1966 oil and temperature gauges stuck at 1/4

[Alecxix]

My gauges only move to about 1/4. But when I did the ground test they do move all the way to the right .

 

[Angry Bird]

My gauges only move to about 1/4. But when I did the ground test they do move all the way to the right .

It's been a long time since I had to deal with this but if I remember correctly, there is a small voltage regulator (black and about an inch square) under the dash near the firewall that reduces the power to 5 or 6 amps(?) to the guages. I am just getting ready to deal with this problem again after 20 years since I have the same problem again.

 

[Grahamp]

There is a 5 volt constant voltage regulator that supplies power to the gauges, this could be failing and will impact the gauge readings. Does the oil pressure gauge read correctly? If so, it may not be the regulator. Have you removed the gauges and cleaned the connectors which can easily corrode. Even though the gauges move all the way to the right when grounded, they may still not read correctly. Working gauges are very hard to find. I do know someone that can possibly fix them in Florida

 

[Grahamp]

A follow up - I thought I read that only two gauges were not working properly , not correct. Problem is almost certainly the 5 volt regulator . Replace it with a solid state modern unit, not expensive . I think you will have to pull the panel to get at the regulator, a good time to clean all the connectors and check the wiring

 

[jack-in-sac]

I am not sure how long Ford continued with the 5 volt regulators for dash gauges. In my early bird experience when the regulator fails the temperature gage goes to full hot and the gas gauge goes to full empty. the oil pressure gauge and ammeter gauges are not affected. as they are electrically sourced differently.
Good luck J.
Just a side not the ignition coils were still 6 volt for quite a while and that was the reason for ballast resistors and resistor wires in the ignition circuit.

 

[Alecxix]

A follow up - I thought I read that only two gauges were not working properly , not correct. Problem is almost certainly the 5 volt regulator . Replace it with a solid state modern unit, not expensive . I think you will have to pull the panel to get at the regulator, a good time to clean all the connectors and check the wiring

I just purchase the car a week ago, and only the volt gauge was working. After a lot of research I did all the corresponding test. I figure it was the sending units that were faulty but everything on the engine and components look pretty new. I went and replace the sending units anyway. That didn’t fix the problem, so then I had one last option pull the panel and replace the volt regulator. So I did I put a new volt regulator. I was happy to see that as soon as put the key into stand by everything work just fine. I remember I was jumping if joy lol. Because I didn’t wanted to get aftermarket gauges. Story is that they work fine for a few minutes then they drop to 1/4 I seen this on the gas and oil gauges. Temper ire kick in later when the car got warm. I fill the gas thank and my gauge reads half empty. I wondering now if there is a way to calibrate the gauges. But I’m happy with what I git at least I can get some sort of reading and feel more confident. Now is a normal thing were gauges only go up to 1/4 .?

 

[Grahamp]

No, you cannot calibrate the gauges. Have you cleaned the connectors on the back of the gauges. Assume you purchased a solid state 5 constant volt regulator and not a rebuilt original. Did you check the wire continuity to the new regulator, if the system works well but then deteriorates, it must be something to do with the electrical power to the regulator

 

[Alecxix]

No, you cannot calibrate the gauges. Have you cleaned the connectors on the back of the gauges. Assume you purchased a solid state 5 constant volt regulator and not a rebuilt original. Did you check the wire continuity to the new regulator, if the system works well but then deteriorates, it must be something to do with the electrical power to the regulator

Thank you for the info . But no I didn’t think of cleaning the connectors . That must be it. And the one I purchase looks just like the original volt regulator .

 

[Grahamp]

The voltage gauge does not run off the 5 volt constant regulator, but the other three gauges are dependent on a constant voltage of 5 volts, if this varies, so will the readout on the instruments.

 

[jack-in-sac]

I just purchase the car a week ago, and only the volt gauge was working. After a lot of research I did all the corresponding test. I figure it was the sending units that were faulty but everything on the engine and components look pretty new. I went and replace the sending units anyway. That didn’t fix the problem, so then I had one last option pull the panel and replace the volt regulator. So I did I put a new volt regulator. I was happy to see that as soon as put the key into stand by everything work just fine. I remember I was jumping if joy lol. Because I didn’t wanted to get aftermarket gauges. Story is that they work fine for a few minutes then they drop to 1/4 I seen this on the gas and oil gauges. Temper ire kick in later when the car got warm. I fill the gas thank and my gauge reads half empty. I wondering now if there is a way to calibrate the gauges. But I’m happy with what I git at least I can get some sort of reading and feel more confident. Now is a normal thing were gauges only go up to 1/4 .?

As another note; i believe you have an ammeter gauge not a voltage gage as original equipment.