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may be this inline 100Amp link is physically built-in the R-SAM near the landing post for the fat red cable....
or the opposite: built-in near the output post of the ECO relay.
A 100Amp link may look like is a piece of metal or encasulated in epoxy as seen in PreFuse module.
Pic shows a chunky magnetic relay where newer style feature a smaller solid state relay.
I recall the R-SAM as being the module tasked with managing the 12.6V float operations when you car deeps down after the quick charge cycle.
I guess this 100Amp F97 is an invitation to get up close and intimate with R-SAM circuitry.
Benz did manage to hide a tiny bit from ya...
Are you getting power related DTC in your R-SAM complaining about "low voltage... circuit 30..." ?
R-SAM does have the ability to mesure voltages, just not current like the shunt sensor on battery (-). What I mean is R-SAM monitors the power in that circuit.
01. F97 can't be built into the relay K114. Because of the way MB wired the wires, the F97 will instead protect the ECO battery and not the N10/2 Rear SAM if the relay has the built in F97.
Terminal 3 and 4 of K114 relay is actually a single terminal, not 2 as schematic indicated. 2 wires there yes, but ihey share the same stud.
02. Mr K Wote : Looks like it’s inline between additional battery relay and rear SAM.
As per schematic it is indeed between K114 to rear SAM.
or
It can also be at rear SAM hidden behind from view , proably located at the cable entry region, if we based on the location info image below.
I used my inspection camera 10 minutes ago looking at the back of the Rear SAM trying to find a bolt type connection suitable for such a fuse F97 ( #415) is.
Too cramp a view and I can't confirm anything and most likely the F97 is probably somewhere inside the rear SAM or not there at all.
Next possibility is MB placed F97 at the plastic cable trunk. Here is a photo when I was replacing shock absorber bushing.
Rule of thumb for fuse is to be as close as possible to power source.
Since B03 ECO is a short production run, I won't be suprised if F97 is housed in a plastic box stashed somewhere in the plastic cable trunk middle part or close to rear SAM.
============================
I think I been looking at the rear SAM the wrong way.
Aside from the SAM computers, strictly only fuses/relay part, Fuse assignment of Rear SAM document is ONLY for outgoing fuses,
F97 is INPUT fuse.
If the car is not B03 ECO, F32 will be the one providing INPUT fuse protection for N10/2 Rear SAM.
Now the car is B03 ECO and has the baby G1/13 12Ah battery, F97 must be installed as when the baby battery engaged/active unless there is an F97, it won't be safe for the baby battery to send
power on a 10mm cable totally unprotected.
========================
Damn, I got to open up again the trunk lining to find F97...
Again, thanks guys.
Last edited by S-Prihadi; Jun 5, 2021 at 10:42 PM.
I guess this 100Amp F97 is an invitation to get up close and intimate with R-SAM circuitry.
Benz did manage to hide a tiny bit from ya...
Are you getting power related DTC in your R-SAM complaining about "low voltage... circuit 30..." ?
R-SAM does have the ability to mesure voltages, just not current like the shunt sensor on battery (-). What I mean is R-SAM monitors the power in that circuit.
I dont have any issue with DTC. I just need to know where are fuses located. Its the itchy me now at work ..LOL
or without exactly seeing F97, you can assume it is somewhere in between and measure voltage on both end of the red cable.
The R-SAM is an impressive module with weird legacy implementation. The front MAIN battery sensor is directly connected to it from when MAIN used to be hidden under passenger seat and trunk space
Last edited by CaliBenzDriver; Jun 6, 2021 at 01:39 AM.
I want to know more about my car and I need to know where fuses are located, all of them. More so it such fuse, that F97... can take down entire circuit 30 of Rear SAM.
F32 at IM1 terminal is one of the power provider for rear SAM and also it connects to the baby Eco battery, this is circuit 30 category and F97 is a part of it if a car is B03 ECO option.
F32 at IG1 terminal also provide power for rear SAM, but this is a 30g circuit, it is via K2 relay.
If I did not pay attention to a stand alone fuse, that F97 , I would assume all main power be it 30 or 30g/switched is from F32.
This F97 is a last minute cheap fix by MB for B03 ECO cars if indeed it is hidden at the plastic wire trunk or near rear SAM.
If I were the designer, I would place an F97 fuse block next to K114 Eco Battery Relay because that is how a main power fuse is supposed to be from a safety point of view,
as close as possible to power source, of which in this case the baby ECO battery is the power source* ( *when K114 engaged ).
If I can get a nice fuse block with good insulator casing, maybe high end audio fuse block like below :
I will remove F97 and make this the new F97 and placed nearest to baby Eco battery
I have located your most wanted 100Amp F97 that supplies the Rear-SAM consumers directly from PreFuse.
Here you go... Spotted Fuse97... in-line ✌️
It's connected on the feed side of the AUX battery relay.
-------------
Personally, I just wanted to check if the MOSFET relay was rocking a solderless control board... but I can't tell because it is all encapsulated in white silicon gel.
So these MosFet solid state are looking pretty reliable despite signs of heat.
