Jump to content

Need help on a 59 B 12/24 parallel series switch

Recommended Posts

Hi All, 

I am hoping someone has an idea here as I am a bit confused. At some time someone cut the batteries off the truck (4 6volts) and I am adding 2 12v. 

Here is a diagram of how it is currently wired. I know this is wrong because there are currently 3 neg terminal ends and one positive that goes straight to the starter. I have looked that how other trucks are wired and also looked up a few diagrams but that seem to have different answers to each. First the Owner swears this is a negative ground but I am not so sure. What does appear to be happening is they look to have set it up on 12v and were using jumper cables when starting. 

If anyone has some clarity I would be appreciative. I think it is supposed to be 


f1 - 2+

f2 - 1+

f3 - ST2 

f4 - 2-

ST1 - 1- 

But I am not certain as the diagrams conflict. What I am certain of is that when we hook it as it is, it tries to melt the last battery terminal we hook up. 

I get how series parallel works.   with one set connected neg to pos and the left over positive going to the truck and left over neg going to ground giving 24v

What I am not certain is how the switch is making the connection. 

It would seem to me it makes it across f1 to f3 but I need to learn a bit more apparently cause I am not certain on this. 

When I run 12v from a hot to the small post on the rear drivers side of the switch I get a "click" but that does not mean the switch has not failed and hence the goofy readings we get on the OHM meter. 





Link to comment
Share on other sites

When you hook the batteries up does the amp gauge show whether its charging or discharging 

If it shows its charging and the motor isnt running it would mean the polarity is back to front and if you have it hooked up for negitve ground its postive ground



Link to comment
Share on other sites

This may be what you have already seen. The old voltage regulators were either negative or positive ground, but the more modern ones can be used with either.

If your series/ parallel switch has through bolts open it up and repair the burnt contacts.

There are two sets of contacts within the S/ P switch. 


series parallel switch wiring.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...