Ford Instrument pannel voltage regulator

ONE37TUDOR · January 21, 2009, 11:33:58 AM

Can someone school me on exactly what this device does and what are the symptoms if it is not working? By looking at the wiring digram for my car (61 Galaxie) it appears that it only impacts the generator and oil pressure idiot lights? Is that true? Will all the other normal dash pannel operate normally without it?

Thanks for any help,

Scott...

wayne petty · January 21, 2009, 01:32:43 PM

the voltage regulator pulses current to the gauges... the gauge electrical wiring will burn out if full 12 volts is applied directly...

fuel gauge, oil pressure , temp gauges are supplied by the 5 volts or so output of this regulator..

on 3 leg versions... 12 volts on one leg... ground on another and the 5 volts output on the third...

do to the low currents involved... corrosion will make them do funny things... a little wire brushing of the connectors will do wonders sometimes...

if you need more info... keep posting.. i just got a huge stack of manuals... including a supplement for 61 to 63 ford galaxies and montereys.

i should put in... test the sending units with a digital ohm meter...
at the sending unit... then at the dash connector with it unplugged... should be about the same..

you can also ... but don't do it for more than a 30 seconds... pull the wire off the sender at the sender... with the key on... the gauge should swing all the way one way in 10 seconds give or take... then ground the wire... it should swing all the way the other way...

this article might explain it better

http://www.mustangandfords.com/techarticles/75259_instrument_electricity/index.html

enjenjo · January 21, 2009, 02:00:00 PM

On your car it affects the fuel gauge, and temperature gauge primarily.

ONE37TUDOR · January 21, 2009, 03:15:45 PM

Thanks for the information and the web site, very informative.
You may laugh at this but the reason I was asking the question to begin with is because of an interesting wiring accident I had.
When I installed a GM one wire alternator I removed the old generator and its voltage regulator along with the wiring harness that ran from the voltage regulator to the generator. I then ran a fused wire from the battery to the main power wire to the switch (Large Yellow wire)to complete the circuit that did go to the regulator. (Still following this?) All worked well but the old amp light no longer worked.

Then I installed an electric fan and while and while searching for a switched power source for the trigger wire for the fan relay I came across a small yellow/black stripe wire that once ran to the bottom post of the long gone voltage regulator. Connected it to the fan relay and all was well however as an oddity I did notice that when the fan was running the alt idiot light would just lightly come on? I kind of enjoyed this as it let me know when the fan was running. I still never put together that this may be connected to the insturment voltage regulator?
Now a year later and suddenly my fan just stops working, troubling shooting the problem (After my burns have healed) I found there was no trigger voltage to the relay. In attempting to trace the wire and finally looking at a wiring digram of that car I find that this wire connects to one side of the insturment voltage regulator? I still have not determined where the voltage went and all the other items in the dash are still working properly so I assume the regulator is still working? But why no voltage?

Now that you have read this rather long winded explanation you can stop laughing now.

Scott...

wayne petty · January 21, 2009, 03:58:16 PM

i have not dug into my wiring diagrams for the exact cars you have...

most of the later voltage regulators were hooked up and a single wire went to the gen light... the other side of the generator light went to switched power..

when the generator was not charging that end of the circuit was low... so the electons flowed through the bulb.. lighting it up... when the generator voltage came up the light went out.. as the voltage equalized on both sides.

so... if you want your light back... i bet that the bulb burned out..

was the point it connected to at the regulator a full 12 volts switched??? then through a bulb..

?

scott check your pm....

ONE37TUDOR · January 21, 2009, 05:05:03 PM

Thanks I will check the bulb for the alt circuit. I do not recall if the voltage was 12 or something less but I would not have have hooked to it if it were a lot less - like 5v or so? I have to believe it was at least 11 or so?
Scott...

wvcab · January 22, 2009, 06:47:17 AM

+1 on the bulb being burnt out.... the circuit (as in the fan relay)was using the bulb as a fuse.....

ONE37TUDOR · January 23, 2009, 08:34:06 AM

You gut's were right the light was burned out. So rather than reconnecting to something so hard to get to I just moved the trigger wire to the switched power terminal on the starter relay. Don't have my reminder light anymore but at least if something happens I can get to everything from under the hood.
Thanks for the help.

Scott...

The Paisano · January 26, 2009, 06:28:49 PM

the constant voltage regulator on the back of your cluster changes 12 volts to aprox.4.6 to 5.5 volts.by lowering the voltage,it sends this low voltage to your fuel and temperature gauges.this is the only function.
it you were to put a test light on either of these two gauges that is the connector at the sender units, you will notice that the light blinks off and on constantly and is not very bringht. this is normal,if it does not blink or contstantly on ,the cvr is no goodthis is due to the low voltage going to both gauges.If you were to put 12v to the system,it would bury the gauges and enentualy burn them up.
I been a fomoco tech for 36 plusyears and have worked on many of these systems.As far as I can remember,from around 61 till they started with elctronic clusters,there have only been 2 kinds on a ford.the differance is that the connectors are reversed.
This came out when they came out with plastic coated printed circuits in the back to connect the cluster goodies up Testing the gauges is another story and I can help you with that to.

"The Paisano"

38HAULR · January 28, 2009, 03:44:13 AM

My 66 Mustang,had high temp, fuel gauge readings,the constant voltage regulator had given up the ghost and was as much use as a dead dingo,s carcass on your doorstep. These are a bimetallic device that pulse to give an average of 5v. I just went to my local electronics shop, and grabbed a $1.30 three legged 1amp regulator, around the size of a fingernail. I actually grabbed 2 and paralleled them. One leg is input 12v. centre leg is earth, other leg is 5v output. I bolted them to a small heatsink and fitted behind the dash where the Ford unit sat