amp meter
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
To put it simply,
A Shunt is basicly a power tap or power splitter.
In the ammeter application it allows full charging power to the battery from the altenator, but it only alows around 50Mw or so to go through the ammeter.
It's simular, but not exactly like the industrial television power distribution tap.
In a hotel with tv antennas and fifty televisions you need to amplify the power output to around 50 db's.
You need to split the wire coming from the distribution amp to each tv. If you use a regular splitter it will split the power evenly. 25 to each side. 25 DB's will go to the 49 tvs and 25 dbs will go to the one set you split off.
One tv set cannot handle 25 dbs and overloads and you get no picture.
But if you use a Industrial 1 DB, TV power tap only 1 db is sent to the one tv set, and the 49 db's are sent down the line to the other 49 sets.
A shunt works simular, but it works both ways instead of one way like the tv example.
The shunt alows almost all the current to go to the battery from the altenator, but taps off enough current, to operate the ammeter without overloading it and causing a fire.
You should be able to get a shunt at automotive stores, or electronics places.
A Shunt is basicly a power tap or power splitter.
In the ammeter application it allows full charging power to the battery from the altenator, but it only alows around 50Mw or so to go through the ammeter.
It's simular, but not exactly like the industrial television power distribution tap.
In a hotel with tv antennas and fifty televisions you need to amplify the power output to around 50 db's.
You need to split the wire coming from the distribution amp to each tv. If you use a regular splitter it will split the power evenly. 25 to each side. 25 DB's will go to the 49 tvs and 25 dbs will go to the one set you split off.
One tv set cannot handle 25 dbs and overloads and you get no picture.
But if you use a Industrial 1 DB, TV power tap only 1 db is sent to the one tv set, and the 49 db's are sent down the line to the other 49 sets.
A shunt works simular, but it works both ways instead of one way like the tv example.
The shunt alows almost all the current to go to the battery from the altenator, but taps off enough current, to operate the ammeter without overloading it and causing a fire.
You should be able to get a shunt at automotive stores, or electronics places.
Fleet Mechanic
Joined: Feb 2007
Posts: 1,326
Likes: 48
From: Middle TN
To back track a little,
On the main harness, can't you just change out the plugs from light to gages. The number of wires and and wire colors are the same if I'm not mistaken, The problem is they are in different positions for the circuit boards being different and of coarse the plug is longer for gages.
The wires can be easily removed from the plugs by using a small thin screwdriver and they will pop out with out damage if you are careful.
Then you could cut the plug and 3 inches of wire from a gage model truck in the junk yard and use this as a reference. Take each color of wire out of the light plug and place it in the gage plug one at a time in the correct position (You would have to remove the gage wire stub first one at a time of course). You would use the gage plug wire colors to make sure you get them in the correct position.
By the way, the plugs have numbers on each slot to help you know what slot it is.
This would save time from having to swap out main harness. I haven't tried this but I don't see where the problem would be. I have studied the wiring diagrams and it looks like ford used the same colors for the same functions as best I can tell.
Can anyone see a problem in this? Or has anyone tried this????
On the main harness, can't you just change out the plugs from light to gages. The number of wires and and wire colors are the same if I'm not mistaken, The problem is they are in different positions for the circuit boards being different and of coarse the plug is longer for gages.
The wires can be easily removed from the plugs by using a small thin screwdriver and they will pop out with out damage if you are careful.
Then you could cut the plug and 3 inches of wire from a gage model truck in the junk yard and use this as a reference. Take each color of wire out of the light plug and place it in the gage plug one at a time in the correct position (You would have to remove the gage wire stub first one at a time of course). You would use the gage plug wire colors to make sure you get them in the correct position.
By the way, the plugs have numbers on each slot to help you know what slot it is.
This would save time from having to swap out main harness. I haven't tried this but I don't see where the problem would be. I have studied the wiring diagrams and it looks like ford used the same colors for the same functions as best I can tell.
Can anyone see a problem in this? Or has anyone tried this????
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
There are some major problems to overcome, if you don't swap out the main harness, and altenator harness.
1: The number of wires between the Ammeter, and Warning lamp Instrument cluster plugs are different.
2: The altenator harness between the altenator and the battery is wired different. Example, including a shunt so the ammeter doesn't catch fire.
3: The voltage regulator is wired up different, between the two. Example, the stator wire is hooked up to the voltage regulator on warning lamp vehicles, it is not hooked up to the voltage regulator on ammeter equipped vehicles.
4: The ignition Switch is wired up different. Example, the ignition switch hooks into the Alt. warning lamp with the key on, engine off to tell you if the light works. On ammeter equipped vehicles it is not hooked up like that.
And that's just the differences on the top of my head. There is a lot more differences.
Don't attempt this type of project unless you change out the harnesses, (recomended), or you are prepared to do a heck of a lot of re-wiring. (not recommended, because of the number of circuts that need to be changed, or altered).
Hope this helps.
1: The number of wires between the Ammeter, and Warning lamp Instrument cluster plugs are different.
2: The altenator harness between the altenator and the battery is wired different. Example, including a shunt so the ammeter doesn't catch fire.
3: The voltage regulator is wired up different, between the two. Example, the stator wire is hooked up to the voltage regulator on warning lamp vehicles, it is not hooked up to the voltage regulator on ammeter equipped vehicles.
4: The ignition Switch is wired up different. Example, the ignition switch hooks into the Alt. warning lamp with the key on, engine off to tell you if the light works. On ammeter equipped vehicles it is not hooked up like that.
And that's just the differences on the top of my head. There is a lot more differences.
Don't attempt this type of project unless you change out the harnesses, (recomended), or you are prepared to do a heck of a lot of re-wiring. (not recommended, because of the number of circuts that need to be changed, or altered).
Hope this helps.
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Ammeter shunts are used for quite a bit of stuff, including solar panels, windmills, etc...
Not sure if Ford would have any, never asked. Numberdummy would know.
Also try Radio Shack. They used to carry a lot of electrical components in the past, before they became another cell phone retailer.
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Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Only wire missing on the diagram is the Black/Yellow wire that feeds the Ignition switches main power. It would be placed where the Red/orange wire from the ammeter, and the Yellow/Black wire are spliced together.
The Green/Red wire also eventually ends up at the ignition switch (Splices into the Red/Green wire that comes out of the Ignition switch) but is hot only in RUN.
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
Originally Posted by okwaho1650;66
49400
49400
Cool what
voltage should I be
getting on the
ammeter
wires
voltage should I be
getting on the
ammeter
wires
altenator, you
should have a 50mV
(Millivolt) shunt.
Depending on
altenator output,
not more than 50mV
on the ammeter
wires. around .05
volts.
This will explain better.
http://en.wikipedia.org/wiki/Ammeter
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
If you do a search for DC Ammeter Shunts on the internet, a plethera of aftermarket shunts pop up. They are of different design to the one on the truck obviously, but they do the same job.
