I just recently bought a 94 civic DX coupe and all of the electrical stuff was working when I bought it, however now after driving it for a couple weeks the taillights will sometimes work and sometimes they wont. Same thing with the speedometer, sometimes the speedometer will come on after 60mph and work normally. I tried changing the fuses and taking the aftermarket radio out as that was a suggestion on another forum, and neither of those solved my issue. The previous owner went to town on the electrical wiring and I have no idea what I am looking at or even where to start. Any help is greatly appreciated!

 

Two separate issues. Troubleshoot separately using a multimeter,.