Both cooling fans come on as soon as I turn the ignition off and they keep running until the battery runs dead. Its not overheated and the relay switch seems to be good. Any ideas what cause them to run and a solution to fix?
Sounds like your fan relay(s) are stuck in the 'on' position or there is defective fan switch(s), a shorted A/C pressure switch and/or even defective/shorted fan motor diode for the A/C system.
The point is that this system has several components that can fail and cause the fans to run when they should not. I would begin by testing the above components using the electrical diagram.
here is a to a link to a place where you can get the diagram.:
http://bit.ly/mitchell_repair_manuals_online
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