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Discussion Topic:
Temperature gage
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Jone |
09-17-2016 @ 7:31 AM
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Member
Posts: 38
Joined: Jul 2015
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My 47 Merc was, for some unfathomable reason, converted to 12 V by the former owner. His half hearted (hearted was not my first choice of words) job has caused me many problems. He had also replaced the original fan with an electric fan, probably because the alternator is mounted where the fan should be. I have installed Runtz voltage reducers to each of the gauges. When I start the car the temp gauge immediately goes to the halfway position and after a mile or two of driving it goes all the way to the hot side. I checked the temperature of the water in the radiator and it was 180 degrees. I assumed that the problem might be with the sending units, so I looked in Mac's catalog for replacements and they are rated for 6 volts. Would that cause the inaccurate readings? Would 12 volt units from a 56 Ford fit, and could that correct the problem of inaccurate readings? Thanks, Joel
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TomO |
09-19-2016 @ 8:36 AM
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Senior
Posts: 7256
Joined: Oct 2009
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Joel, you temperature gauge is not getting enough current. You may only need one Runtz connected between the wire coming from the ignition switch to the gauges. I have not converted a car to 12V so my answer may not be correct.
Tom
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Jone |
09-19-2016 @ 1:01 PM
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Member
Posts: 38
Joined: Jul 2015
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Thanks Tom. All the information I've read about these Runtz units is that one Runtz should be installed on each gauge, except the Amp Gauge. the Runtz is rated at 1.5 ohm resistance, 4 amp max load, 25 watts. I've also been told that each gauge draws about 1/2 amp, so one Runtz for all three gauges might work. Just about every problem I've had with this car has been related to the shoddy conversion job. I'll never buy another car that has been converted to 12v. Joel
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TomO |
09-20-2016 @ 7:24 AM
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Senior
Posts: 7256
Joined: Oct 2009
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I just read the Runtz description of the Runtz. It is not a voltage dropping resister, it is a 6 volt voltage regulator. You do need a separate one for each gauge, because the current draw for each gauge is different. It needs 10 - 16 volts input and outputs a steady 6 volts. You should have a Runtz connected to the right terminal of the fuel gauge, the left terminal of the oil pressure gauge and the right terminal of the temp gauge. The brass strip between the fuel gauge and the oil pressure gauge should be removed. If the gauge does not read correctly, check the input voltage and the output voltage. If they are correct, check the sending unit for a proper ground. The sending unit should not have Teflon tape to seal the threads. It does not nee any additional sealing compound. If they are not correct, replace the Runtz. Tom
This message was edited by TomO on 9-20-16 @ 7:25 AM
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Jone |
09-20-2016 @ 7:40 AM
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Member
Posts: 38
Joined: Jul 2015
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That is the way I set up the Runtzes. I will check the voltages, but it is difficult to get my head up under the dash, I don't have quite enough joints in my body. I find it is easier when I remove the front seat, only four bolts to remove and slide it out. That way I can lay down relatively flat and work more comfortably. Joel
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