i have a 98 civic dx. when i got the car the radio harness connector was cut. it did have a radio in it, so i know the wires arent cut anywhere else. now i bought a 99 civic radio and the connector for it.
i followed this diagram, i did search

http://www.installdr.com/Harnesses/HA-Wiring.pdf

im getting power through the harness and the ground is working. however the radio wont turn on, when i put the radio in my friends 99 civic it works perfectly. any ideas? i checked the fuses, they are fine.

shouldn't the radio atleast turn on with just power and ground? im not much of a audio guy so im not sure. i know i should of taken it to someone who is, but i was bored. figured id give it a try

 

There two power source. 1 is the constant 12v+ hot for memory/backup pin O and the second is 12v+ acc pin P when you turn the key. the acc fuse is under the dash fuse the the memory/backup fuse is located under the hood.