my car is getting to 220 degrees and staying there nowadays (stop and go traffic, 100 degree weather) after installing a 180 degree thermostat, and i would like to install a manual fan turn on switch. im sure im not the first one to ask, but what and how would you go about doing this? are there any drawbacks to doing such a thing?

87 z28 305 4 barrel

 

Install a switch to ground the dark green wire on the fan relay.