Voltage Drop Heater - strange power readings

[EdRedBird]

So I am suffering drop on my chinese heater.
I have shortened the power + and - in to just before the harness and replaced the standard cable to 10AWG

Now with the multimeter I get 12.6 at the battery... 12.6 at the end of my 10AWG ...and 12.6 at both sides of the connecting plug
BUT
At the top near the controller I have 3 thin wires in a plug and here 2 of the cables read about 5V (Well one of them is 5 the other 4.6/4.8) the third seems to be @common@
These values correspond to what I read on the connection plug where my power goes in ...tracing back ...

I really was hoping one of these would be nearer to what the display says ...which STILL has my 0.5 drop on standby...more when i start drawing current.
In that case I would have upgarded the cables to the controller....

The fact that both ends of the cable towards the controller read the same ...would imo mean there is no fault in that cable.

1) The fault is in the harness
2) The fault is in the controller

Any Ideas?

 

[AdrianChen]

Is that measured when the glow plug is running? with no current there shouldn't be any voltage drop anywhere. Not sure what the 3 thin wires are for though but Im sure someone will come along.....

 

[Raul]

Maybe the controller is fed by 5v from the pcb. Does it work, does it stat up?
Voltage drop is only showing under load. If no load, no drop.
When you press start, and the glow plug starts to heat, measure quickly the voltage at battery, then at the harness, where you joined the 10 awg.

 

[Two on Tour]

The three thin wires at the controller are normally a red, a black and a blue. The red and black are the power to the controller and the blue is the data line that sends instruction to the motherboard from the controller and receives the heaters information that is the displayed on the controller.

 

[Two on Tour]

Maybe the controller is fed by 5v from the pcb.

Yes the 5v is a feed to the controller from the heaters motherboard.

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[EdRedBird]

AdrianChen The contoller reads 12.1V when taking these readings.....
Raul Surely one of the 3 leads to the controller should get that 12.1 which is actually 12.6 or how else does the controller take its reading?
@twoontour are you saying i am trying to measur for the actual voltage(drop) at the wrong spot?

1: I have 12.6V Just before the start of the harness (2inch) on the 10 AWG
2: I have 12.6 at both sides of the harness plug on the red and black lead the 10AWG is connected to
3: I do not get this 12.6 on any of the other wires controller or pump
4: The controller reads/detects ...in off mode... already 0.5V lower than the input, if the glowplu starts heating it drops well below 12.... thats fine on day one but after being parked for a bit and my input power droping to 12.4...12.2 ..that is an issue. I assume the controller calls the shot for an E00

I could considder replacing all plugs/connectors with spades and or IF this is some weird way on the motherboard of the heater?? Bring in an additional power line directly to the motherboard