I have a 1993 buick regal custom with 3.8 V6 fault codes

if you are having to refill reservoir, you have a leak. check fittings where hoses were disconnected. Personally I would have replace all the hoses.

Clean throttle body,fuel filter,air filter.

run fault codes to find the reason for the engine light coming on

The fans are controlled by the ECM and it uses the ECT sensor for temperature sensing, so if the check engine light isn't on the sensor is not the problem. You need to have an active test run on the fan system to see what code is returned. Have you tried powering up the fans at the relay?

you would need a new a/c pump, however you you didnt want to replace it and could live with out the a/c, a cheaper option is to replace the belt and bypass the a/c. Most auto parts store will sell you a belt of the correct dimensions if you tell them you wish to bypass the a/c. I've done this for many customers. It can be done on just about any motor.

Best of Luck.....

That fault indicates a problem in the electronic cooling fan circuit. More specificly the output driver in the onboard computer has detected a problem with the control circuit of the electronic fans. First inspect for correct operation of both radiator mounted fans.

Firing Order:
1-2-3-4-5-6
Cylinders:
1--3--5
2--4--6
(front of veh)
Distributor Connections:
1-4 6-3 2-5
Let me know if this helped, or if you have additional information or questions. Feel Free to contact me at FixYa.com!

your problem is a result of weak/poor idler tensioner operation due to a weak spring in the idler tenisioner and need to be replaced

Check to see if you have a lot of dirt in the throttle body. Clean the throttle blades out with brake cleaner or throttle body cleaner. You'll see alot of dirt come out. Keep spraying until it comes out fairly clear and wipe the throttle body out with a rag. If this doesn't do it, you may have a problem with the throttle position sensor (TPS). This sensor controls the idle after the car warms up and keeps it from dying when you brake or sit at idle.