I have a 2000 gmc 6.5 tbd 2500 that makes a clicking/ buzzing sound under the dash when I try to start it. The problem began when I tried to use an electric charger/starter to get it running. Now besides the noises the Clock/radio won't turn on, the glow plugs aren't making the noise that they use to and the lift pump clicks but doesn't run as long as it should. So far I've tried cleaning the terminals and cables, checked fuses, and tried recharging batteries. I had the batteries checked a few months ago and I will do it again asap.
Thanks in advanvce for any help.

 

I cleaned the terminals again and no progress. I have read that the electric charger/starters can damage the electrical system, but I don't know which component is damaged and causing the problems. Does anyone know what would make the clock/radio not turn on with the ignition?