There isn't an alternator relay. There is a Voltage regulator, but it is inside the Alternator and should have been checked when it was looked at.
There are two 50 A fuses, F2 and F6.
Make sure the Ground wire to the engine block is good.
The alt leads to the PCM at pins 57 and 20 directly. through some other things on other pins. 57 looks like it is a power wire for the PCM and 20 looks like it is the wire that would sense what the alt is doing.
Do you know it isn't charging because of reading it with a meter or using the meter on the dash? Did you check the fuses under the dash or just the ones in the engine compartment? The Dash meter reads through the inder dash fuse box, it also shares a line with the speedo, tach, Brake warning light, powers all the guages, but not their lights and also powers most of the dash idiot lights.