electrical wires

[gene knight]

i have 2 black wires with open spade connectors that are on the back of my 1970 datsun 521 by tail lights / license plate frame. 1 wire is on the right side of frame near the right tail light/side marker light, that is factory taped up in harness, the other wire is by the spare tire mounting running along the x member. but according to my wiring diagram in repair manual it does show those wires. i need any info about these 2 wires,cuz the license plate light is 1 red wire and is grounded by the bracket/plate to the bed of truck

[DanielC]

Do you mean open eye connectors?  Are they made of brass?  They ground the rear of the bed wiring harness to the frame of the truck.

A lot of 521 trucks benefit from having an added ground wires from the tail light metal frame to the frame of the truck also.

[gene knight]

DanielC: i didn't have these wires on my other 521, but they are open eye connectors. i added wire from tail light frames to spot on frame. so should i connect the wires in question to frame

[DanielC]

I think the wires were added when the 521 got the side marker lights.  The rubber base of the side marker light insulated it from the body sheet metal, so the ground wires from the light needed a connection back to a ground.