Coming close to finishing up the Model A, but the temp guage won't cooperate. I'll attach pics, but basically I have 1 wire going from the sender on the head to the temp gauge, 1 wire going over to the other sender. The gauge doesn't read temp, its either all the way right or all the way left (if I switch the wires)... All my other gauges work, but this one's fighting me. Thanks in advance for your advice.
I am no sparky but it looks like you have a temperature sender in one head and maybe a thermo fan switch in the other head? And if you are running two senders you may need to work out a way to switch circuits if running one gauge. Others with more experience will chime in I am sure
Agree with Harry here. Put the two wires together on the same terminal and see what happens. You should get the temp of the head with the single terminal. There was a post on here a little while back about running two senders to one gauge so that you could check the temp on each head separately. https://jalopyjournal.com/forum/posts/12878721/
Yep. Since your using a newer gauge, I’d search for one that reads two senders at once. Or install two singles. That was the drawback on the original tube style senders from the mid to late 30’s. They only read half the coolant temp in the divided jackets.
I believe with the original Ford senders, the one with 2 terminals is the one that works the gauge in the left head and the one that goes in the right head is an on off switch that pegs the needle if the head gets too hot. These may not be compatible with a modern gauge, plus may not work correctly on 12 volts.
The original Ford senders will work only with the 6Volt OEM Ford temperature gauge that came with the 6 Volt OEM Ford sender. The same holds true for the flathead gas tank sending unit and gauge. They will not work on 12V unless you reduce the incoming voltage that feeds the gauges (or gauges) to 6 volts. The reason is because the operating principle of the flathead sender is NOT based on OHMS LAW. Instead, it uses a bi-metallic strip inside the sender that heats up and works with the Ford gauge. You can install a CVR (Constant Voltage Reducer) to reduce the 12V feeding your gauges to 6V. That way you can still use 6V to operate your gauges if you convert your car to 12V. Here's some good reading: https://www.jalopyjournal.com/forum/threads/flathead-water-temp-sender.453115/ and https://www.ford-trucks.com/forums/999794-flathead-temp-sending-units.html and this: https://www.fordbarn.com/forum/showthread.php?t=315958&highlight=temperature+sender You must also read this: https://www.fordbarn.com/forum/showthread.php?t=48622&highlight=battery+gauge+12+volt+conversion
^^^^ Ford gauges of that era used King Seely senders. You will need to get a sender compatible with your Auto Meter gauge. Could get two senders and use an A-B switch to read each head, or use two gauges.
Wow, my brain hurts... I think I'd like to stay with the gauge I have and run a switch, any advice on where I can get new senders from? Also, does it require a special switch? Or any A/B type switch will do? Thanks for all the help
Auto meter should have supplied the sender info needed with the gauge, or look up the model # of the gauge. Any A-B switch rated for the amperage will work. I can't image more than 5 amps. As @BJR stated, the original 6V set-up used one sender to monitor temp, and the other one is a high temperature on switch only. The idea being as long as both water pumps worked, the temp should be the same on both sides. Should the temp get high and the temp sender fails, the switch sender would peg the gauge.
Auto Meter should be able to supply you with proper sending units for your gauge. A separate wire from each sending unit to a switch, to switch the gauge from sender to sender (will only read one sender at a time). I've done a few this way. I've also done some that had 2 temp gauges and 2 separate senders so both sides read at all times.
So far so good, thanks for the advice, got 1 proper sender in and it's all good. Now I just have to figure out the dual and a switch.
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