1947 Super Deluxe Temp Gauge Problem

[RKS.PA]

My electric temp gauge is stuck on H. I've replaced the two sending units in the block to no avail. How do I trouble shoot the gauge and if bad, is Morris Instruments in Portland a good option?

Thanks for the help.....Dick

[39topless]

If it's stuck on H it is probably electrical. Check your connections.

[Kurt in NJ]

No connection ---have you tried jumping the 2 terminal sender, it is just a temperature switch that goes open at some temp like 212

[Old Henry]

As shown in the following wiring diagram, the route of electricity for the temperature gauge circuit is fairly simple.



The current comes from the connection of the oil and gas gauge through the temperature gauge, then through the left block sender to the right block sender then through that sender to ground. So, you can start at one end or the other to find the break. You can use a 6 volt test light or volt gauge. I think it's easier to start at the right sender. Disconnect the wire at the sender and run the current that should be full from that to ground through the test light or volt gauge. (Of course, you have to have the ignition switch on.) If the current is there that sender is bad and needs replaced.

If it isn't there go back to the first terminal of the left sender (the one that doesn't go to the other sender.) If the current is there then that sender may be bad. You can actually bypass it by connecting the two wires together there to leave that out as a possible problem.

If no current is at that wire to the left sender you next go to the terminal on the gauge that does not go over to the other gauges. If current is there the problem is in the wire from there to the left sender. If it isn't there, check the other temperature gauge terminal to see if it's there. If it's there but not on the other side the gauge is bad and needs replaced. Here's an NOS gauge on ebay: http://www.ebay.com/itm/NOS-OEM-Ford...5Uw8ov&vxp=mtr If no current is on that side then the short wire from the other gauges is at fault.

That's really the procedure for diagnosing any electrical circuit.

Good luck and let us know how it went.

[meric42]

First thing is to check that you have battery voltage on the dash unit with the ignition on, you can do this with a test light of multimeter.

Then you need to check the function of the gauge. You can short the single terminal temp sender to ground/chassis with the ignition on and someone to watch the guage needle. If the dash unit moves then your fault is in the sender unit/s, if not then the fault is probably the Dash gauge itself.

Hope this is of some help?

Meric.

[Graeme / New Zealand]

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Follow this. I did and if your temp probes are rooted make sure your replace them with good US made second hand ones. I used some foreign made repops and they both failed me.

If you can't enlarge this by saving it into a folder and opening it and enlarging it send me a pm and I'll email it to you.


GB

[RKS.PA]

Thank you, guys, I'm trouble shooting this a.m. and will let you know what I find.

Dick.

[RKS.PA]

Eureka!!! The new right side sending unit I got from Mac's was bad....I also got another one from Mac VanPelt and put that one in using Craig's trouble shooting guide. I went through all the steps, starting with the right side, but I continued all the way up to the back of the temp gauge to satisfy myself that that gauge was not the problem.

Thank you all, and especially to "Old Henry" for proving once again what an incredible resource this Ford Barn is.

Dick.

[Bruce in southern OH]

Very nice Car !!!!!!!!!! Happy Thanksgiving