it does appear to be a complete system. it looks like a "deluxe" heater with 4 levers. pic 1 is not part of the system, it looks like a windshield washer pump or something. pic 2, 3 shows the control valve that has been added, not part of the original. it should be inside the big black box. they tend to stop working and are not made aftermarket, maybe thats why it was added outside the box. for electrical there should be a brown wire running from the fuse block to the blower switch then from the blower switch to the resistor, pic 4, 6 then an orange wire out to the blower itself. there is a gray wire from the fuse block to the lamp in the 4 lever housing too. if the motor doesn't work, first check the fan by hooking 12v to it. these fans are available aftermarket. the blower resistor looks bad and needs to be replaced. it's not overly complicated it either the fan or more likely the resistor that is the problem. here a link for info on heaters. good luck....
http://67-72chevytrucks.com/vboard/s...d.php?t=488618