While this is for a 1992 Honda Civic, I've been told it is the same for a 1991 model. http://autoforums.carjunky.com/Automotive_Repair_C1/Electrical_and_Wiring_F6/FUSE_BOX_DIAGRAM_FOR_92_HONDA_CIVIC_P3020/
Yeah, it will fit. But the 1991 civic sohc 1.5 transmission is cable and the 1992-1995 transmission is hydraulic. So yeah it will fit no it will not work with out doing other work. Also The speed sensor is cable in the 1991 and the 1992-1995 is electronic,.....so more work.
The fifth generation of the Honda Civic was introduced in 1991 and the production was stopped in 2000. That's why one needs to look for a 1992 Honda Civic on the used car market. The car can either be bought online on websites like eBay or from a local used cars dealer.