I have a service light that keeps coming on and off.

As far as the jumping and service light goes I need you to take it to a auto parts store and have them scan it for codes. Write the codes down and let me know the exact code numbers you have. You probably have a bad pressure control solenoid in the valve body pretty common on those cars. As far as the ac goes do you have auto climate control or manual ac?The most common reason for the ac to be inop on those is the r134 leaks out from a leak somewhere.I have also seen some bad acd clutches bad compressors open terminals to the ac clutch. Does the ac clutch engage when toruning the ac on?

That wrench light still sets P codes when it goes off so there basic scanners can read those its still setting a powertrain code. It will be like a P1811 code I just need to know what codes its setting. They sell basic code readers that will even read those codes. As far as the auto climate control goes if you have it your ac control will display the temp on it. Does your do that?

AS far as the ac goes you will need to check the high and low ac pressures and see if the ac compressor comes on when you turn the ac on.