Fuel Pump wiring

[87MJTIM]

I was looking under my 87 for something unrelated to what I found today.  I saw wire on the fuel pump (FP) not connected to anything.  The harness has 3 wires: orange and purple connecting to the pump, and a naked black wire (see picture).

 

 

The 87 wiring diagram shows just 2 wires at the FP: 1 orange and 1 black.

 

The connector diagram shows the C305 as having one wire and the C306 have a flat, blade connector.

 

What is the purple wire?

Where does the black wire connect?  There is no other connector visible, screw to attach a flat connector.

[87MJTIM]

Additionally, the fuel gauge works fine.

[eaglescout526]

Did the flat blade soldered to the sending unit rust off and away?

[derf]

Purple wire is likely the sending unit wire.  They're together in the tank.

[JZLAJeep]

1 minute ago, 87MJTIM said:

Additionally, the fuel gauge works fine.

As I learned on the farm, "we don't fix things that work."

[87MJTIM]

That is very sound advice. 
 

I just want to make sure the black wire isn’t what’s holding everything together. 

[Ωhm]

Wouldn't the black wire enter the tank using that grommet used by the other two wires?  If so, then pump and gauge are finding ground thru the metal tank & straps.

[87MJTIM]

Winner winner chicken dinner 

 

I have a MTS fuel pump. Three wires at the connector. 
 

Looks like I need to change the FP. 

[Ωhm]

[GonzoTheGreat]

Stock, the black wire has a female spade terminal, and there is a male spade terminal soldered/braised onto the sending unit flange for ground, like @eaglescout526said.

 

Orange is pump +

Purple is gauge sender

 

I also had the black wire break on my '89, and somehow the pump grounded through the tank and straps, and it still worked 

[87MJTIM]

4 hours ago, GonzoTheGreat said:

Stock, the black wire has a female spade terminal, and there is a male spade terminal soldered/braised onto the sending unit flange for ground, like @eaglescout526said.

 

Orange is pump +

Purple is gauge sender

 

I also had the black wire break on my '89, and somehow the pump grounded through the tank and straps, and it still worked 

Good to know it still worked through the tank/straps.

 

The wiring diagram does not show the purple wire.  That was puzzling me.

[Ωhm]

Check Instrument Cluster (fuel sender).

[87MJTIM]

Fuel gauge has worked fine.

[Ωhm]

Check Instrument Cluster (fuel sender) page in the Electrical Manual.