BCM computer)
Failing fan motor.
Failing fan control module.
A short to ground in one of the wire circuits.
I can provide PICTURES on how to command the blower motors via the climate control panel to determine which component is at fault.
E-mail me at: onlineautohelp@msn.com.
