'78 Fuel Pump Relay gone bad?

[Premo34]

Year/Model: 1978 280z

I recently changed the original fuel pump to a compatible Airtex model. Before the work was done i had power to the fuel pump. After the install i went to start the car and I'm getting no power to the pump. I've chased wire from the pump, up behind the passenger seat, all the way to the fusible link and the battery. I'm thinking the issue MIGHT be the fuel pump relay. Is there any way that it could have been damaged in the process of changing the fuel pump?

The first thing i did was disconnect the fuel pump relay and crank the engine to eliminate fuel in the lines. I then disconnected the negative terminal of the battery before any work was performed. I know it isn't the wiring of the pump itself. i multimetered the connection behind the passenger seat and no power there. I've looked at the wiring diagram until my eyes crossed. 

The fuel pump harness that plugs into the fuel pump relay has 4 wires: 2 green, 1 black, 1 white with black stripe. When the harness is plugged into the relay, i have power to one green wire, but not the other green wire which I think should be the hot output wire from the relay (both green wires should be hot when key is in "on" position) 

Can i be certain that the relay is bad because i'm not getting power to both green wires. Also...the key is in the "on" position while im doing my readings. (on a 1978 triggers the pump on)

Before i go and buy an expensive fuel pump relay ($70-$100) i wanted to bounce the situation off all of you knowledgeable Zheads.

Thanks in advance for responses its much appreciated!

[SteveJ]

Okay, the harness at the fuel pump relay has 4 wires: white/black, black, green/blue and green/blue.

If the white/black wire never has 12VDC+, you don't have the voltage to energize the coil.

If the black wire does not have continuity with the negative post of the battery, you have a grounding issue.

If you see voltage on the white/black wire, you have continuity between the black wire and negative post, and you jumper the green/blue wires together to get a running pump, you have a relay issue.

Of course, with no oil pressure and the alternator still, you will not see voltage on the white/black wire.

[Premo34]

Thank you for the response. Exactly what i needed to know