I have a 1999 honda accord ex that won't start. I have door and overhead dome lights but nothing else. The chime when the key is in the ignition works but the power locks don't work with the switch on the inside.

Install a new battery.

On the 1999 Accord Ex that won't start and has no power besides the dome and side door lights, the clock and the security lights on the radio and drivers door lock, I replaced the battery and the same problem exist. I looked at a wiring diagram and it has a multiplex unit on the drivers and passenger side and I guest one in the driver door. Could one of them be the problem?

. Test all under hood and under dash fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post252145

By carefully checking all fuses, it may solve some of the outstanding electrical issues.

. For the crank but won't start situation, perform the tests in the link below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-11.html#post2123675

I found a 50amp fuse in the fuse box under the hood that had a screw backed out causing a bad contact point.

Good job.