While working near AUX battery, check the GND screw to chassis if plagued with repeated AUX issues. check your AUX GND AL screw...
From the outside it looks all right but when you look closer the nut tightening on the steel screw is loaded with dusty white aluminum oxide, a known insulator!
Unlike the main battery GND that uses a proper brass nut, the choice of this aluminum nut almost guaranties a visit to the shop 😆
In contrast the thick power cables are built to greater standards with crimp abd soldering.
👍
Last edited by CaliBenzDriver; Jun 12, 2021 at 12:55 AM.
Reason: AUX GND...
YOU SIR, AWESOME !!!!!! Thank you x 1 million
Dang, they used soldered type fuse on a special cable lug. I never seen one doing this yet, because it is not so easy to replace.
While working near AUX battery, check the GND screw to chassis if plagued with repeated AUX issues. check your AUX GND AL screw...
From the outside it looks all right but when you look closer the nut tightening on the steel screw is loaded with dusty white aluminum oxide, a known insulator!
Unlike the main battery GND that uses a proper brass nut, the choice of this aluminum nut almost guaranties a visit to the shop 😆
In contrast the thick power cables are built to greater standards with crimp abd soldering.
👍
I have not touched that trunk ground nut or stud yet. Will check. It does look clean when I was doing rear shock absorber.
The rest upfront I inspected using magnet to see if any stud or nut is aluminum. I worry about alu oxide too. They are steel.
I know my front fender is alu and so is my hood/bonnet. Front Suspension well is steel.
I think this 100Amp fuse is to prevent fire hazard in case of a severe accident crushing the SAM wiring.
In normal conditions this fuse should never blow and if it does blow, you can replace the short 2Ft cable feeding SAM.
As far as fuse voltage drop, it should be minimal to accept 100Amp without interfering... 200mV??
--------
The nasty part is the oxidized AUX GND screw. The upgrade would be brass or stainless steel, not aluminum over steel
🙂
That F97 100 amp fuse wont blow unless there is a short circuit. Its more of a power feed protection and not devices/consumers protection per se.
I am curious to see how the fuse is designed. It must have an insulating "backing plate", which is the stiff part physically providing strength to the fuse body.
Common 100A ANL fuse like below :
....will physically break/bend if it were to be soldered to a wire lug and carry the weight load of a cable.
I suspect the fuse has PCB type fiberglass material the length of the entire fuse assy as stiffener as it has no housing to house the fuse.
Typical fuse housing
Last edited by S-Prihadi; Jun 12, 2021 at 03:01 AM.
Reason: add image
the GND nut for AUX had a lip from factory... so I filled it smooth for a wider contact area: it is as soft as butter: AL begging for antioxidant compound.
Your replacement fuse holder shows nice stainless steel posts and nuts.
🤗
----- EDIT...
Nut is not pure AL but a light cast alloy with little magnetic properties.
Last edited by CaliBenzDriver; Jun 13, 2021 at 12:34 AM.
You can replace light alloy GND nuts with stainless steel nuts as used on the MosFet relay
-or prevent oxidation by using antioxidant compound. I picked the second choice.
Managed quality:
Benz managers specified the use of brass and stainless steel grounding nuts but for lesser power circuits (1 to 15A) , they decided to save boat load of pennies 🤗
Low power COM circuits:
Given time and conditions alloy nut does oxidize regardless of current. The "smart modules" will then begin to act goofy with communications unreferenced to GND.
Evidences point to a gamut of amazing problems (*) added to warrant service needs
🙂
(*) Opportunities Such As....:
under lubed mechanisms,
unsoldered module connector pins,
removed oil check valves,
soft steel phaser pins,
unrestricted intake oil swamp,
untested firmware compatibility,
variable voltage....
aluminum fasteners... LoL,
under sized O-rings
.?.
very sofisticated practice
🤗
Last edited by CaliBenzDriver; Jun 13, 2021 at 12:45 AM.
Reason: tipos 😏
Here we are two advanced scuba divers, Benz owners who like to check their gear before trusting it with our life.
Looking from a far, I'd say we both used to check electricals systems from the bottom up: from supply to consumers the same way we check diving gear methodically.✌️
Last edited by CaliBenzDriver; Jun 13, 2021 at 12:27 AM.
I will replace those nuts with Stainless ones when I am done testing them and indeed they are alu. My market may be different than USA version, hopefully nuts are steel
the good news is nut respond to magnetism so there is some iron in it. The flip side is the lip all around is leftover spray paint.
I guess the nuts are pre installed with GND posts before paint job is applied. making R-SAM and AUX 👍
I am cleaning the GND connections when I encounter them. Some show sign of oxidation under hood and trunk.
Last edited by CaliBenzDriver; Jun 13, 2021 at 01:16 AM.
ALL fuses are to protect the wiring from burning up in case of a short, they are NOT device/consumer protection.
What I meant to say is, F97 at 100 amps is protection for Rear SAM as a whole, because it is a power feed fuse aka main fuse.
It does not protect each devices, which has its own fuses already.
Depends on fuse size, if well sized it will protect device and cable to device
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Thank you x 1 million 
dang
