Went to the car show and swap show Saturday with the 52 F1 truck and the gas and oil pressure guage decided that they would quit working. Temp and amp guage is working fine. Anybody have any ideas on what is going on. I checked the wires and changed the fuse several times but everytime you turn the key on it blows the fuse. I'm thinking I have a short somewhere on those two guages.
Thanks for the feedback.
LBrauer

 

I'm too new to post a photo but Julie posted a reply here:
https://www.ford-trucks.com/forums/1...ring-help.html
Scroll down to see the diagram of the gauge. The Ammeter gets its power directly from the battery and the Temp gauge get their power directly from the ignition switch. If they work I'd suspect that the strap from the Temp gauge is corroded and is somehow insulated from the power. Power flows through the gauge to the sending unit that makes a circuit to ground through a variable resistance thereby making it possible for the gauge to register change. I would think it highly unlikely that both sending units are defective, that's why I suspect the strap.

 

I don't have a problem with the ammeter or the temp guages it is the gas and the oil guages that quit working. It blows the fuse everytime the key is turned on. As I said the temp guage and the ammeter guage works fine.

 

YEP!

Check the wires for chaffing where they go through the firewall, and anyplace they cross a cable or a hot spot. Short may not be visible to the eye.

With the ignition off, disconnect the wires to those two gauges at the senders. Take your meter - set at 0 ohms - and touch the end of one wire with one lead and the other to a good ground. If the needle deflects, that wire has the short - somewhere.

 

Thanks Julie

 

Actually, that may not be entirely true now that I think of it. As I recall, you have a single sugar cube reducer that powers all three gauges (amps doesn't count it's independent).

I guess you must have run a new seperate power circuit for your temp gauge especially if it is still working with the fuse blown for the other two. Yes? You had to have done something there..........

If that's true then yes the wires leading to the senders might be shorted but also your power supply wire going up to the sugar cube might be shorted too.

 

I have a similar issue. I have a 52 with the OHV 6 cyl. My fuel and amp gauges work, but the oil pressure and temp gauges do not. They'll "work" when the truck is started, but then gradually go down to zero.

I used a spare instrument gauge assembly cluster and ran jumper wires from the temp sender and battery ground to the spare gauge assembly and the temp gauge seemed to work properly.

Any ideas what could be the issue in mine? Does anyone (Julie ) have a wiring diagram for the gauges and the proper color the wires need to be? I may have the wires crossed or spliced wrong. Not sure what the PO did when he installed a new wiring harness.

Thanks.

 

Hi Ilya,

I sent you an e-mail with the gauge wiring and some explanations about the flow.

Remember if the circuit on the temp gauge is not working, it doesn't go down to "C" it jumps up to "H"!!!!!!!

Power supply to all three should be the same - wire in from the ignition switch then from gauge to gauge via a metal shunt.

Check the shunts/nuts/connections for tightness and generall cleanliness. Also, since the gas works, that little voice in the back of my mind is asking if you used teflon tape on the threads of the temp and oil senders (a "no-no"), or if your engine ground is sufficient!

I sent this to you already but will post it again for the forum:

 

Ilya, not at all uncommon for the temp and oil senders to be bad.

 

Thanks Julie and Ross. Armed with this info, I will pull a few spare instrument clusters out of storage and will attempt to find a fix with all the info presented.

Thanks for the email, Julie.

 

Well yes I went and looked again at the truck turned the key on and the temp guage doesn't work either so they are all hooked up to the same fuse in the fuse box. I thought it was working but come to find out it is not. Won't move to cold with key on. I'm going out there to see if there is a short somewhere in the power wire. Is there a way that I can check the little cube reducer on the top of the guages to see if it went out?

 

Check all the cheap paper insulators between the bar straps connecting the gauges. It doesn't take much for one to wear thru or rip and you have an instant short-to-ground.

What little cube? Do you run 12v with a constant voltage regulator? Or are you talking about the circuit breakers?

 

Larry has one of those little cube single voltage reducers (ok, a CVR) that he is powering all his gauges off of.

There is a way to test it with the meter. Just run power up to it and touch it with the red lead of your meter and touching the black lead to ground. The meter should be set to read 0-50 Voltd DC. When you do this test it should read about 6 to 7 volts.

But I don't think it's your problem. If you are popping fuses, where it was working before, chances are highest you've chaffed a wire that is now touching ground or have two wires chaffed and touching and one goes to ground.

There's an easy way to tell which one it is. First, remove the power wire from the back of the little cube, and the wires that go out to the sending units of each gauge at the gauge. Replace the fuse with a good one.

Now turn on the power and touch the power wire to the cube where it normally attaches. If the fuse blows the short is on that wire coming up from the fuse block to the cube or the wire coming off the other side of the cube running to your first gauge.

If it doesn't blow the fuse, turn off the power and hook that one wire back up where it belongs. Turn the power on and check the fuse again.

Then with the power still on, touch the lead running out to the gas tank sender to the post it goes on on the back of the gas guage. If it doesn't blow the fuse, turn off the power and hook it back up to the back of the gas gauge. Turn the power back on and check that the fuse does not blow and your gas guage registers correctly.

Repeat this with process with the oil pressure gauge wire then the temp gauge wire. Eventually when you touch one of them, the fuse will pop. When it does, the wire you just touched has the short on it.

Replace that wire and find out where the chaffe is that caused the short and wrap your wire bundle there for added protection. Probably at the firewall.

 

Thanks Julie that was what I was thinking of doing since I can't find the short as of yet. I will try your method tomorrow when I get some help from my son.

 

I'd also get some help from Samual Adams!

Good luck!