Connecting Oil Pressure Sending Unit to VDO GNX Style Gage Cluster

[gn87man]

First off, I am a total rookie at wiring....

I currently have a GNX style gage cluster in the car. Before I had my old engine removed, the oil pressure readout at the gage was working fine.

The guy who removed my engine misplaced the oil pressure sending unit. I am assuming he also removed the oil pressure wire that runs through the firewall to the back of my cluster because I do not see a wire running through the firewall that would be used for the oil pressure sending unit. All wires running through the firewall have been accounted for.

So now I have to purchase a new oil pressure sending unit and wire it to the back of the oil pressure gage on my VDO GNX style cluster.

What the is part # and where do I purchase a compatible VDO Oil Pressure Sending Unit for my VDO GNX style gage cluster?

Once I receive the oil pressure sending unit, how do I wire the VDO Oil Pressure Sending Unit to the back of my VDO GNX style gage cluster?
Anyone have pictures of this installation?

I have attached pictures of the front and back of my VDO GNX gage cluster. One of the pictures is the back of the oil pressure gage.

Thank you so much in advance for any help.

 

[Turbo6inKY]

The original "sending unit" is a just a switch that toggled the idiot light in the dash. It also served as a backup method to energize the fuel pump relay to enable the car to limp home in case of ECM failure. The wire for it runs through the engine harness and comes in with that mess behind the glove box. You should check the harness behind the alternator and see if they just cut the wires. If they did, you can splice an extension back in and not have to run a new wire all the way back.

As for the sender, you need to check with VDO for the part number of a sender that's compatible with the gauge and fits in the port on the block.

 

[gn87man]

Great information! Thank you sir! I will contact VDO today to determine the correct sender for my VDO Vision gauge. I will also check the harness behind the alternator to see if the old sender was spliced to a wire in that area. Thank you again!

The original "sending unit" is a just a switch that toggled the idiot light in the dash. It also served as a backup method to energize the fuel pump relay to enable the car to limp home in case of ECM failure. The wire for it runs through the engine harness and comes in with that mess behind the glove box. You should check the harness behind the alternator and see if they just cut the wires. If they did, you can splice an extension back in and not have to run a new wire all the way back.

As for the sender, you need to check with VDO for the part number of a sender that's compatible with the gauge and fits in the port on the block.

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[nwarky]

I can't respond to the knowledge shared by Turbo6inKY but looking at the picture of the wiring in the back of the oil pressure gauge I believe the gray and black wires go to the bulb, the red wires to power the gauge, (can't see this clearly but there should be ground wires to the connector next to the red wire connector) and the purple wire is to the sending unit. Keep following the purple wire back to the engine compartment which should connect to the sending unit. Hoping this helps a little.

 

[gn87man]

I can't respond to the knowledge shared by Turbo6inKY but looking at the picture of the wiring in the back of the oil pressure gauge I believe the gray and black wires go to the bulb, the red wires to power the gauge, (can't see this clearly but there should be ground wires to the connector next to the red wire connector) and the purple wire is to the sending unit. Keep following the purple wire back to the engine compartment which should connect to the sending unit. Hoping this helps a little.

Thank you so much! I will follow the purple wire back through the firewall to see where it goes. I am currently installing a new oil pressure sending unit because the engine builder only installed a plug in the hole in the block which was for the oil pressure sending unit. I appreciate your help.

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[GNRick]

You should install a T for the factory sender and for the vdo sender. Check at your favorite hardware store. The factory wire will power your fuel pump if the fuel pump relay on the passenger fender fails. Plus the bright red idiot light alerts you to low oil pressure.

 

[gn87man]

Thank you very much! I found a brass T fitting at the hardware store. I don't think the car had the factory sender on it when I bought it. It just had the vdo gauge. Here is what mine looks like....

You should install a T for the factory sender and for the vdo sender. Check at your favorite hardware store. The factory wire will power your fuel pump if the fuel pump relay on the passenger fender fails. Plus the bright red idiot light alerts you to low oil pressure.

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[GNRick]

Yep. You are missing the factory sender. The factory connector is probably around there somewhere.

 

[gn87man]

Gotcha....yeah I will keep looking for it. Thank you again for your help.