260E with #9 fuze that keeps blowing
 

I had a problem with the dome light, radio, hazard lights, dash clock not working. I checked the fuze box found the number 9 blown. I replaced it and it blow again. So I unplugged the dome light and everything worked fine. I figured I just needed a new dome light assembly. I replaced it and the samething started to happen again. After doing some seaching in this forum I think I my have a bad power seat diode. My question is which one is it? I think I know wear it maybe located. But I just want to be sure before I start pulling things out.
Another problem I'm having in the my alarm no longer makes a sound if it goes off. The lights flash but the horn does not work. Any thoughts on this?
Thanks