Two things that come to mind are possibly low on Freon or a bad compressor. Maybe someone else has more ideas.
the radiotor or the cams
A 1995 model would have an R-134a system.
The 1995 ford Aerostar did not come stock with a factory amp. If your van has an amp then it was added aftermarket.
What is the firing order for 1995 Ford Aerostar 30L and direction of rotation on distributor?"
Yes
My 1995 Ford Explorer has a diagram in the front of the engine compartment showing how the serpentine belt is routed . Does your Ford Aerostar not have that .
A ( 1996 ) Ford Aerostar has a ( 21.0 U.S. gallon / 79.5 litre gas tank )
On a 1995 Ford Aerostar : If it is the 4.0L EFI V6 engine ( like my 1995 Ford EXPLORER ) it has an " O " ring for the thermostat , there is no gasket But , if it is the 3.0L V6 engine I believe a thermostat gasket is used
On a 1995 Ford Aerostar 4.0 and 3.0 V6 engines : 3 - 6 2 - 5 1 - 4 front of vehicle
On the 1995 ford Aerostar, the speed sensor is located on top of the differential. It is a magnetic style, mounted close to the input shaft.
On my 1995 Ford Explorer , to lower the underbody spare tire , I open the liftgate and the access hole is located above the rear bumper at the center of the bumper ( I assume your Ford Aerostar would be similar )
Crankshaft Sensor Location 1995 aerostar 3.0 l videos