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Ok so I'm trying to fix my temp sensor on my 69. I have the factor console gauges in my car. From what I know about the history of the car I would believe it to be factory. The gauge never seems to work. However when I ground the wire at the sensor the needle on the gauge goes halfway between the C and the H. Never any further. This is the first issue.

Secondly I have aluminum intake with aluminum heads, and the sender is installed in the front of the manifold. Once I have the gauge working properly will this stop the sender from working correctly?

Thanks,
Jake
 

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There are different sending units for gages and warning lights so you probably need to make sure that you have the right sending unit. Depending on where you have it mounted in the manifold, you may see more fluctuation as the thermostat opens and closes versus in the head where the temp is likely a bit more constant.
 

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IMHO, a temp gauge wants sender in head and temp light sender use the manifold near T stat. Each sender is specific to a gauge or a light

My gauge temp sender PS head between cyl 6 & 8
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Temp light (dash) sender on intake manifold
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Factory Gage Sender should be about:
Cold 400 OHMS
Mid Range 100 OHMS
Hot 50 ohms

Use a DDM or equal to test the Sender when Motor is garage cold and monitor as it warms up, a proper sender for a gage equipped car should vary as the coolant temp rises. Use a VOLT-OHM METER to test using the resistance range appropriate to just do a simple non intrusive validation to start. Yes Disconnect the Green wire and test the sender alone, ie. Black meter lead to good ground and red to threaded stud on sender.
 

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I did the prescribed test and the ohm resistance reading on the sender went down as the motor warmed up. When I connect the green wire to the sender, the reading doesn't seem to show much resistance. Can this indicate a faulty gauge or incorrect gauge wiring?
 

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I installed a 81.5 Ohm resistor across the two posts where the pink and green wires connect on the gauge. The AAW schematic shows the pink wire connecting to the outside blade terminal and the green one to the inside terminal. Hard to tell which post is the negative for the green wire. Thanks for the response.
 

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An update. I checked the ohm reading on the sender and noticed this:
Without key on and green wire not connected - 790 reading.
Without key on and green wire connected - 12.
If the key is turned on and green wire connected, then the reading is 1 or 0.
The gauge does go to the hot side when the wire is grounded. Any ideas?
 

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Does anyone have the initial ohm resistance for the correct sender without the green wire hooked up? I purchased a new one from Heartbeat City and it shows around 1200. I checked the sender body to ground and it is 0-1 ohm Thanks
 
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