I think the 33316 is a SPST (single-pole, single throw), normally-open relay.
Are the terminals marked? Usually, Lucas relays have the "W" terminals for the coil and "C" terminals for the 'closure'...
To close the relay, you apply +12v at one end (like thru a switch) and ground the other end of the W terminals. Then connect the device to be switched across the C connections.
e.g., for a horn relay, put +12 fused on W1 and connect the horn button between W2 and Ground.
Then, attach +12v (also thru a fuse) to C1 and run C2 to the horn "+" terminal, with the case of the horn grounded by the mounting.
(hope this is clear
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