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I'm installing new repro harnesses in my 1964 GTO. I have aftermarket mechanical Sunpro Oil pressure and temp gauges already installed so original sending units are gone. I'd like to keep the Sunpro gauges but also have the dash lights functioning. How can I make this work? Are there sending units that support both? Another way to configure and retain the original harness wiring?
 

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I kept the ‘64 oil dash lite when I added
An SW mechanical oil gauge by adding it to
a ‘T ‘(below) at the Oil filter oil port, your Sunpro sender prob is sitting There now, you’ll need to get the original dash lite sender from Ames or elsewhere if you don’t have it and add it to the T when u install it..
The water port was tight at front of manifold, and just too difficult to add
A properly functioning T , so I gave that one up and just left the mechanical There,
you would again need to get the original sender For the water lite put on a water T ,
It’s difficult to get proper Water circulation in a T thou for both the water gauges to work well.
Figured by the time the dash water lite
Came on it’s too late anyways, but maybe you may have enuf room to put a T on the water port , depends on which manifold you have on the ‘64.or look around ,you might find a separate water port avail on one of the heads .you need a separate wire
For both senders from both locations
Like PJ once said , Be wary of adding excess tape or sealant to the sender threads as the electricalType Senders need a good block ground to work properly..
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I use aftermarket speed hut gauges, they have analog gauge and high and low idiot lights built into the gauges that you set yourself with a button....you can easily change the warning lights for any parameters high or low.

they use one sender per gauge......not original and not in dash...just another way to go
 

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I'm installing new repro harnesses in my 1964 GTO. I have aftermarket mechanical Sunpro Oil pressure and temp gauges already installed so original sending units are gone. I'd like to keep the Sunpro gauges but also have the dash lights functioning. How can I make this work? Are there sending units that support both? Another way to configure and retain the original harness wiring?
No, there aren't sending units to support both. The ones for lights are simple on/off switches that react to temperature or pressure that "flip" at a specific set point. The ones for gauges are actually variable resistors that change resistance in proportion to what they're measuring (pressure, temperature, etc.).

It's possible to have both functioning warning lights and functioning gauges, but they have to be wired as two separate systems, each with it's own appropriate sending units. You'll either need to use tee fittings like the ones Jetzster posted to install both sending units and switches, or take readings from multiple locations. For instance, use the oil filter housing location for the oil light warning switch and install the oil pressure sending unit where the oil gallery pipe plug is on the top rear of the block, near the distributor.

Bear
 

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Discussion Starter #6
Yepper.

I have OE warning lights and aftermarket gauges. Temp and oil.
LATECH, Can you share what type of 'T' you used for the temp? Thanks.
I'm trying to keep all stock options functioning. So having temp light also functioning would be nice. I'm relying on the mechanical aftermarket gauges for monitoring for any performance issues.
 

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My intake has 2 ports for coolant temp sensors. I used the factory light on one side and put the capillary tube in the other for a mechanical gauge
 

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My intake has 2 ports for coolant temp sensors. I used the factory light on one side and put the capillary tube in the other for a mechanical gauge
Thanks LATECH, here is a pic of my intake. Looks like I have another port more to the center. Wondering if I can use this for the idiot light sensor?
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That is a for engine vacuum. You can put a vacuum gauge on it, but it doesnt have coolant behind it.

There should be a plug for coolant on the side of the cylinder heads IIRC.That would be a good place for the electrical sensor.

My intake has 2 ports.It is an aftermarket one .
 
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