You should download the TMs for the truck from the 'Resources' tab at the top of the page. The TM number for the CUCV is 9-2320-289-##. The -20 is the intermediate maintenance manual and includes all of the wiring diagrams.
I have a butchered harness from one of my trucks, I'll see if those relay sockets are still there so you can splice them back in. A better bet might be to find someone parting out a CUCV and remove the entire dash harness and replace it if there are lots of parts missing. It's not that hard since the wiring is so simple on these trucks, I've done it twice myself to solve hacked plugs.
ETA- The dash wiring harness is the same for all trucks EXCEPT for the 1010 ambulance. The truck harness and Blazer harness are interchangeable.
The Gen 2 relay has 4 wires: Pink/Black, Black, Brown, Brown/Red
The Voltmeter relay has 4 wires: Pink/Black, Black, Black, White
The two Black wires in this are because the switch controls the ground of the voltmeter so both sides of the relay are grounded. The Pink/Black wires are the 12V trigger wires, hot when the ignition is on and are on the coil side of the relay. One black wire goes on the other terminal for the coil side of the relay. The other two wires go on the contact side of the relay.
If you want to get the truck working without the socket, you can crimp spade terminals to the wires, and then slide them on the terminals for the relay. They are numbered as follows (look on the bottom of the relay)
30, 85, 86, 87. There may be an 87a but not on all relays. 87a is a Normally Closed contact that opens when the relay is powered up.
http://www.bcae1.com/relays.htm
For the Gen 2, hook the wires to the following terminals.
Pink/Black - 85
Black - 86
Brown - 30
Brown/Red - 87
For the Voltmeter, hook the wires up as follows:
Pink/Black - 85
Black - 86
Black - 30
White - 87
Later,
Joe