What is wrong in my 1999 Toyota Tacoma if my engine is overheating when my AC is turned on. I have replaced the thermostat and it has made it better but it still heats up and ideas?

While changing your spark plugs one did not back out and was very hard to turn to begin with just got this truck 93 t100 and was wondering if there is any way around replacing the head? Where is thermostat located on 1998 Acura TL? Where is the transmission dipstick located on a 1997 Geo Prizm on a 5 speed manual transmission? Where is the EGR valve in a 2003 Kia Spectra? What size wiper blades for 2014 Honda Civic? How do you engage 4 wheel drive on 1996 Toyota T100? What is the TPS on a Mazda Miata? Where is the fuel filter located on 1999 Honda CR-V? Where is the charcoal canister on a 2000 Rx 300? Where is the location of a infinity j30 fuel temperature sensor? Why can't you get your 1992 accord that ran out of gas to start? What would cause all the dash warning lights to come on and stay on on 1992 ES300? How can you tell if it is the right or left wheel bearing bad? How do you unloosen crankshaft bolt on 2001 gs300 Lexus? How do you change the valve cover gasket on a 1998 Rav4? What does 1.6 engine size means? Where is the timing cover on a Honda rancher? Info on gold crest model number XL-7 exposure meter? Where do you add the brake fluid on a 2001 Honda CR-V? Why wont my Mazda 626 rev past 3000 rpm?

What is wrong in my 1999 Toyota Tacoma if my engine is overheating when my AC is turned on. I have replaced the thermostat and it has made it better but it still heats up and ideas?