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Hello, I've had the AUX battery malfunction sign for 1 yr even after a genuine battery replacement then finally went to the dealer for the diagnostic.
They said it needs a DC VOLTAGE CONVERTER which costs $425part + $500 labor....
I have a salvage yard near me but need to know where they heck is this DC voltage converter located.
I looked near the battery compartment but can't see to find it. Anyone has access to a diagram and can screenshot for me the location?
Part: a164 542 00 25
2010 GL450 (x164)
A1645420025 is the "DC voltage converter", which to me looks like a capacitor not a battery. It has short electrical leads/cables.
N000000004039 is the "battery backup 1.2AH" and is a gel cell battery, most often referred to as the auxiliary battery.
The main starting battery and N000000004039 are under the front passenger seat, adjacent to each other. If it were my vehicle, I would look in this area near both batteries.
What is your VIN? Do you have a 48V system? The A1645420025 is shown in EPC but I haven't found a corresponding procedure in WIS.
A1645420025 is the "DC voltage converter", which to me looks like a capacitor not a battery. It has short electrical leads/cables.
N000000004039 is the "battery backup 1.2AH" and is a gel cell battery, most often referred to as the auxiliary battery.
The main starting battery and N000000004039 are under the front passenger seat, adjacent to each other. If it were my vehicle, I would look in this area near both batteries.
What is your VIN? Do you have a 48V system? The A1645420025 is shown in EPC but I haven't found a corresponding procedure in WIS.
Thank you for the reply. So initially when the aux battery malfunction sign popped up I sought to replaced the aux battery and at the same time the main battery. Upon visual both batteries were never replaced since the vehicle production. So I thought to change both and even replacing it with the genuine MBenz aux battery got a purchase from Benz dealer, the sign never went away.
1yr passed and I thought to have vehicle diagnosed by Benz for $295. They said 100% it needs a "DC Voltage" part: A1645420025. Labor +part = ~$1,100. I declined and went home then removed both aux & main battery to see if I can see the part. I couldn't. It's hidden. Im seeing if someone can screenshot me the location with their software (perhaps) they use to work on their vehicle on where I can find this.
Based on the diagram, component 'F33 - Battery Compartment Prefuse Box' (large square in diagram) connects with 'N99 - DC/DC Converter Control Unit' and appears to be housed in the Battery compartment as per bottom left blow-out photo.
Based on the diagram, component 'F33 - Battery Compartment Prefuse Box' (large square in diagram) connects with 'N99 - DC/DC Converter Control Unit' and appears to be housed in the Battery compartment as per bottom left blow-out photo.
This makes sense.
MB+, what is your VIN, and do you have ECO start/stop or 48V systems on your vehicle?
Hi guys so I took the liberty in taking a few pic of the area
I don't have the eco-start option or the push button. I have to insert key and turn. During the diagnostic they thought it may be the aux battery so they changed it to new one free under warranty but sign still remained thus them saying it was the DC voltage converter. This is what it looks like now. Disregard the BLUE wires they are of aftermarket speakers which were installed many years prior to the malfunction sign.
Which is where we are now.
Based on a C-Class video and the diagram linked by Miguk, I would dig around under the front passenger footwell, and on the side (end) of the instrument panel. Still haven't found it in WIS.
Hi guys so I took the liberty in taking a few pic of the area
I don't have the eco-start option or the push button. I have to insert key and turn. During the diagnostic they thought it may be the aux battery so they changed it to new one free under warranty but sign still remained thus them saying it was the DC voltage converter. This is what it looks like now. Disregard the BLUE wires they are of aftermarket speakers which were installed many years prior to the malfunction sign.
Which is where we are now.
See pic. VIN-- Pm'd
AUX Battery
nice and dry in there - should be a good running GL when this is sorted.
Also, having been around some incompetent service advisors in the past who were not good at taking the specs from the engineers to the customer; have you ruled out that your car just needs a VOLTAGE REGULATOR?
that thing sits on the alternator and is a breeze to replace once it’s out.
Last edited by Max Blast; Jan 26, 2020 at 10:07 PM.
Base on the provided diagram, it appears that the second fuse from either the TOP or BOTTOM is the fuse for the converter. Pull out your trusty multi-meter, pop out the fuse, and test for continuity on that circuit. If you can isolate the fuse, then you can just tap the new DC converter into the slot to see if it resolves your issue (or maybe the fuse is blown).
Beyond the above suggestion, the only other thing I have been able to find is from the E-Class repair manual, where the 'N99 - DC/DC Converter control unit' is for the heated steering wheel and is located inside the dash behind the instrument panel (I have not been able to find the same documentation for the x164). Does your x164 have a heated steering wheel? If so, is it currently functional? If it is not functional, then maybe that's your culprit.
Click on the [Prev Page] button for additional views on part location (pages 17383 - 17385).
Of course (and maybe you could have tried this first), you could always just ask the Mercedes Tech or Service Mgr to tell you where the component is located and/or what exactly is involved in replacing the component... just sayin....
Last edited by Miguk_Saram; Jan 27, 2020 at 09:27 AM.
