Farm Equipment - 7020 atlernator light

Print Page | Close Window

7020 atlernator light

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=199265
Printed Date: 24 Sep 2024 at 5:27am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: 7020 atlernator light

Posted By: CDN 400
Subject: 7020 atlernator light
Date Posted: 15 Jan 2024 at 4:46pm

Going through my new to me 7020 and can't get the alternator light to work. With the key on and even with the alternator unplugged I have power on both sides of the light socket. Where do I start looking. I'm fairly handy but I hate electrical problems.

Replies:

Posted By: steve(ill)
Date Posted: 15 Jan 2024 at 4:52pm

power normally comes from the key switch to the light... then OUT to the alternator and is grounded when the motor is off ( alternator not working)... when the motor starts up, the alternator puts out voltage to PUSH BACK to the bulb and balances out the power from the switch so the light has equal voltage on both sides and does not light..

The light bulb wires should be HOT coming from the switch.. and if you check the other wire to the alternator, it should show grounded.( if the light bulb is removed, or wires pulled off the socket).... Start the motor and it should show VOLTS toward the light.

-------------
Like them all, but love the "B"s.

Posted By: jaybmiller
Date Posted: 15 Jan 2024 at 5:00pm

With it disconnected from the alternator, you will have +12 on both sides of the light bulb and the light will be off. That is normal. Think of the filament of the light is just a 'fancy' piece of wire all coiled up in a glass bulb, it's no different than measuring 12 volts on a long piece of wire ,say from ignition switch to headlights.

-------------
3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)

Never burn your bridges, unless you can walk on water

Posted By: CDN 400
Date Posted: 15 Jan 2024 at 5:22pm

I think I get what your saying and I think the ground is the problem, with the alt plugged in and the key on no light pull the bulb and power on both sides of the socket.

Posted By: jaybmiller
Date Posted: 15 Jan 2024 at 5:39pm

with alt unplugged, if you ground the pin on the lamp socket that goes to alt, light should come on.

if that's true and NOT come on when connected to alt, 'bad alternator'.....sorry.

-------------
3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)

Never burn your bridges, unless you can walk on water

Posted By: CDN 400
Date Posted: 15 Jan 2024 at 5:48pm

You can't do much with the socket all the warning lights are in a circuit board. The circuit board looks good not burnt.

Posted By: jaybmiller
Date Posted: 15 Jan 2024 at 5:52pm

OK, try at the alternator connector ?

course it'd help to know what alternator.

some are 2 prongs, some 4, some 5....

-------------
3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)

Never burn your bridges, unless you can walk on water