My Tractor Forum banner

1976 ST12 (917.25930) decent wiring diagram?

8663 Views 7 Replies 3 Participants Last post by  Subbie
Hi,
Purchased a ST 12 locally and the owner had removed the complete wiring harness. He thought there was a bad connection on one of the wires? The wiring diagram on the underside of the hood does not have a color code. This is unusual to me as any equipment:banghead3 diagram I have encountered had a color code. The wires can be traced individually, but it is a pain. Is this true of the ST models? Anyone have a factory colored coded one for this model?
Dick (MI>CT)
1 - 8 of 8 Posts
Hi,
Found a similar ST model wiring diagram, The switch contacts are not marked with the single letter G, M etc. Will have to trace from the switch contacts via the harness to determine the wire function and label accordingly, one color is different. So it shouldn't be to big a task.
Dick
Here's a couple of places you can buy a copy of the manual from.

http://sears.pammar.net/manuals.html

http://searsgardentractors.com/manuals.htm

A copy of the parts data from Sears is posted also.

http://www.searspartsdirect.com/par.../00010189/00004?blt=06&prst=0&shdMod=91725930

Since I don't have a copy of the wiring diagram I will only be able to give you a little help towards wiring your tractor. You will need to take down the model number off of your engine. These days it is sometimes difficult to get accurate information because some people have swapped parts around to the point where model numbers may or may not help. The main thing to do is determine how many amps your tractor engine charging system has. Then you can lay out the parts for the electrical system and wire it up. The data from Sears says you have a 15 Amp and a 30 Amp fuse in the harness. The 30 Amp fuse runs to the starting circuit, and the 15 Amp runs to the light circuit.

Here's a universal wiring harness you might want to try. You might want to buy a couple of them so you will have enough wire if needed. Be sure to check your ignition switch to make sure it has five wire posts. The OEM switch has five posts so all you have to do is make sure of what you have.

http://www.ebay.com/itm/Stens-430-2...185?pt=LH_DefaultDomain_0&hash=item1e69dce939

http://www.jackssmallengines.com/Parts-Lookup/430538/56896/pd

Data for ignition switches follows.

http://www.jackssmallengines.com/rep_switches.cfm

Keep in mind I am going at it without really knowing what you have so don't etch it in stone. Just use it as reference material in helping you figure it out.

Attachments

See less See more
Hi,
Thank you for the information, I appreciate the time and effort. Good idea about the engine #, I will check it out. There are 2 fused wires and they were still attached to their components. Have it mostly figured out. Need to check the switch, but I think it is OK.
Dick
Okay, the engine model number and some photos would be a big help towards understanding what you have. I don't think they had any color coded wiring diagrams but some of the other members here can get pretty creative with MS Paint.
The earlier ST12's apparently had a color coded wiring diagram,I have found one. Which simplified things somewhat, but the switch is not marked. One good thing the owner removed the harness in one piece rather like a dissection?
At present I am selling off my old Ford part cars, which will give time to get back to my tractors. Have to get it going for snow plowing.
Thanks,
Dick
See less See more
Hope this helps:

I had to redo the wiring on my SS12 this summer. Not sure if your tractor has a starter/generator, but mine did. I replaced the ignition switch with a cheap automotive style one from tractor supply. I added a relay to shut the tractor off due to the type of switch. When the switch is off, the relay gets no power, and closes its contacts. The closed relay contacts connect the tractor ignition to ground as the original switch did. With the ignition on, the relay gets power, and the contacts do not touch. I added a dummy light to the normally open contact and common terminal to be able to verify that the relay was on and working.

Hope this all makes sense, if not I can try to explain it better. BTW, the PO had installed a starter solenoid, so that is why it is in the diagram.

See less See more
Thank you, clever system and the artwork is beautiful!
Dick
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top