After C5 Diag posted a video on voltage drop testing I wanted to check my own car regarding this issue
and did a votage drop test on both battery voltages (maxifuse 52 and 53 and the ignition switch feeded voltage fuse 5 (schematic below ) and also a voltage droptest on the G108.
Both maxi fuses turned out okay and a votage drop between terminal B and battery negative on 0.2 volt I think is fine.
On the ignition switch feeded voltage on A a total of appr. 0.9 voltage drop was measured.
When I checked it today I noticed a drop of 0.1vol between battery plus and maxifuse 50 which is okay too.
But between Maxifuse 50 and Minifuse 5 there was a 0.4 voltage drop and between Minifuse 5 and terminal A in the EBCTM connector it was also a 0.4 voltage drop .

Are these last two drops acceptable ?

 

Will you also be testing with the engine running?

 

I don't get any more info if the engine was running on these EBCTM circuits .
I am interrested in locating these two 0.4 voltage drops and what it causing it.
I am planning to disconnect the battery and measure resistance between term A on the EBCTM connector and the battery positive cable .
These pieces of wires include two fuses and one of the ignition switch contact sets .
I feel 0.4 volt plus 0.4 volt is to much voltagedrop between Maxifuse 50 and the A terminalof the EBCTM connector

 

I see.

 

You shouldn’t see more than a 0.10 drop across switches and current carrying wires…you may have high resistance in wiring you may not be able to see…if you have piercing probes you can check…just remember that current has to be flowing to do voltage drop testing.

 

"You shouldn’t see more than a 0.10 drop across switches and current carrying wires…you may have high resistance in wiring you may not be able to see…if you have piercing probes you can check…just remember that current has to be flowing to do voltage drop testing."

I fully agree to your values regarding voltage drops and will check into it and that's why I wanted some second opinions on my measurements.
I do have these piercing probes

 

I tried to measure resistance between places in in wiring but it was hard to catch any values above .3 ohms so
I measured 7 places between Battery positive and EBCTM connector pin A (show below).
Main drop is between MinFuse 5 (underhood) and EBCTM pin A .
Just for fun I removed the ignitionswitch for the car and loadtest on my workbench with å powersupply and a load (lamp)
Currentdrop less then 0.2 volt over the OLD IGN swith . (approved)
I then inspected the underhood fusebox MiniFuse 5 fuselocation with the brow wire going to the Pin A of the EBCTM connector.
It was hard to get less then 0.3 ohm resistance in this brown wire include fuse and pin connectors .
I the opened the EBCTM and corrected the spring mechanisme in the pin , cleaned it Deoxit and put everything back together .
I was now able to measure 0.000 ohm between the connector and MiniFuse 5 fuseconnector.
Put the battery back in the car put power on my pin A using the ignition switch.
I also verified my scope channels reading against a powersupply and saw it was some minor difference .
Last measurement shows a drop of approx 0.3 volt between battery positive and Minifuse 5 (underhood) and a 0.16 vol between MiniFuse 5 and EBCTM pin A .
Took some time to do these execises but I enjoy my C5 and using my diagnostic tools on the car