I have a problem with the temperature reading backwards.

54, 12 volt, 312. 10 years ago when I got the car (had 239 in it then) the wiring was in tough shape (already converted to 12 volts). I put a new harness in it, everything was great including the gauges.   I put one of the  57 and later Ford gauge voltage reducers in it.  Everything turned out fine.  Been running it for ten years.  Temp gauge always read about 1/3 from cold.  No over heating problems.  The sender was the 57 type.  The gauge stopped reading this season, sender went bad , replaced it with a new sender of the same type.  Gauge then read at the end of the long line on the hot side (still no over heating problem).  I decided to replace the sender with a 54 one (one that I had) .  Changed everything over (including the "bung"):.  Gauge now reads backward - didn't change anything under the dash.  Now reads about the same (needle is on the "E") but it is on cold with the ignition off, goes to hot when the ignition is turned on and goes to the left as engine warms up.  Radiator thermometer reads about 170 degrees with engine fully warmed up.

Question - when some one had the same problem others have suggested to reverse the wires on the gauge.  Will this screw up the gauge if I do this?  Since it was working ok before, I am hesitant to reverse the wires.

Any other insight into the problem?

Thanks


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

I don’t remember where it was, but someone with a gauge problem just pointed out that in come cases, the resistance went up instead of down on certain senders. I think it was a flathead sender in question.

Most gauges are bimetal, and reversing them wouldn’t hurt. I’m not so sure about the King Seely(sp?), but I also don’t know it that’s what was in a 54. If no one here knows, that might be a good question on the Ford Barn. Lots of early cars with different (later model) engines installed. They have a social group your 54 would fall in.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

As far as I know 1957 to 1962 Ford used the same water temperature sending unit & gauge value.
The senders have a high resistance ohm value when cold apx. 180 to 200 plus ohms.
When the sender is heated the ohm value decreases. 220 degrees will equal apx. 11.5 to 13.5 ohms.
The water temperature & fuel gauges are not polarity sensitive.
Make sure your constant voltage regulator is running at half voltage 6 volts. They are biemetal & pulsate to cut voltage. If your fuel gauge functions correctly your constant voltage regulator is ok.
You can test your temperature sending unit with a little rigging : ohm meter , heating water (boiling) Will get you close to correct ohm values.
As I remember NAPA # TS 6464 was for 1957 to 62 Fords...?? I can double check # when I get to the shop today.

That car would have been built as a 6volt positive ground and is now 12volt negative ground. Perhaps something (sender)  is polarity sensitive  causing the backwards read ?