all electrical goes dead on start

[sharkdog]

Hi All,
been working on getting my truck back on the road seems to be running good but sometimes when I go to start it and turn the key I here a click and the whole truck goes dead. then I have to remove both battery terminals and reattach to get the electrical to work again and attempt another start. would this be the solenoid(that's where the click seems to come from)?

Thanks, again