as far as i know it on the vac by the firewall left side
(NO) that sez you can add a valve on the pump side.
On the Ford A4LD automatic transmission the modulator valve is on the passenger side of the transmission ( it might be behind a heat shield )
on the passenger side of the transmission about 2/3 thirds of the way back it will have a vaccume line hooked to it !
Bank 1 is the passenger side of your engine in a 1996 Ford Aerostar
On a 1997 Ford Aerostar : The fuse box is under the instrument panel , on the drivers side
it should be written down the side of the " dip stick" where you look when you check to see if the fluid is low!
I have a 5.8L in my 1990 and it is located behind the intake on the passenger side. Right by the valve cover.
It probably doesn't have one. If you don't see it stuck on the driver's side of the throttle body, that one came EGR valve-less.
On a 1997 Ford Aerostar : The fuse box is under the drivers side of the dash
On a 1993 Ford Aerostar : The automatic transmission modulator is on the passenger side of the transmission ( it might be behind a heat shield )
The rear heat coil is operated by a solenoid valve located in the rear side compartment. You have to remove the middle seat and access the compartment by removing the cover where the blower is located. The valve is controlled electrically by the front or rear controls. There are two possible problems: there is no power going to the valve, or the valve itself is bad. Check the voltage going to the valve first with a meter. If you have power going to the valve then the valve needs to be replaced.
it is located on the driver side valve cover in the back may be easier to get to from the inside