Not charging

Tim23

Member
Side mount 8n, 12v, gm single wire altenator.
I got new gauges, and after putting on the ammeter my alt no longer charges. Replaced alt, still no charge. Dont wanna sound like a parts changer, but after triple checking the wiring i figured it had just gone bad. I have a trailer light wired through the ignition that goes off when alt charges, always worked before, stays on all the time now. Ammeter shows 0. This is the diagram i used. http://www.myfordtractors.com/12volt04.shtml
 
Check the voltage at the alternator's output stud before and after startup, preferably with an analog voltmeter, as the electrical "noise" from these old beasts can give a digital meter fits.

Then, post back.
 
I can tell you right now your wireing is in error if the ammeter reads 0. even with no charge.. it should read negative when running.

unless you have a compound error with 2 bad alts and a non open but non functional ammeter.


do the 'dummy' test.

cut all the ignition and charge wires off the tractor.

run a wire from charge stud to ammeter, from ammeter to bat hot, run another wire from alt side of ammeter to key, from key to coil ( thru resistor if using 6v coil ).

You now have the basice net charge wiring the tractor should have, key on, points closed.. ammeter should show 3ish amp drain. running, should show charge.

volt meter test across well charged battery before start, about 12.6, after start and revving up to ensure excited, and at about 600 rpm ( over 400 anyway ).. bat reading should be a minimum of 13.8 and a max of 15.5, but really around 14.4 or so.. all depends on the reg module used.

post back
 
Do you have an ammeter or a volt meter?
If 0 is in center it's an ammeter, if 0 is at left it is a volt meter. Volt meter wired like an ammeter will not pass current.

Did the alternator work previously or is this a new conversion? Charge light wires between output of the ignition switch and #1 pin on Delco alternator. It will not work if you have only the big wire coming from the alternator.
 
Ok, so i know my multimeter is a little( a lot) off, but i got 30v hot to grd from batt. 30v alt stud to grd, tractor off, on, running doesnt matter.
 
It is an ammeter. The conversion is not new. Everything worked before the ammeter. The light showing my alt is working comes on with the ignition and goes off when the rpms get up high enough. At least it did work that way, now the light stays on all the time. I will check the wiring again when i get a chance, might b this weekend.
 
(quoted from post at 13:42:26 06/19/14) I can tell you right now your wireing is in error if the ammeter reads 0. even with no charge.. it should read negative when running.

unless you have a compound error with 2 bad alts and a non open but non functional ammeter.


do the 'dummy' test.

cut all the ignition and charge wires off the tractor.

run a wire from charge stud to ammeter, from ammeter to bat hot, run another wire from alt side of ammeter to key, from key to coil ( thru resistor if using 6v coil ).

You now have the basice net charge wiring the tractor should have, key on, points closed.. ammeter should show 3ish amp drain. running, should show charge.

volt meter test across well charged battery before start, about 12.6, after start and revving up to ensure excited, and at about 600 rpm ( over 400 anyway ).. bat reading should be a minimum of 13.8 and a max of 15.5, but really around 14.4 or so.. all depends on the reg module used.

post back

I rechecked my wiring again and found nothing wrong. Ok, so i take everything loose and do the dummy test. Wired exactly as said points closed the ammeter does not move when the switch is turned on. It twitches right as the switch is thrown, but the needle stays on zero. I hook up the starter and start it up, no change with tractor running over 1000rpm. Take bat wire loose while running dies immediatly. 😕
 
Thankyou to everyone who replied to my post. SG u were right, my wiring was at fault. I had everything wired up right but while trying to make everything look a little better i unintentionally grounded the circuit going to my idiot light on my alternator. I was at work one night and it just hit me what i had done. Im still not sure about the ammeter, it shows no discharge ever, and pegs out at 3/4 throttle. Thanks again, i wouldnt b able to keep this tractor running without the help of everyone here.
 

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