Dash light question

Dave621955 · Oct 11, 2014

I've been sorting out 50 years of pieced together wiring and have run into a head scratcher. Somewhere along the line dad added a ammeter to the tractor along with the red dash light that was there and had it wired sort of strange "I think". Anyway I've searched for wiring diagrams that have both the ammeter and red dash light for a to-20 and can't find one so I took a shot in the dark and came up with this. I ran a lead from the starting motor switch to the + side of a new ammeter (old one was rusted out) and from the - side to the battery terminal of the voltage regulator. For the red dash light I ran the leads as shown in the I & T shop service manual, from the generator terminal of the voltage regulator through the dash light to the ignition switch to the coil. Now if my memory serves me the light comes on when you turn the ignition switch on or when it's not charging and goes out when the system is charging. So when the rpm's increase a bit the light goes out - right? Well mine doesn't go out?? What am I missing?

Thanks Dave

Steve@Advance · Oct 11, 2014

Sounds like it's wired properly.

Have you determined if it is actually charging? Best check it with a volt meter instead of trusting the amp meter.

If it is charging, likely the problem in the regulator.

Did you polarize the regulator?

Dave621955 · Oct 12, 2014

Thanks for the reminder Steve, I forgot to polarize it - the mind is the second thing to go... Have something else interesting. I've never checked the voltage during operation but did today after reading a post. Before starting the battery reads 6.3 volts approximately, after startup when the light goes out it reads a VERY unsteady from 6.5 to 12.5 give or take. is this normal?

Thanks Dave

Steve@Advance · Oct 12, 2014

No, the fluctuating voltage is not normal.

Is the regulator base properly grounded?

If grounding doesn't correct it take a look inside. It should be clean and dust free. Look at the contacts for burning and pitting. If everything looks good try cleaning the contacts with contact cleaner and blot them with paper. Some swear by filing or sanding, I personally don't like to but really nothing to loose if it gets it to work.

There are adjustment procedures. Look under the "articles" section, there are good step by step instructions there.

One other thought, are you using a digital volt meter? Try testing with an analog. Sometimes digitals get confused with minor fluctuations, they will throw bad readings.

Dash light question

Dave621955

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Steve@Advance

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Dave621955

New User

Steve@Advance

Well-known Member

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