Charging problems

I have a 1986 Dodge 4X4 150 which will not charge. It has a new battery, new cables, rebuilt alternator (tested), and a new regulator. The ammeter does not work. The needle never moves. If it is burned out, will it
interupt the charging curcuit? I'm out of ideas. Ed
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Get any service manual, Chiltons, Motors, whatever. Follow the test procedures. You will need a voltmeter. My Chilton's covers 89 to 91 Dodge trucks ONLY. It's mostly copies of the factory manual and is well worth the money. (Part no. 8166.) Got it at Wal*Mart.
Al
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Thanks Al. I've done the tests in my Haynes manual. Nowhere does it mention anything about the ammeter. Ed
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Poorman wrote:

An ammeter measures the magnetic field around the wires and gives an indication based on magnetic field strength, which is proportional to current flow.
On my 79, I pulled the bad ammeter out when I measured battery voltage at 12.7 Volts and the ammeter didn't show any charge. I modified the dash insert to hold a similar sized voltmeter. I picked up my system voltage from the connection I made when I joined the two ammeter wires together( Don't forget to insulate this connection!!!)
Budd
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Poorman wrote:

See: http://www.madelectrical.com/electricaltech/amp-gauges.shtml and http://www.misterfixit.com/dedbatt.htm
--
Ken



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Hi Ed,
To answer your question, yes -- if the ammeter is open, you will get no charging current into the battery. However, it's likely the ammeter itself isn't open. Assuming you don't have a factory 100A alternator setup, I'd start by checking the connections on the firewall where two large wires pass thru, from the alternator and to the battery. Even a few ohms of resistance will severely limit the current supplied by the alternator.
At the connector assembly, check connections for the larger two wires that pass thru there. One comes from the alternator (12ga black), and one goes to the battery (12ga red). Unplug the connector on the engine bay side and inspect the terminals -- there should be little or no oxidation and no evidence of heating. If the connections have produced any significant heat, the plastic connector housing tends to melt. http://www.madelectrical.com/electricaltech/amp-gauges.shtml shows this.
If any pins are burned, they should be replaced -- the dealer will have replacements. If you don't care about keeping it all original, you can bypass the connector assembly. http://www.madelectrical.com/electricaltech/amp-gauges2.shtml shows one method. FWIW, when equipped with a 100A alternator, larger wires were fed thru the firewall using separate individual connections.
If your connections on the firewall are OK, pull the instrument cluster and check the connections on the ammeter itself. These are ring terminals, held onto the ammeter with nuts. I've seen them loosen and cause a similar current limiting (and heating/melting) issue.
Bryan
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Try to find a wiring diagram. Starting in 1980 the charging current did not go through tha ammeter. The ammeter was connected across a portion of the wire between the alternator and the battery with a couple of about 20 gauge wires, effectively using the feed wire as a shunt for the ammeter. An open ammeter will make no difference. A more likely area to look at is either of the two heavy plug type connectors in the 6 ga wire between the alternator and the battery or the 14/12 ga fuse link in the same wire.
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The easiest way to check this would be to measure voltage at the alternators output terminal with the engine not running. If you get no voltage reading then you have a failed connection or fusible link on the output side. If you do get battery voltage, I would then put some type of load on that connection (like a headlight) and measure it again. If you still get battery voltage or within 1/2 a volt of it, then the connection between the battery and the alternator output is fine and I would start looking at the regulator and field wiring as your most likely cause of your problems.
--
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ammeter
I stand corrected... if the SHUNT is open, you'll get no charging current.
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