Electric fan blues

[ARTTY]

Howdy,'yall. Question, would it be a good idea to wire my car's electric cooling fan into a manualy operated toggle switch on the dash? would it do something bad to the fan switch, like bypass it, or keep it from sending signals to the "main brain" concerning engine temps which govern air/fuel ratios? Someone told me that this would be the consequenses of doing such a modification. Another person said he did this trick to his PT cruiser and nothing went wrong. I also read a reply to another member's question about fans that to test the fan, turn on the key, then switch on the A/C and the fan should come on. I tried that, but the fan still doesn't come on. when I unplug the switch the fan comes on, but throws the power loss light and the idle goes way up. Also, with the switch unplugged, the engine is VERY hard to start. Please advise before I do something stupid. Thanks, ARTTY.