a friends crazy stereo installation

My friend was tring to install a new stereo into his '93 Jeep Wrangler. Well he got happy at first and just took the old one out and started to just cut random wires. He bought a random wiring harness and failed in an attempt to make it work. So giving up he proceeded to hook back up his old stereo. Well, he must have gotten some wires crossed becasue it only worked (got power) if the head lights were on. A few weeks later he attempted to do it again but failed again. I did talk him into going to autozone to buy a tests to determine whice wires supply the power. After determining that he hooked up ramdom wire and still it wouldnt work. So he decided to go without a radio untill he could have a pro look at it. He later that night discovered that the backlighting on the dash lights were all dead. Probubly a result of hooking up ramdom wires. Anyways I am tring to help him avoid the cost of having a pro install what should seem like a not so difficult job turned quite complicated. Any advice would be appriciated greatly.

Advice:

If you don't know what you are doing DON'T DO ANYTHING.

most wiring loom adaptors "should" come with wiring instructions, just match the right wires up with the ones on the head unit. (the head unit should have come with a wiring diagram somewhere in its instructions.)

Go to a search engine and search for the '93 wrangler wiring harness. I had to do this to do an install in my cherokee. I found a page through Google.com that had all the Jeep wiring diagrams, I however did not save this link. Also, my jeep has an amp under one of the seats, if you have an amp it might be easier to get the remote turn on lead from here, this is in fact what I ended up doing.