Gauge Wiring Help

[truckster]

I'm putting an EZ Wiring harness in my 72 Blazer, and while I'm at it I want to convert the ammeter to a voltmeter and convert the oil pressure from mechanical to electrical.

I have both gauges out of an 84 Chevy truck. I also have a new oil pressure sending unit for the same truck. I need to know which terminals to connect on the gauges.

The wiring harness has a wire marked "voltage gauge", so I believe one side of the gauge is grounded and the other is connected to the corresponding wire.

I believe the oil pressure gauge is grounded through the oil pressure sending unit, so one side should be +12v and the other connected to the oil pressure wire.

If anyone knows which terminal is which, I would really appreciate the help. Also, each gauge has a third terminal. Is that a ground, and does it need to be connected?

Thanks in advance.

[kwmech]

Doesn't it usually say on the ceramic piece?

[ray_mcavoy]

On the voltmeter, the terminal that's off to the left (as shown in your photo) is the one that's connected to the voltage you want to measure. The terminal that's up toward the top/center is ground. And the terminal over on the right is an intermediate connection between the ceramic resistor and the internal meter coil (don't make any external connections to that post).

On the oil pressure gauge, the terminal that's off to the left is the one that gets connected to the sending unit on the engine. The terminal that's down toward the bottom/center is ground. And the terminal over on the right is +12V.

[67 Burb]

Hey, Truckster, after you get it all back together, take a photo from the front. I'd like to see what the conversion looks like.
Thanks.

[truckster]

Originally Posted by kwmech

Doesn't it usually say on the ceramic piece?

There weren't any markings that I could see. My eyes are kind of old, but my reading glasses didn't reveal anything.

Originally Posted by ray_mcavoy

On the voltmeter, the terminal that's off to the left (as shown in your photo) is the one that's connected to the voltage you want to measure. The terminal that's up toward the top/center is ground. And the terminal over on the right is an intermediate connection between the ceramic resistor and the internal meter coil (don't make any external connections to that post).


On the oil pressure gauge, the terminal that's off to the left is the one that gets connected to the sending unit on the engine. The terminal that's down toward the bottom/center is ground. And the terminal over on the right is +12V.

Thanks. That helps me tremendously.

Originally Posted by 67 Burb

Hey, Truckster, after you get it all back together, take a photo from the front. I'd like to see what the conversion looks like.
Thanks.

Will do. I'm trying to take pictures to document everything I've been doing. I'll post up what I end up doing.

[truckster]

Here's the finished product:

http://www.67-72chevytrucks.com/vboa...58#post8855858