M931A2 battery wiring

[MAdams]

I checked the TM's but I don't have the wire # because the metal tag is missing. There are three wires I am trying to figure out where they go.
#1 has the metal tag and it says GND A. Obviously goes to the ground post on the battery.
#2 is a thin gauge wire
#3 is a heavy gauge wire

Wanting to know which one goes to the 12v side of the battery and which goes to the 24v side. Or which is wire 569a and wire 6

 

[Jericho]

Look in the 900 series manual in the T.M./T.O. section here on the site, the complete wiring diagram is in the appendix of the shop manual , volumes number 1 thru 5 , while your there download the T.O.s , they are free and a life saver ! read them cover to cover !

 

[therooster2001]

The TM doesn't seem to differentiate on gauge that I can find, so no help there.



I have a 2 batt config (old pict)



and it appears that the thicker gauge is the 12v and thinner is the 24v, however, if I were you I would trace them out, who know what happened to that truck before you got it.

Not near the truck so can't verify the tags..

 

[74M35A2]

Ground of one battery is not the same as ground of the other battery, just FYI. Ground of one will be +12v, and ground of the other will be actual ground. Maybe you knew this, but if not....

One smaller wire is the 12v feed to the heater blower "Low" speed fan setting. You can figure this out if your blower fan Does not run on "Low".

A few others may be the solar chargers if you have them? The P2P software download is useful. I can look up your posted wire number once I crawl out of bed.

 

[Jericho]

I think 74M is correct, just look for wire tags, if they font have any it could be owner installed stuff, I have REMOVED tons of it from my M 93A2 Iam headed out to the yard soon Ill look at mine , albeit a four battery set up, Still basic ly the same just in Parallel ( 12v to 12v , then series ,in twos then 24v , yours is in series if your only running 2 batteries neg to pos , 12v then series 24v

 

[simp5782]

I think 74M is correct, just look for wire tags, if they font have any it could be owner installed stuff, I have REMOVED tons of it from my M 93A2 Iam headed out to the yard soon Ill look at mine , albeit a four battery set up, Still basic ly the same just in Parallel ( 12v to 12v , then series ,in twos then 24v , yours is in series if your only running 2 batteries neg to pos , 12v then series 24v

He said his tags are missing. Small wire is 12v other. Bigger is the 24

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[therooster2001]

He said his tags are missing. Small wire is 12v other. Bigger is the 24
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Simp, you sure? I don't have my truck near and can't verify tags, so could be barking up the wrong tree, and unless I misunderstood my 2 battery config, the thick wire in my config (pict above) should be the blower, which is on my 2nd battery 12v positive post, that should be 569, so thicker wire would be 12v. 6B should go to 24v Positive and GND A should got to 24v ground. Right?

OP could still have different wiring and since no tags, trace might be necessary. OR it's me and I'm backwards.

 

[simp5782]

I have seen them different ways. My M934A1he wires are identical sizes know if you have the small wire to the main hot post you have full blower power with the switch towards the drivers side. Big wire to the positive on the Negative battery the blower motor barely runs with the switch turned to the passengers side. Put it to the hot post with the switch the same way it goes to full blast. I only have 1 truck here and its the 934. Wires in it are the same size plus its 4 extra wires.


I never use low on the blower. It does nothing. I just pull the fresh air and def handles out and heat rod in when i want less heat
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[therooster2001]

I never use low on the blower. It does nothing. I just pull the fresh air and def handles out and heat rod in when i want less heat

Well that's one way, ditch the 569.

Madams, I would check the wiring back to the 12v blower switch. Bust out the multimeter and know for sure, shorting things out is not fun.

 

[Jbulach]

My 91 A2 has small "GND A" to ground. Large "569" to 12 volt. Small "6B" to 12 volt. No other wires in battery box..

 

[simp5782]

https://youtu.be/-OWa4pB2zUQ

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[MAdams]

Thank you guys for the help. The thick wire ended up being the 12v 569 slow blower motor wire.

I still don't know what the thin wire does. I assume its 6B but I can't figure out what it goes to. Same with GND A, nothing doesn't work without it.