What triggers the electric aux fan in the engine bay to come on?
 

ever since I replaced my turbo the aux fan will come on with the ignition and runs constantly. disconnecting it from the AC system does disable the fan. ideas on troubleshooting?

a short to ground on the A/C pressure switch or a short to ground on the coolant temp thermoswitch

hmmm... I did replace the original coolant temp sensor in the lower rad hose w/ the turbo...
 

I'll start there... thanks for the heads up!

good luck!