Amp gauge

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Model T Ford Forum: Forum 2012: Amp gauge
Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Sunday, September 02, 2012 - 06:41 pm:

Why is it my amp gauge worked fine till I repaired my switch and reinstalled everything?Now it wont show discharge when the lights are turned on,but it will show a charge sometimes?
These amp guages seem so wimpy.What fails about them? I have several,the movements are free,they shake.They show continuty.So what fails about them? I have a original large gauge I would like to use but again,it shakes,it shows continuty,and nothing appears burnt.
What gives?


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, September 02, 2012 - 07:47 pm:

Do you have a wiring error? Original Ammeters were only 5% accurate and some of them are so wiggly that if you hit a bump the thing may wiggle till you get home :-) If you have a six volt system and your headlights light up when you turn the lights on but your ammeter does not show a discharge somewhere between 8 and 12 amps then you might have something not connected right. There are 5 wires that need to be connected correctly for charging to occur and all but one of them must also be correct for discharge to occur at the ammeter. All 5 are heavy #12 Gauge. Start at the battery side of the starter foot switch and note a solid yellow heavy wire connected there. That is the main supply to the whole car. That heavy solid yellow wire goes to terminal 3 on the barrier strip. The barrier strip is numbered left to right as you face it. The path continues with a #12 solid yellow wire going from Barrier strip #3 to one side of the ammeter. The path continues with a yel/black #12 wire from the remaining side of the ammeter to the BAT terminal on the ignition switch. The path further continues with a #12 yel/black wire from the BAT terminal of the ignition switch to Barrier Terminal #1. The next path is a #12 yel/black wire from Battier Strip terminal #1 to the cutout screw terminal located on the cutout atop the generator. Those 5 wires must be as stated for you to have any hope of seeing any charging from the generator to the battery. If you rebuilt your ignition/light switch then you should see the lights turn on when you flip the light switch lever from off to DIM or BRIGHT. The power for the lights is picked up via the light switch which is part of the path just mentioned since the light switch connects the BAT terminal on the ignition switch to the headlights and tail light.

What year is your T? The 19-25 T's used a larger ammeter and those generally are not as bad as the 26/27 ammeters. Some of the larger '19/'25 ammeters with the very long needle sourcing out of the very bottom of the meter face tend to be the "bounciest" of the bunch but the repro small units for 26/27 can be off a ways and may or may not bounce too.

My repro large meter is not known to bounce but it is a bit more money. While you might like it for not bouncing, I am wondering if you don't have a wiring error or something. If you are not seeing any movement at all on the ammeter with lights on then I suspect you have a wiring issue.

Hope this helps.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, September 02, 2012 - 08:32 pm:

In addition to John's comments here are a couple very helpful tips.
There are many incorrect Model T wiring diagrams floating around in various publications. Here is one that is correct in all regards. When I help folks I refuse to use any other wiring diagram and ask them to do so too so we have a common frame of reference.
1
I work on many Model T's where the charging system is not working. The natural inclination is to suspect the generator or cutout, but I learned long ago that is not always the case. I annoys many people I work with (they believe their car could not possibly be wired wrong), but I always insist upon conducting the following two simple check to satisfy myself the car is wired correctly and the five wires of the charging and discharging circuits John mentioned above are properly placed. You would be surprised the number of times the car is simply wired incorrectly.
Here are the two tests.
Check one: With the engine not running simply turn on the head lamp switch and note the ammeter deflection. If it does not show a discharge the car is wired incorrectly.
Check two: With the engine not running remove the yellow wire to the cutout (remember this wire is directly connected to the battery), remove the cutout and momentarily touch the yellow wire to the generator output terminal noting the ammeter deflection. If the ammeter does not show a discharge of about 6 amps the car is not wired correctly.
If either of these two tests do not have the correct result follow the five wires.
These two simple tests will tell if the charging and load circuits are working correctly and you can continue to diagnose the generator, cutout or ammeter troubles.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Sunday, September 02, 2012 - 11:02 pm:

Thank you folks.
I appreciate the help and the wireing diagram.I will have to put it back in the shop and check this stuff.It just stumps me I never pulled but 2 wires off and that was the 2 going to the meter from the meter.It worked fine before the switch was removed and repaired.I did not remove wires from the switch back,just held it and cleaned it and then laid it aside sorda till I got the other parts ready.It is when I put it all back together,and hooked the 2 wires back to the meter that I noticed it quit.It has the black switch plate for the 17-25 T .I have a small meter in it with a adaptor plate.

Ron Check 1 is the test I did and noticed the fault.
The meter did deflect before because if I had the lights on while driveing and cut the engine off,I would notice the deflection and remember to turn them off.
I dont have the correct color wires as I made my harness but I can follow that schematic and see what is going on.
The 1 thing I feel it could be is literaly a loose wire on the back of the switch.But I thought I tightened all that.But you never know.

