What diagrams are you looking for?
There are some wiring diagrams in  Haynes Manual #1341 for the 1985-91
Maxima models.
-Power Antenna
-Audio system
-Rear window defogger
-Front wiper/washer system
-Headlight system
-SMJ Harness terminal connections
-Fuse and relay location detail
-Computers, control units, and components locations detail
Chilton manual may have more
Factory Service Manual will likely have the most complete set of
wiring diagrams.
Good luck.
Bob
95 SE Auto
89 SE Auto traded