Aboutautohelp Expertise On hands professional expertise in all aspects of Cadillac diagnostics and repair mid 1970`s thru 2000 year vehicles. GM certified in electronic fuel injection, Automatic transmission, Heating and A/C, and onboard vehicle computer diagnostics.
Experience Held over 15 GM certifications prior to retirement in 1989.
Organizations Prior to retirement held several ASE certifications, numerous Factory certifications.
Expert: autohelp Date: 7/7/2008 Subject: coolant fan temp light illuminates
Question QUESTION: I have a 1986 Cadillac deVille, 4.1L engine with 67563 miles. The air conditioner compressor failed. The compressor was replaced and the system flushed. After 2 months, the "Check A/C" light illuminated. It was determined that several connections were not tightened fully. The connections were tightened and the system was recharged. Now whenever the air conditioner or defrost is turned on, the "Coolant Fan Temp" light illuminates. The fans are both working well and the radiator was blown with shop air to clear the fins of any obstruction and/or dirt. And, the cooling system is filled to the correct fill amount. Is it possibly a sensor going bad or could there be a more serious problem lurking under the cover.
ANSWER: With the engine running at normal operating temp IS or HAS the CHECK ENGINE or any other lights besides the coolant/temp light illuminated.?.
Do you know how to check for computer codes ?. If you do, Tell me what they are.
---------- FOLLOW-UP ----------
QUESTION: With the engine running at normal operating temp, NO other light have illuminated other than the "Coolant Fan Temp" light. I do not know how to check via the dash, but I have access to a Snap On Solus Pro Scanner at my job. I'll scan the car and see what, if any, codes appear.
ANSWER: OK, Let me know.
---------- FOLLOW-UP ----------
QUESTION: I scanned the car and got two codes actually--though not present at the same time. I got a 52, computer reset code, although I mentioned in the previous post that I didn't know how to access the codes via the dash. So I don't know how that was present. The next code was F41, cooling fan problem (according to the Solus Pro scanner). And to reiterate, the light only comes on whenever "Auto" is pressed--auto air conditioner or auto defrost. If I use "Economy" air or defrost, the light will not come on. I have also verified that the fans are in deed working when the Auto button is pressed and the light comes on.
Answer F41 is a cooling fans problem. You will need, If necessary, Electrical schematics, Test procedures and picture locations of the components within the system that is causing you problems of which can't be done on this website which only allows one picture. I do not have a website so you will have to e-mail: onlineautohelp@msn.com in order to obtain the information.
