The Ford Barn

tribouboys · 09-26-2021, 12:31 PM

So I needed to replace my ignition switch and in the process I discovered the wires on the back of the amp meter were in the wrong spot. I've wired it according the the Les Andrews book verified again and again the wires to the amp meter and terminal box are in the correct spot. When I start the car and it is at idle amp meter indicates slight discharge. Rev the motor up and more discharge.

Yellow/black charge side of amp meter to driver side of terminal box.

Yellow to discharge side of Amp meter to pass side of terminal box.

Terminal box to Generator harness is correct and my car has had all new wiring for years.

Prior to the ignition switch replacement yellow /black wire was on the discharge side of the amp meter and yellow on the charge side. wired like this there was no indication of a charging problem.
When I was replacing my switch I dug out the book just to verify the wires were in the correct spot and that's when I discovered the mix up at the amp meter.

Thank you in advance for pointing me in the right direction.

Mike Peters · 09-26-2021, 12:36 PM

When that happens to me, I reverse the ammeter wires, and then it works normally.

Patrick L. · 09-26-2021, 01:01 PM

What Mike says.

bbrocksr · 09-26-2021, 01:58 PM

Put them back the way they were.
Bill

midgetracer · 09-26-2021, 03:10 PM

Switch them as Mike says.

MAG · 09-26-2021, 03:23 PM

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Ford Script on face of ammeter?

rotorwrench · 09-27-2021, 09:50 AM

A long as a person can use a multi-meter to verify the generator output then a person can justify swapping the leads. Ammeters of the type used on the model A cars have a polarity to them. This is why many different type ammeters have no markings on the terminals. Current reproduction ammeters are likely not checked for polarity at manufacture. The OEM parts were.

tribouboys · 09-27-2021, 11:49 AM

Thank you all. I think my confusion occurred because I was not sure which amp meter post was charge /discharge. There are some nice pictures in previous thread of wiring and instrument panel.

KGBnut · 09-28-2021, 01:32 PM

Your car is not negative ground, is it?

Badpuppy · 09-29-2021, 08:58 AM

Check your battery ground connection. If it's to the negative post, then the ammeter will be reversed, as well as the coil.

09-26-2021, 12:31 PM	#1
tribouboys Senior Member Join Date: Aug 2010 Posts: 111	Wiring & Discharge So I needed to replace my ignition switch and in the process I discovered the wires on the back of the amp meter were in the wrong spot. I've wired it according the the Les Andrews book verified again and again the wires to the amp meter and terminal box are in the correct spot. When I start the car and it is at idle amp meter indicates slight discharge. Rev the motor up and more discharge. Yellow/black charge side of amp meter to driver side of terminal box. Yellow to discharge side of Amp meter to pass side of terminal box. Terminal box to Generator harness is correct and my car has had all new wiring for years. Prior to the ignition switch replacement yellow /black wire was on the discharge side of the amp meter and yellow on the charge side. wired like this there was no indication of a charging problem. When I was replacing my switch I dug out the book just to verify the wires were in the correct spot and that's when I discovered the mix up at the amp meter. Thank you in advance for pointing me in the right direction.

09-26-2021, 12:36 PM	#2
Mike Peters Senior Member Join Date: Aug 2012 Location: South East Wisconsin Posts: 1,279	Re: Wiring & Discharge When that happens to me, I reverse the ammeter wires, and then it works normally.

09-26-2021, 01:01 PM	#3
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Wiring & Discharge What Mike says.

09-26-2021, 01:58 PM	#4
bbrocksr Senior Member Join Date: May 2010 Location: Yakima Washington Posts: 913	Re: Wiring & Discharge Put them back the way they were. Bill

09-26-2021, 03:10 PM	#5
midgetracer Senior Member Join Date: May 2010 Location: Bismarck ND Posts: 1,189	Re: Wiring & Discharge Switch them as Mike says.

09-26-2021, 03:23 PM	#6
MAG Senior Member Join Date: May 2010 Location: Austin, Texas Posts: 925	Re: Wiring & Discharge Sponsored Links (Register now to hide all advertisements) Ford Script on face of ammeter? __________________ I noticed the harder I work the luckier I get!

09-27-2021, 09:50 AM	#7
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,422	Re: Wiring & Discharge A long as a person can use a multi-meter to verify the generator output then a person can justify swapping the leads. Ammeters of the type used on the model A cars have a polarity to them. This is why many different type ammeters have no markings on the terminals. Current reproduction ammeters are likely not checked for polarity at manufacture. The OEM parts were.

09-27-2021, 11:49 AM	#8
tribouboys Senior Member Join Date: Aug 2010 Posts: 111	Re: Wiring & Discharge Thank you all. I think my confusion occurred because I was not sure which amp meter post was charge /discharge. There are some nice pictures in previous thread of wiring and instrument panel.

09-28-2021, 01:32 PM	#9
KGBnut Senior Member Join Date: Jul 2011 Location: Southwestern Connecticut Posts: 931	Re: Wiring & Discharge Your car is not negative ground, is it? __________________ Style beats speed any day, and with a lot fewer tickets.

09-29-2021, 08:58 AM	#10
Badpuppy Senior Member Join Date: Dec 2017 Location: Guthrie, OK Posts: 1,144	Re: Wiring & Discharge Check your battery ground connection. If it's to the negative post, then the ammeter will be reversed, as well as the coil.