Hi everyone!!! @ Max Blast -- I can replace the voltage regulator I've seen how to on youtube. Might as well start there.
@ Miguk_Saram -- I checked all 3 fuse location before heading to dealer : engine, driver panel, battery panel, rear truck panel, all fuses work. Vehicle never came with eco-start or heated steering...though it would such a nice feature to have.
I removed the front passenger side carpet and foot-area panels to see if its there, nope.
Do anyone know of a friends friends, friends friend of a girlfriend's friend who works for MBenz and find out the location? One call from you can save a man from having to pay an arm and leg. And help save a puppy.
Last edited by MB+; Feb 6, 2020 at 10:37 PM.
Reason: Wrong image added
The DC converter that they offer to install is a fix for charging the aux battery, it is normally not present in any car.
The aux battery is normally charged from the N10 - front SAM and monitored by the same module, but if you happen to drive a lot of short trips, the front SAM can't keep up with the charging process so MB offer to install the DC converter, which is connected directly to the aux battery terminals in parallel to existing leads for plus and minus.
The DC converter is basically a small battery charger that feeds the aux battery with 13,2volts at 100mA (float charge level of battery), while your car is driving. it is important that the battery is not charged with higher voltage or current at this stage, otherwise it will cook the battery.
The supply to the DC converter is connected with plus to pin11 of connector-C (pink wire) on the front SAM ond minus to ground, the secondary side of the DC converter is connected to the aux battery in parallel with existing plugs.
The DC converter is very small and should easily fit in the battery compartment.
The DC converter that they offer to install is a fix for charging the aux battery, it is normally not present in any car.
The aux battery is normally charged from the N10 - front SAM and monitored by the same module, but if you happen to drive a lot of short trips, the front SAM can't keep up with the charging process so MB offer to install the DC converter, which is connected directly to the aux battery terminals in parallel to existing leads for plus and minus.
The DC converter is basically a small battery charger that feeds the aux battery with 13,2volts at 100mA (float charge level of battery), while your car is driving. it is important that the battery is not charged with higher voltage or current at this stage, otherwise it will cook the battery.
If you want to DIY, here is a video: https://www.youtube.com/watch?v=3z29dYfNf8Y
The supply to the DC converter is connected with plus to pin11 of connector-C (pink wire) on the front SAM ond minus to ground, the secondary side of the DC converter is connected to the aux battery in parallel with existing plugs.
The DC converter is very small and should easily fit in the battery compartment.
This video is excellent, thanks for posting @KVA73
@KVA73 Thank you for the insightful video. I had watched this video many days back shortly after the part # was given. It was not in English. How you got it to be in English with instructions I thank you. Same day I called two other Benz dealer in FL and neither knew the location even using their dealer software they do for repairs. They did say that it is showing that it matches the part with VIN but they can't locate where the part goes, now we know why because this converter is not installed factory. I do take short trips locally. I want to thank you for this.
Would anyone know... If other lights or errors will come on if I remove the front passenger seat (unplug the connecting wire) for better access for this repair? Currently the bolts are removed and seat pushed forward as possible.... But will it be safe to unplug the wires from under the seat without causing any issues if plugged back in? Dashboard or else what.
@chassis You've been helpful as well thank you for looking out.
Removing the seat will set an airbag light that dealer will have to extinguish, unless you have the equipment to do so. This applies to middle row seats too, btw.
Removing the seat will set an airbag light that dealer will have to extinguish, unless you have the equipment to do so. This applies to middle row seats too, btw.
Okay then I'll leave the seat as if and will work as so. Thanks for the heads up. ☺️
Okay then I'll leave the seat as if and will work as so. Thanks for the heads up. ☺️
A fairly inexpensive OBD reader with SRS function will reset the SRS (Safety Restraint System) for you. The cost is less than a dealer would charge for the reset and it can be used with other makes and models (not just Benz).
After carefully watching the video there is a dilemma that I've run into.
All other wiring will go as instructed except coupling which I have labeled "F", am I to splice it into something.
I've carefully examined all areas of the compartment and found no coupling anywhere. Maybe I'm missing something in the video which someone can point out?
Allow me to thank each and everyone of your for all your help. @chassis I've took your suggestion and am confident that I'll be able to splice and connect the wiring; however not wanting to cross wire and cause another headache I've purchased the mentioned below @KVA73 You've said exactly what a senior tech said at MB during my visit today! @Miguk_Saram Appreciate the links and suggestion
I've ended opting in getting the part directly from MB and using KVA73 video. Reason why is MB parts provides a male & female coupling pictured below while others may not. One coupling has a pigtail wire.
Some info to consider: anyone who finds themselves in this situation where they have a AUX battery malfunction even after a new aux battery installed and a R series GL series and some cars from 2007-2014 may want to see if this may fix it. It FIXED MINE. Thank you to each and everyone of you for your input, links, and videos.
THANK YOU EVERYONE THANK YOU EVERYONE
THANK YOU EVERYONE THANK YOU EVERYONE
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Help me location ----- DC Voltage Converter
One call from you can save a man from having to pay an arm and leg. And help save a puppy.
