Looking for the wiring diagram for the cab of a 1993 D350. Having issues with headlights flashing on and off. Took a meter to them to find out they are losing complete voltage. Also truck is a wiring nightmare fuses bypassed and relays jumped.

 

Have a look here.

 

I just bought a new battery and my lights are going dim when I hit a bump in the road. My gauge reads low voltage. What's going on?

 

Recheck your battery connections. Make sure they are squeaky clean.

Find out why the alternator isn't charging your battery.......

 

Battery connections are good. I even put a meter on the starter while I was recharging the battery. Starter is fine
I don't really know enough about wiring. I'm stumped.

 

What is alternator output with the engine idling? Check output AT the alternator. Yours has an external voltage regulator, doesn't it??