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?

If your 1999 Toyota Tacoma is still overheating when the AC is on, it could be due to a few issues. One possibility is that the cooling system is not functioning efficiently, which may include a failing radiator, clogged coolant passages, or a malfunctioning water pump. Another potential cause could be insufficient coolant levels or a leak in the system. Additionally, the increased load from the AC could be straining an already weak cooling system, so it’s important to check these components thoroughly.