New front harness, flat batteries

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Re: New front harness, flat batteries

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Re: New front harness, flat batteries

Postby TraceL » July 12th, 2018, 4:49 pm

I just want to make sure I do it correctly. Which side of the starter switch should that “ground” cable I disconnected from the starter switch be hooked too? It was hooked up to the lead on the right if you are looking at the front on the switch. The side that goes to the batteries.
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Re: New front harness, flat batteries

Postby rickf » July 12th, 2018, 5:08 pm

There should be no ground hooked to the starter switch?! Are you talking about the starter switch on the floor? You will have the main positive wire from the battery going to one side and the other side will have the other large wire going to the starter. On the same side as the main battery wire you will have a smaller wire which is your connection for all of the power for the vehicle. You should also have a connection from the alternator going to the side with the main battery wire connection. They should be the only connections on the starter switch.
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1984 M1008
1967 M416
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12/1952 M100- Departed
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Re: New front harness, flat batteries

Postby TraceL » July 12th, 2018, 5:30 pm

I only had the cable that comes out of the harness down by the highbeam switch connected to the main battery side. There is no other wire connected to the switch, other then the one from the batteries, and the one to the starter.
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Re: New front harness, flat batteries

Postby rickf » July 12th, 2018, 8:06 pm

The small wire that is hooked to the battery side of the switch should have a tag on it and be number 5.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone
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Re: New front harness, flat batteries

Postby Fil Bonica » July 13th, 2018, 9:06 am

If you refer to the A2 wiring diagram you will see there are two wires marked 6.
One comes from the battery.
That is the hot wire .
Attached to that wire should the numbet 5.
The other side of the switch should have the other wire marked 6.
It should go to the starter terminal.
If you have an electrical fuel pump then there could be a small wire going to the starter side of the switch.
It would supply power to the pump on starting .
There is no ground to the starter switch as Rick says.
A failure of the switch would typically be leakage current through a carbon track to ground.
Connecting ground to the switch could provide some exciting results!
Hope this helps.
I will be coming to Weare .
If you need some help I can bring tools with me.

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Re: New front harness, flat batteries

Postby rickf » July 13th, 2018, 10:47 am

The A1 fuel pump/starter wire is included in the #77 circuit going through the safety switch on the oil filter adapter. There should be no pump wire at the starter switch. The wire you are thinking of is #77B and is attached at the starter.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone
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Re: New front harness, flat batteries

Postby TraceL » July 13th, 2018, 3:07 pm

Yes, it has the #5 tag on that wire going to the battery side of the switch. I’m wondering if the starter switch is the problem, or it’s something further down the line. You did mention that the harness gets its power from that switch. So if it’s disconnected, it’s killing power to everything plugged into the harness correct? Those starter switches seem to be few and far between online. And at a ridiculous price. I will probably replace it, just to eliminate it as a suspect. But I’m guessing there is another issue. Especially since I get sparks and a reaction on two gauges when I hook the batteries up and the (new) on/off switch is in the off position. I’m still trying to see if it is the gauges are making the clicking sound, or if it is a relay. Electrical gremlins are so much fun.
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Re: New front harness, flat batteries

Postby Hambone » July 13th, 2018, 3:33 pm

If you disconnect #5 and still have a draw, them I would look at the switch, if you disconnect #5 and the draw goes away ,then back to the process of elimination.
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Re: New front harness, flat batteries

Postby TraceL » July 13th, 2018, 3:47 pm

Disconnecting #5 eliminates the draw. Disconnecting it actually turns a 26 volt reading, into. -3 reading.
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Re: New front harness, flat batteries

Postby rickf » July 13th, 2018, 5:14 pm

Then your draw is in the system somewhere, You just need to continue to disconnect things until you find the problem. Now do you have the ignition switch disconnected? If you have that switch disconnected and you are still getting power to the system we need to find out how it is bypassing the switch. The ignition and headlight switches are the only things that have power before the system and if they are both disconnected then technically there is no connection. With the possible exception of the voltage regulator. If you have the A1 25 amp system then disconnect the plug from the main harness to the regulator on the firewall, if you have the A2 60 amp system then disconnect the #5 wire at the alternator but be sure to wrap tape around it so it does not short out on anything. With all of that stuff disconnected if you still have action at the gauges then you are going to have an internal wiring issue.
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1984 M1008
1967 M416
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12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone
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Re: New front harness, flat batteries

Postby TraceL » July 14th, 2018, 11:49 am

I’m not sure if this will help diagnose the problem or not. When it’s running, the voltage gauge bounces back and fourth in the green. It’s a steady movement back and fourth that seems to have a corespondening noise. It sounds like a squeak. The noise goes with the needle on the gauge. Once you turn on the lights the sound gets louder and the needle on the gauge moves back and fourth faster. The needle doesn’t just bounce all over. It’s almost like a tick. Very constant.
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Re: New front harness, flat batteries

Postby Hambone » July 14th, 2018, 12:15 pm

Completely disconnect the alternator and see if you still have a draw.
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Re: New front harness, flat batteries

Postby Fil Bonica » July 14th, 2018, 12:48 pm

A test.
Measure voltage to ground with engine off.
Start engine and see if you can duplicate the varying voltage as seen on the battery gauge.
Typcally the voltage will rise by some amount and then stabilize.
If it contines to vary and bounce all over the place you could have a bad regulator in the alternator.
By the way Dont ever run the alternator without a load.
If you do the voltage can surge and destroy itself.
Hope this helps.

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Re: New front harness, flat batteries

Postby rickf » July 14th, 2018, 4:46 pm

Ok, I am going to back out of this one since I am telling him to disconnect things in order and try to narrow it down but others are saying to run it but do not run it without hooking things up. This is just going to confuse him even more. And the squeak is probably the belts slipping.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone
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Re: New front harness, flat batteries

Postby TraceL » July 14th, 2018, 7:52 pm

I’ll admit, I am thoroughly confused. I went through and disconnected the entire harness. I am going to reinstall it, checking for the draw after each system is hooked up. I’m fairly convinced that the harness itself has an issue. It was NOS, but I’m sure there are cheap knockoffs out there. Is there a list of what number wires go to which connections? I was hoping to find a step by step installation instruction. I am 95% sure it was installed correctly but obviously something is amiss.
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