Gauge wiring help Options

[turtleturtle]

Okay, when I bought my car, these gauge did not work. Upon further inspection, they were never hooked up. So, my question is, how do I hook these up and exactually where?

(IMG:http://www.carsnrides.com/Data//GalleryPhotos//1593-amps%20gauge%20front.jpg)

(IMG:http://www.carsnrides.com/Data//GalleryPhotos//1593-amps%20gauge%20back.jpg)

(IMG:http://www.carsnrides.com/Data//GalleryPhotos//1593-temp%20gauge%20front.jpg)

(IMG:http://www.carsnrides.com/Data//GalleryPhotos//1593-temp%20gauge%20back.jpg)

[TimK]

Hi,

I don't have an ammeter on my '75 914 (the gauge that says +30/-30), but I would guess there's a current shunt somewhere in the system inline with the positive terminal of the battery. The current shunt has a tiny resistance to it so as current gets pulled through it, it generates a voltage. You need to wire this voltage to the two large terminals on the +30/-30 gauge to have it register. Don't worry if you get the wires backwards the first time, the gauge will just operate in the opposite direction.

As far as the temperature gauge goes, there are three terminals at the bottom of the last picture. I'll call them top, left and bottom. The bottom one goes to the +12V supply (Red/white wire). the left one goes to ground (brown) and the top one goes to the temperature sending wire (green/black) from the oil temperature sending unit. My '75 has a black 3-terminal socket connector with these wires already attached to it. You can probably find +12V and ground somewhere there, but do you have a green/black temperature sending wire near the temperature gauge?

Regards,
Tim

[turtleturtle]

Hi,

I don't have an ammeter on my '75 914 (the gauge that says +30/-30), but I would guess there's a current shunt somewhere in the system inline with the positive terminal of the battery. The current shunt has a tiny resistance to it so as current gets pulled through it, it generates a voltage. You need to wire this voltage to the two large terminals on the +30/-30 gauge to have it register. Don't worry if you get the wires backwards the first time, the gauge will just operate in the opposite direction.

As far as the temperature gauge goes, there are three terminals at the bottom of the last picture. I'll call them top, left and bottom. The bottom one goes to the +12V supply (Red/white wire). the left one goes to ground (brown) and the top one goes to the temperature sending wire (green/black) from the oil temperature sending unit. My '75 has a black 3-terminal socket connector with these wires already attached to it. You can probably find +12V and ground somewhere there, but do you have a green/black temperature sending wire near the temperature gauge?

Regards,
Tim

The temp gauge clearing tells you where to hook up which wire, but where does the engine send get connected to? The left is the sender, top is ground, bottom is 12V.

There are no wires for the temp gauge anywhere to be found.

[TimK]

I'm looking at the Haynes manual right now to figure this out. What year is your 914? The early 914s (up to '71) had the temperature sending wire (green/black) tied to terminal 3 of the regulator plate (according to the wiring diagram). It looks like '72 had no temperature gauge. '73 and onward, the oil temperature gauge looks optional. Perhaps someone put gauges in your car from another 914 but the original car didn't have the current shunt or oil temperature sensor installed.

In my '75, the green/black wire for the temperature sending unit comes from a sensor on the right side of the engine compartment. It merges with the factory wiring harness that contains the large red wires attached to the primary 12V battery. Do you have any green/black wires on the right side of the engine compartment? Check both top and bottom sides. I removed the engine for an electric vehicle conversion, so I don't have a picture of where the green/black wire originated from...

The temp gauge clearing tells you where to hook up which wire, but where does the engine send get connected to? The left is the sender, top is ground, bottom is 12V.

There are no wires for the temp gauge anywhere to be found.