Factory slatnose voltmeter fix?

[Kevin 007]

My factory voltmeter on my 84 never moves, always stays put on the center line regardless if the engine is running and it doesn't even drop below center while im cranking it over. My alt charges at 13.9 and always has and im not too worried about it.
I would just like to glance down at the factory gague once in a while and see it in the "charging" range. I have enough aftermarket gauges and switches on my dash and don't want to install an aftermarket voltmeter to clutter it up even more. So im wondering if there is a fix for the factory gauge.

Did any of the factory slantnose voltmeters ever work? Or is this typical behaiviour just like the oil pressure and temp gauges not beign true read-outs.....

 

[SparkandFire]

It's actually an old-school "CHARGE" ammeter, like you'd see in one of the gauge clusters on the General Lee...

It indicates whether current is flowing OUT (Charge, good) of the alternator into the batteries, or INTO the alternator (Discharge, bad)

The circuit that allows this to work is somewhat of a mystery. Sort of how the old humidity gauges used to work off a specific length and diameter of horse hair to tell how much moisture was in the air.

There is a fusible link with a "known" resistance leading from the field wire on the alternator to the starter solenoid. One end of the link is wired back to the meter on one side of the gauge, and the other is wired to the other side of the gauge. The coil inside the ammeter deflects depending on how much voltage is apparent on either side of the link. It's a very old technology and very susceptible to things like corrosion, wire age, even temperature.

If all your fusible links are intact, there could be a bad connection, or an open coil in the gauge.

I just abandoned mine on the '85 in favor of a much more sophisticated... Like this...

http://www.amazon.com/Equus-3721-Battery-Charging-Monitor/dp/B000EVWDU0

 

[smolkin]

Don't mean to hijack but is the bricknose meter also a funky ammeter? Mine has never worked. And Kevin, the meter on my old '84 also never worked, but if you are having trouble with all the other factory gauges too it could be your IVR, the little metal box thing on the back of cluster. That is, unless the volt meter isn't on the same circuit, which is what it sounds like.

 

[SparkandFire]

Bricknose and OBS went to Voltmeter style gauges...

 

[hesutton]

That ammeter is just there to fill a hole in the dash. Completely useless. Have three 83-86 Fords, that waste of space gauge has never moved in any of them. If you really want to know some information about your charging system ....... get a good voltmeter. Got one in all my trucks (even the gasser).

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Heath

 

[Dsl_Dog_Treat]

It will move if the alternator dies. That's about it.

 

[franklin2]

It's actually an old-school "CHARGE" ammeter, like you'd see in one of the gauge clusters on the General Lee...

It indicates whether current is flowing OUT (Charge, good) of the alternator into the batteries, or INTO the alternator (Discharge, bad)

The circuit that allows this to work is somewhat of a mystery. Sort of how the old humidity gauges used to work off a specific length and diameter of horse hair to tell how much moisture was in the air.

There is a fusible link with a "known" resistance leading from the field wire on the alternator to the starter solenoid. One end of the link is wired back to the meter on one side of the gauge, and the other is wired to the other side of the gauge. The coil inside the ammeter deflects depending on how much voltage is apparent on either side of the link. It's a very old technology and very susceptible to things like corrosion, wire age, even temperature.

If all your fusible links are intact, there could be a bad connection, or an open coil in the gauge.

I just abandoned mine on the '85 in favor of a much more sophisticated... Like this...

http://www.amazon.com/Equus-3721-Battery-Charging-Monitor/dp/B000EVWDU0

The "fusible link" you write about is actually called a shunt. It's not old technology, it's still used today, and is the only way (besides a current transformer on a AC circuit) that you can monitor large amounts of current flow on a small guage.

After saying all that, the others are correct, they never did work very well, even when new. Sorry.

 

[Kevin 007]

Yeah Ok, thanks for the input guys. I won't be installing an aftermarket voltmeter just because I have enough clutter on my dash with other items. Just would be nice to get the factory gauge that is already in place; to show some sign of life. Just to know that there is some kinda charge coming from the alt. My level of concern would then only rise if that ammeter gauge suddenly read a "no-charge" or a negetive figure.
I'll give all my fusible links a good once over to see if anything obvious jumps out at me...

 

[MIDNIGHT RIDER]

The ammeter in the 80s Ford is not wired as a true ammeter and that is why the needle hardly ever moves.

A true ammeter has the entire current of the alternator routed through it between the accessory junction and the battery.

When current is being pushed into the battery, the needle moves to the CHARGE side, the stronger that current, the more the needle moves.

When accessories are using more current than the alternator can handle, then the needle moves to the DIS-CHARGE side.

Old Mopars did have true ammeters and were the source of many dash fires once the connections became old, loose, and corroded; also, many alternators were discarded when the real problem was faulty connections at the ammeter.

Once alternators got bigger than 35-amp, the load became more than low-budget ammeters could handle, hence the change to volt-meters.

A good volt-meter is a vital tool for monitoring battery and alternator health and well worth any space it may require.

Compare the readings of any volt-meter with a couple of known-accurate hand-held meters to get an idea what the numbered readings actually are; it is rare to find even an expensive one that is dead-on accurate; many are off by as much as 1-1/2-volts, either high or low.

For years, the SunPro in my truck was dead on the money; then, for reasons known only to the gauge itself, it started reading about a full volt lower than actual.

The readings are steady and consistent, so I just allow for the discrepancy.


These dis-crepancies of electronic gauges are why the manufacturers quit putting actual numbers on the gauge faces.

Most factory gauges are very accurate and consistent, once one learns what the needle position is in actual number readings.