I am having some electrical problems with my 1990 Honda accord. the high beam head light won't work, also the tail lights stop working and its not the fuse because the clock and front park light work just fine. also it wont rev pass 3500 rpm neither driving nor in park(neutral)
please help

 

Put a multimeter on the battery, turn everything on, see how much the voltage drops from nothing on to everything on. If it drops under 12V at any point in time, or the car has trouble staying running with everything, change out your alternator and battery.

Check your fuses and relays.

Take out the wiring diagram and a continuity tester and check the lines one by one. A fusable link may have gone and if that's the case you'll have to locate it and fix it which, honestly, can be a pain in the butt.

The other thing you can do is check the parts that the voltage hooks up to by pulling the connector and testing the voltage with it on and the car running. More than likely, though, check any box that both the engine and car electronics go through for debris, corrosion, water, etc.

 

thank you much,
I'll try the multimeter, but as for the fuse and relay I checked ever possible one both under the hood and under the dash, they are all good, I do notice that when I flick the switch for the high beam you can hear the relay in the fuse box under the hood clicking but no lights,