Fuel sending unit connections

rgp

Low Mileage
Hello folks -

I continue to make progress on my new to me ‘ ‘87 Bertone, although at a slow pace lately due to a bum shoulder. I replaced the fuel tank sending unit as the original one was inoperable. The replacement arrived in a timely manner, but it took me a while to get around to the install. In the interim, I’ve forgotten which of the two wires connects to which connector on the sending unit.
There is a red wire with black stripe and a blue wire with yellow stripe. Connectors on the s bring unit are at the 5 and 9 o’clock positions standing at the rear of the car looking forward at the top of the sending unit installed on the top of the tank. Which wire goes on which connector? Thanks!!
 
This is what my 74 looks like:

Gas Tank Connections - Close Up without Cover.jpg
 
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78 connections, which match Don's 74. Your FI sender won't have the fuel tubes coming out the top, but the connections are most likely the same. If the gauge doesn't work with the wires in this orientation, there is only one other to try.
1300_gas_tank_wires.JPG
 
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It operates on a ground (negative) circuit; as the level drops the resistance to ground changes. So there are actually three wires - but one is just the ground to the chassis. One of the other two wires is for the level in the tank (to the gauge), and the other is to the warning "low fuel" light. So getting them reversed won't damage anything, the gauge just won't work. Therefore as Jim said, you have a 50/50 change, if one way doesn't work then swap them.
 
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It operates on a ground (negative) circuit; as the level drops the resistance to ground changes. So there are actually three wires - but one is just the ground to the chassis. One of the other two wires is for the level in the tank (to the gauge), and the other is to the warning "low fuel" light. So getting them reversed won't damage anything, the gauge just won't work. Therefore as Jim said, you have a 50/50 change, if one way doesn't work then swap them.
 
Thanks all - I left the ground wire out of my post for simplicity. Exactly what I needed to know - I won’t screw up my new sending unit and if it doesn’t work, reverse!!
 
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