how do i fix the ac? on 1998 Cadillac Seville STS

The ac and heater work at the same time in my car how do i fix it?

Asked by for the 1998 Cadillac Seville STS
Air conditioning systems are temperamental to work on and I suppose in the auto repair industry have the highest repair dissatisfaction rate and come backs. The system has to evacuated, the refrigerant stored or replaced after repair, the system should be flushed, properly checked for leaks and then repaired and retested, it depends what other problems are found and how diligent the person is repairing the system. Costs and estimates as you have probably found out vary widely. Special gauges are needed to measure pressure or evacuate and recharge the system. Controller operation ect requires test instructions which can be complex. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate
1 more answer , 2 more comments
Sounds like your controller has failed. Have it checked at a qualified shop.
Hi Pat. How's it going?