Head Light Ground 1976 Square CIUB 12V

[Farmer Mike]

I am looking for the location of the "original" ground location for the front lights.

The wiring has been corrupted, broken, spliced and switch all unplugged and fuse wire broken but getting that all sorted.

I have confirmed that all the head and tail lamps work directly from a 12V source.

I understand the tail light has two positives from the light switch; one for the red lamp one for the bright lamp and share a common ground that is secured to the base of the lamp post.

The head lights are a bit more complicated.

They share a common 12V hot and ground wire that were cut around the radiator. Two wires to both with a rubber plug at the back that are then joined together to the wiring harness. I think the left feeds off the the right wires. That is where it ends.

Some where near the starter there are two cut wires in the wiring harness which I assume are for the head lights. I have not traced these back yet I assume one for low and one for bright to the switch.

Need help with:

1. What color are the hot wires from the switch to the head light everything is mostly yellow paint.

Low = ? color also links back to the resisted stub at the switch I presume
Bright = ? color
Ground = ? color

2. Where is the ground suppose to be for the wire to the headlights. I know basically the whole tractor is ground but wanted to route it correctly the first time.

I have an MGB which is surprisingly similar in wiring to the CUB there are wiring diagrams available the indicate routing and wire color. Does a wiring diagram exist for the CUB with colors detailed.

[tst]

this might help, I think the ground was at the dash panel mounting bolts, or at the alternator

[staninlowerAL]

Welcome to the Forum.

........Does a wiring diagram exist for the CUB with colors detailed.

Yes. One more post and you can access/download the manuals and diagrams from the Quick links folder at the top left corner of this page. Open the link and select pdf manuals, then search for the Cub folder and you should find most of the information that you are looking for. I recommend the Parts Manual like TC 37F which contains detailed drawings and parts info the wiring harness, routing and colors as well as just about anything else that you want to know that is Cub related. JMHO. Stan
BTW, 1976 was the first year of the INTERNATIONAL Longstripe Cub beginning with SN 248125. 12V system was introduced several years prior (I think 1967) and there were changes over the years. The changes are detailed in the manual that I referenced. Another good reference for changes is Raymond Durban's database file located in the first post of the Cub Forum.

[Jim Becker]

I believe the diagram tst posted is correct. You will probably find the connection diagrams in the latest Cub Parts Catalog to be helpful as well (in the PDF manuals). You are under a misconception that there are both dim and bright wires to the headlights. There is just a single power wire to the lights. Dm is accomplished by a dimming resistor at the switch. The 2-conductor plug at each light has one power lead and one ground lead. The rear light has a 3-conductor plug with leads for red, white, and ground. All 3 are in a harness that goes to the dash panel.

[CharlieK]

welcome

[Glen]

Hi,
Cubs were changed to 12 volts in mid 1964.
Cub serial number 248125 was made in mid 1975.
248125 and above have the Delco alternator, and the Zenith carburetor.

Below is the Cub operator's manual for Cubs serial number 248125 and above. It has lots of info, and shows some of the electrical system parts. There is a contents on page 2.
It shows some of the headlight wire routing on page 39.
While the hood is off is a good time to oil the fan hub, if you didn't.
It tells how on page 54.
I use a clean pump oil can to pump oil into the hub.
The hub uses light motor oil. Be careful to not lose the small gasket that should be on the oil filler screw, it could be stuck to the hub.
https://farmallcub.com/rudi_cub/www.cle ... index.html

I would check or change all the oils before using the Cub, if nobody has checked them lately.
I see you have your settings so people can't send you a Private Message. You get to the PM at the top of the page. I was going to send you one. If you want to change the setting, click on PM, then Board Preferences.

[Farmer Mike]

Thanks for the support.

I did trace a single wire with a female terminal in the dash into the wiring harness and out into a in a bundle of twisted and tape wires that diverged from the wiring harness near the alt. So I can assign that one as the headlight power supply. Plug it back to the correct male end of the resisted light switch terminal.

Figured out the Rear light pretty quickly once I figure there were only two going to the rear.

Two other wires in the bundle both trace back the the power side of the ignition switch. I am reviewing the provided diagram for their purpose. These share the common terminal with a thicker wire from the meter and possibly the supply wire going to the fuse.

Tricky thing to sort out is that there is only one wire at the key switch and two wires with continuity coming out of the harness along with the light wire. The Harness wrapping material is intact and unmolested between the dash and alternator, So probably not crossed wires.

More sleuthing tomorrow.

[tst]

The heavy wire goes from the stud on the alternator to the amp gauge

[Farmer Mike]

Diagram indicates Green to light fuse wire originates a (-) negative terminal of the meter. This does not make sense since it is a negative ground system.

?? Meter (-) -> Green wire -> Fuse - black Wire -> Light switch "BAT" then out to lights. I guess the two other wires in the bundle are ground that grounded in the key switch, thus the continuity of both wires with the key terminal. That would kill the lights when the key is off with no ground?

Is that correct?

[Farmer Mike]

SN 250681 - 1976

1. I think I sorted the PM issue

2. It is getting a full rest so It can go back to the field, all fluids and then some. Air filter , Fuel system, Oil, Trans. Hydraulic, Cooling, Final Drives, Zerks, steering box. Cap rotor and wires, has newer internals, Battery box lid and correct size battery and sort wiring.

I'll add the fan oil to the list.

About $500 in parts and materials so far.

Replacing all the hood bolts with all 1/2" stainless steel so its a one wrench task. Lube every thing I can.

Radiator and front tires look a bit dicey but not in the budget this season.