It is on the back of the Power Steering pump. The power steering pump is located on the left hand side of the engine. It will be a cap with the dipstick molded on to it. Remove the cap and you will be able to see the fluid.
At the front of the engine , towards the drivers side of the engine ( power steering fluid reservoir on a 1998 Mercury Grand Marquis )
Into the power steering reservoir.
It is part of the power steering pump assembly.
I was looking at a picture in the 2003 Mercury Grand Marquis Owner Guide and it shows the power steering fluid reservoir at the front of the engine compartment between the engine coolant reservoir and the engine air filter box
Directly behind the steering wheel.
On a 2008 Grand Marquis, the power steering reservoir is located on the driver's side of the engine compartment, near the front. It is typically mounted on the engine, close to the power steering pump. The reservoir is usually a small, translucent container with a cap labeled "Power Steering." You can check the fluid level through the side of the reservoir.
The thread on cap on the engine coolant reservoir is the " radiator cap " on a 1995 Mercury Grand Marquis
On a 1997 Mercury Grand Marquis : The thread on cap on the engine coolant reservoir is the 16 PSI pressure cap / radiator cap
the fuse box on a 1991 ford grand marquis is located right under the steering wheel
According to the 2001 Mercury Grand Marquis owners manual the fuse panel is below and to the left of the steering wheel , by the brake pedal , and has a cover on it
fuse box under steering wheel
Mercury Grand Marquis was created in 1983.