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I reversed it just to see what happens, I would not reccomend it. It seems to shorten the life span of the IR to about 3 seconds.......hahahaha. I don't know if reversing it really did it in or not, but it no longer has any output voltage. The one I have is pretty clearly marked IGN on one terminal. I assume that would go to the ignition switch.
I tried removing the jumper bar that runs from one gauge to the other on the hot side in my cluster and hooking them up individually and also tried reversing the connections on the gauges, except the gas gauge since it was working correctly.
No dice on any of those combinations, especially now that the regulator is dead.
I have seen all of the gauges move through their entire range, so I know that they are responding to something.
Could it have anything to do with the sending units? I'm running a late 60's 289 with appropriate sending units for that motor. Is it possible they just plain aren't compatable with the gagues?
Check for continuity (0 Ohms) between the sender and the gauge. To test the gauges, disconnect the leads from the terminals and apply 1.5 Volts DC across them. The gauge needle should rise to the center of the range and hold. That tick mark at the base of the gauge face marks the center. The needle should be close to center; if not, replace the gauge.
Check for continuity (0 Ohms) between the sender and the gauge. To test the gauges, disconnect the leads from the terminals and apply 1.5 Volts DC across them. The gauge needle should rise to the center of the range and hold. That tick mark at the base of the gauge face marks the center. The needle should be close to center; if not, replace the gauge.
Continuity is no problem, I just ran new wires with the new senders. I'll check the gauges in the morning. Thanks for the info.
doug
The problem is almost certainly the senders not being compatible. The old flathead era temp senders were bimetal, pulsing type, while newer stuff is more like a variable resistor. If you use the old senders with the new engine you should get correct readings. You may need to use a trimming resistor to get them to read correctly.
My IR was reversed for a month and didn't smoke off; makes me think your new senders have a real low resistance or something.
The problem is almost certainly the senders not being compatible. The old flathead era temp senders were bimetal, pulsing type, while newer stuff is more like a variable resistor. If you use the old senders with the new engine you should get correct readings. You may need to use a trimming resistor to get them to read correctly.
My IR was reversed for a month and didn't smoke off; makes me think your new senders have a real low resistance or something.
This all makes me a little sad. The original senders are long gone and before my time with the truck. The engine swap happened about 20 years ago and then the truck sat in a barn for about 15 years and waited patiently for me to find it and bring it back to life.
Maybe I should have left well enough alone and stuck with the vintage SW gauges that used to hang under my dash.....