In a message dated 98-09-08 12:52:51 EDT, dstauffa@csc.com writes:
> My question to the list is this:
> Is there a way I can test the ammeter and alternator to see if both
> are functioning properly?
> If both are OK, any idea why my ammeter shows only a discharge?
> Why my Ind light does not go on when I turn the ignition on?
Dave,
Two simple steps for checking the ammeter:
1) With the engine off, turn on the lights - you should see a discharge
reading.
2) With the engine running at 1500 rpm minimum, blow the horn - you should see
a charge reading. Yes, as odd as that sounds, the horn will show a charge
reading if the car is wired as it left the factory.
To test the alternator, run the engine at 1500 rpm or better, turn on your
high beams, heater motor, radio, etc, and measure the voltage at the battery.
it should be 14 - 15 volts.
To check the indicator light, remove the plug from the alternator, turn on the
key, and short the brown/yellow wire to ground (if you have three brown/yellow
wires, short any one of them - they are all connected together). If everything
is ok, the light should come on.
If it doesn't come on, you are not getting the "bootstrap" voltage to the
alternator to initiate the field current, and the alternator will not charge.
The other side of the light goes to terminal 5 of the ignition switch via a
white wire. Look for voltage on the white wire at the lamp.
If you don't have voltage, look for a break in the white wire. If you do, look
for a break in the brown/yellow wire from the lamp to the alternator.
If this doesn't help, let me know what you find and we'll take it from there.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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