I went outside to start my 87 7.3 today and when i turn the key on to heat the glow plugs the wait to start light didnt come on and everything started clicking on and off really fast. My pyro gauge was going up and down and the starter would only make this really fast clicking noise and wouldnt actually spin. At first i thought it was the gp relay but its almost everything on the truck that is going on and off.

 

start with inspecting the battery terminals followed by a boost/charger if need be.sounds like the batteries went dead on ya.did you check to see if you left the lights on or anything like that?

 

exactly what i was thinking

 

The batteries arent dead

 

Cool!

 

My money is on dead batteries. I would say there is a good chance the external voltage regulator took a dump and shorted out, in which case if your batteries aren't totally yet they will be soon.