Out of curiousness I used a small battery and a bulb and ran it thru the other meters I have.None showed a defection.Yet,the needle swings,and there is a circuit thru it.
I reckon maby I am just looseing my mojo with this stuff.Aint had much good luck with several things I have worked on lately.Maby it is just spreading over into my T hobby.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bede Cordes, New Zealand on Sunday, September 02, 2012 - 11:23 pm:

Mack, you could swap the wires on the two terminals of the ammeter and see if your meter needle swings the other way when re-doing the tests you have already done, this will put your mind at rest that the meter is ok (ie: not sticking) and the fault most likely is in the wiring or elsewhere. Good luck, Bede.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Sunday, September 02, 2012 - 11:33 pm:

Just curious Ron; Where did that diagram come from? It seems to be inconsistent with Ford's own service diagrams as far as wire colors for several circuits across years. (19-25, 26-27)


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Monday, September 03, 2012 - 12:14 am:

Mack:

If you used a small bulb I would be rather surprised if you got much if any deflection on any ammeter since the meter needs 20 amps to go to full scale and small bulbs are typically near or less than 1 amp so only a half of a mark on the 20 amp scale. What bulb were you using for you ammeter test on the bench? When you said you used a small battery - if you are talking about a flashlight battery you won't get much if any deflection. - try a fully charged 6V battery and one of your headlight bulbs. Are the 5 charging path wires verified to be #12 since that is pretty heavy. None of your wiring should be solid conductor - use only stranded wire or you will have a lot of flakey connections from broken wires and loose terminals from the cars vibration.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Monday, September 03, 2012 - 12:39 am:

Well,to be honest it was a 9 volt transistor battery.Maby I need to try something heavyer.
I do know my wire is stranded that is related to the chargeing..I know there is a heavy wire comeing from the battery,and from the meter.
Fixen to hit the sack,past midnight.But I will git it back in the shop and see what is going on with this info.

I do know i used what wire I had at the time.I think green is what I used that is hooked to the amp gauge.It is heavy.At the time i wired it,in the late 90's,I was on a tight budget.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Monday, September 03, 2012 - 01:04 am:

Wire color doesn't matter but the paths I called out define 5 wires. ALL of them need to be #12 AWG stranded wire - there is not an accepted standard definition for "heavy". I am not suggesting you change all your wires but a simple comparison of the size as compared to a piece of #12 would tell you what you have. 9V battery is capable of about 1 amp max for a short time but I doubt you would see the slight deflection on a 20-0-20 meter and probably not much at all if you had a small bulb too. I think you may or may not have a problem with your wiring but your testing using the 9V battery and a bulb put you in pursuit of the elusive wild goose. Chased them myself a few times and unfortunately they are always in season.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Monday, September 03, 2012 - 07:56 am:

Ok,Wild geese,I cant stand chaseing them blasting things.
Thanks.Breakfast,and work on my shop air conditioner a little bit and then this.
My printer dont want to work with this computer.but I have a computer in the shop and will put this diagram on the screen and zoom in.People thought I was crazy when I got a older free computer,patched it up and put it in the shop.now projects like this are easyer.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd on Monday, September 03, 2012 - 11:28 am:

“I never pulled but 2 wires off and that was the 2 going to the meter from the meter”

“put it all back together,and hooked the 2 wires back to the meter”

Mack, these 2 lines in your post tell me that you disturbed something in the meter when you R&Rd the wires on it. It sounds like you twisted the studs slightly w/out realizing it and this affected the innards.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Monday, September 03, 2012 - 02:22 pm:

Oh Joy,I have learned alot in a little time.The movement that looked like it was chargeing,even with the meter unhooked, it would move over that far,about 8 amps at hi idle.So all this time i THOUGHT I was chargeing my battery,i may not have been.No output at generator.I tested this by useing a amp gauge from a old battery charger and a 6 volt bulb generator post,thru the bulb and gauge,then ground.Nothing..And I know I had that working at 1 point because Ron helped me out by email I think to set the generator amps.So Looks like I will be digging deeper into this than I expected.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Monday, September 03, 2012 - 05:00 pm:

Ken
I selected that wiring diagram because all the wires are shown physically correct which is a common problem. It is still my choice for troubleshooting Model T wiring problems.
I checked it against the original Ford wiring loom drawings. The wire gauges are correct for all wires. The headlamp circuit wires and timer wires basic colors are correct, but do not show the tracers. The tail lamp circuit wires color is wrong and should be black.
When troubleshooting an original Model T the wire colors are usually not discernible.
Newly made wire looms available today are a combination of wrong colors and wire gauges.
Ron the Coilman


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