climate control/tachometer

[Asj61]

I have a 2005 special edition, my wife tried the a/c this week and noticed hot air blowing from the vents, by searching this forum I was able to complete the climate control self diagnosis to determine code 2798 which indicates "driver coolant control valve short to ground". The test is performed with ignition in "on" position but engine not running. I say all of that to say this, with the ignition in the "on" but not running position the climate control unit seems to work normally, but when I start the engine the tachometer works normally as well as the climate control unit then within 15 seconds the tach goes to zero and climate control goes dark. As if someone pulled the fuses. I have repeated the process several times with the same result. Any suggestions?

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[Asj61]

Links for the climate control self diagnosis:
http://www.**************************/problems-thunderbirds-climate-control-system/

 

[NC Flattop]

I have a 2005 special edition, my wife tried the a/c this week and noticed hot air blowing from the vents, by searching this forum I was able to complete the climate control self diagnosis to determine code 2798 which indicates "driver coolant control valve short to ground". The test is performed with ignition in "on" position but engine not running. I say all of that to say this, with the ignition in the "on" but not running position the climate control unit seems to work normally, but when I start the engine the tachometer works normally as well as the climate control unit then within 15 seconds the tach goes to zero and climate control goes dark. As if someone pulled the fuses. I have repeated the process several times with the same result. Any suggestions?

Check Fuse1, 10A, Fusebox under the hood. Owners manual says it is for a/c compressor, but it must also supply power for other parts of the system. Error codes went away after replacing the fuse. I had the same problem with constant hot air from vents. I replaced coolant control valve, but it did not correct the problem. Fuse1 did fix the problem.

 

[Bird of Prey]

Thanks for the suggestion. I had the same problem. I checked for a blown fuse. It was blown. I replaced and the Heater/AC works perfectly again.