electrical issues

[dieselfreak93]

i have a 99 6.5 chevy 1 ton and there is a ground on the back of the intake manifold from the wiring harness that has 2 wires (one black, one tan) tied together with an ilet theyre only about 6 in long and when i test if with a multimeter it shows dead with key off and 11.38 with key on and i cant find a short anywhere! anyone heard of seen this before

 

[MrMarty51]

Try unhooking the brown wire and see what happens.
There should not be live voltage hooked to any ground.
Unless they changed color code, both wires at the back of the intake manifold on Mine 2000 K350 are black.
Look all around the harness near that location, see if there is a loose black wire.

 

[MrMarty51]

OH YEAH, pardon My bad manners.
Welcome to the truck stop DF.

 

[Big T]

Is this a 4wd?

 

[Will L.]

If there is something turned on and not working, and these are the ground wires for it- and the ground connection to the engine is bad, they will read voltage.

Have you removed and cleaned the connections?

Think of it like this power into the center pin of a
Light bulb resting on a wooden bench. The power will go through the lightbulb filament and will read power on the outside of the bulb that normally gets grounded.

If you post a pic we can tell better whats there

Also- what is going on with it? You just buy truck and checking things over, or all was fine then something quit working?

 

[RDasher]

Not sure if it helps, but for reference, on my 99 6.5L that ground has one tan, one black and one heavier gauge black connected to that eyelet. They all run from the harness, so I am not sure what they connect to.

 

[Big T]

Not sure if it helps, but for reference, on my 99 6.5L that ground has one tan, one black and one heavier gauge black connected to that eyelet. They all run from the harness, so I am not sure what they connect to.

If this is a 4wd and the brown from the plug behind the FFM, that brown comes from a sensor on the transfer case. It's what you tap into to convert from the thermal 4wd actuator to the electrical 4wd actuator.

 

[MrMarty51]

Get that brown wire out of the grounding circuit.

 

[Paveltolz]

Do they look like this minus the pine needles and oil?

 

[Paveltolz]

Both of those wires are at G104 (Ground) return to the ECM. Tan/White grounds the ECM so, removing it isn't the best idea for connectivity. Black and white, as you can see, hits a lot of items to include the ECM.
Two bolts forward on the intake manifold is G105. There's a plethora of components sharing that ground there on a solid black wire. If you're getting voltage at G104's wires and they're still attached to the intake, you may want to check for voltage at G105.
Hope the Schematics help. I've got too much stuff stacked on my 99 to get a picture of the two ground points.

 

[Paveltolz]

Found this one after edit time expired. Grounds at the ECM for G-104&5

 

[MrMarty51]

Get that brown wire out of the grounding circuit.

UHHHHHHhhhhh, dont unground that wire. LOL

 

[Chevyfan]

Can anyone tell me y my supply pump runs until I connect these 2 wires to a ground then injection pump plunger opens but supply pump shuts off wires r same as mentioned above blk/wht Brown wire

 

[MrMarty51]

Is that with the key in the on position ?
ECM turns on the lift pump for a few seconds when key is turned to run. If those wires are not grounded, it might not give the ECM the ability to turn off the LP.
I`m not exactly sure how it all functions so someone with more smarts than I will hopefully answer too.