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Discussion Topic:
Temperature gauge
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Carcheologist |
06-20-2021 @ 4:07 PM
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New Member
Posts: 132
Joined: Jan 2016
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Where should the temp gauge needle be pointing when the ignition switch is turned OFF - toward COLD or HOT?
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sarahcecelia |
06-20-2021 @ 5:41 PM
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Senior
Posts: 1183
Joined: Mar 2013
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Toward COLD!!
Regards, Steve Lee
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40 Coupe |
06-21-2021 @ 7:27 AM
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Senior
Posts: 1674
Joined: Oct 2009
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Toward Hot. When you turn the ignition to ON the pointer will move to cold and then slowly move with the engine temperature.
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TomO |
06-21-2021 @ 7:42 AM
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Senior
Posts: 7250
Joined: Oct 2009
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40 Coupe is correct. Why do you ask?
Tom
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Carcheologist |
06-21-2021 @ 7:53 AM
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New Member
Posts: 132
Joined: Jan 2016
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I've been trying to get the gauge to read correctly and suspect my sending unit is bad. The needle moves to full HOT when the ignition switch is turned to OFF, then moves way past the cold mark when turned ON. It doesn't move toward HOT as the temperature increases. Looks like my sender is bad and needs replacing. Any thoughts?
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RAK402 |
06-21-2021 @ 10:04 PM
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Member
Posts: 436
Joined: Jul 2015
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It seems to me there is a test for the dash unit, using a gas gauge sending unit in place of the temp sending unit, outlined in the 1938 to 1940 Complete service bulletin books. Someone outlined it here on the forums, and once in the dim, dark past, I did it and it worked (my repro sending units were not made correctly). Update! I found the test: Operation 10883-A (page 314 of the service bulletin book). I can scan it and post it for you, if that will help.
This message was edited by RAK402 on 6-21-21 @ 10:19 PM
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Carcheologist |
06-22-2021 @ 8:01 AM
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New Member
Posts: 132
Joined: Jan 2016
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RAK402, Thanks for the tip! I have the service bulletin book and will check it out.
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TomO |
06-22-2021 @ 8:32 AM
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Senior
Posts: 7250
Joined: Oct 2009
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It sounds like your dash unit is working correctly. Your problem could be in the sending unit or the wiring. Do a quick check of the wiring by connecting a jumper from the sending unit with 1 terminal to ground and then turn on the ignition switch. The needle on the gauge should move towards HOT. The fuel sending unit test will check out thhe gauge further. The new replacement sending units do not work the same as the original units, so I would look for an original King-Seeley unit. Your best bet for one of those is another Ford guy or swap meets.
Tom
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cub 45 |
06-22-2021 @ 10:48 AM
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Member
Posts: 46
Joined: May 2021
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what would happen if you reverse the wires on the gauge ?
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Carcheologist |
06-22-2021 @ 11:04 AM
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New Member
Posts: 132
Joined: Jan 2016
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Here's an update to my testing efforts: Swapped out several old sending units, with various states of unsatisfactory results. With one of them, the needle retreats halfway towards COLD when the ignition switch is turned on and then rapidly advances into the HOT range as the temperature increases. After registering well into the HOT position on the gauge after driving for a while, the needle falls back to the COLD position and stays there until the car cools completely down. Others show the needle to move quickly past the COLD mark as soon as the switch is flipped on and then after a short time of driving, it advances to full HOT! It seems the old sending units are giving me various readings, but I don't think the gauge is at fault; at least not yet. I have ordered a new sending unit from Third Generation Automotive and we'll see how that plays out.
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