Hello MBWorld
05-31-2017, 05:23 AM
#1
Newbie
Thread Starter
Hello MBWorld
Hi please help I have a c250 cdi 2012 which the battery die on, so replaced the battery. Unfortunately before that I jump started it incorrectly.
All features and electronics are working correctly apart from the ac heater controls in the cabin, also the engine fan is running at full speed, any ideas from MB owners would be greatly appreciated before heading to the dealership.
Thanks in advance
C250 Coupe 2012
All features and electronics are working correctly apart from the ac heater controls in the cabin, also the engine fan is running at full speed, any ideas from MB owners would be greatly appreciated before heading to the dealership.
Thanks in advance
C250 Coupe 2012
05-31-2017, 07:32 AM
#2
Newbie
Thread Starter
C class w204 2012 coupe
Hi please help I have a c250 cdi 2012 which the battery die on, so replaced the battery. Unfortunately before that I jump started it incorrectly.
All features and electronics are working correctly apart from the ac heater controls in the cabin, also the engine fan is running at full speed, any ideas from MB owners would be greatly appreciated before heading to the dealership.
Thanks in advance
C250 Coupe 2012
All features and electronics are working correctly apart from the ac heater controls in the cabin, also the engine fan is running at full speed, any ideas from MB owners would be greatly appreciated before heading to the dealership.
Thanks in advance
C250 Coupe 2012
06-02-2017, 09:17 AM
#4
MBWorld Fanatic!
Battery die on? <--what?
Jump started it incorrectly? - how?
Worst case you fried your ECU and everything. Have you checked the fuse box?
This could be a butt expensive repair.
Jump started it incorrectly? - how?
Worst case you fried your ECU and everything. Have you checked the fuse box?
This could be a butt expensive repair.
The following users liked this post:
C250 coupe 2012 (06-03-2017)
06-03-2017, 02:56 AM
#5
Newbie
Thread Starter
Thanks for the reply my friend, to clarify:-
1- The battery was 5 years old and a AGM stop/start technology type, which was fitted when the vehicle was manufactured, therefore getting to an age where it was feeling laboured when starting.
2- One morning the battery did not have the power to crank the engine, so I jump started the car incorrectly via the battery terminals and not the jumping points.
3- The engine started and all was well apart from the air control module in the cabin of the vehicle have no light, and appeared to have no power to it.
4- In conjunction with the ac being inoperable, the engine fan was running at full speed.
I have spoken to my local MB dealer and he has informed me that, when the ac fails the engine fan runs at high speed as a precaution.
I hear what your saying in regards to frying the ECU, but do you feel all other electronic devices would be running correctly it this was the case?- I am praying not!!!
I have checked all fuses twice as a starting point.
I have found 1 thread on MB forum where a guy had the same symptoms, and replaced the ac heater unit in the dash, with the same unit with the same HW and SW comparability.
I have found this item on eBay and will fit the replacement to see if it solves the issue.
I,m expecting to find numerous faults when it is put on diagnostic after that.
Any of your comments and any advice greatly received!
Cheers
C250 coupe 2012
1- The battery was 5 years old and a AGM stop/start technology type, which was fitted when the vehicle was manufactured, therefore getting to an age where it was feeling laboured when starting.
2- One morning the battery did not have the power to crank the engine, so I jump started the car incorrectly via the battery terminals and not the jumping points.
3- The engine started and all was well apart from the air control module in the cabin of the vehicle have no light, and appeared to have no power to it.
4- In conjunction with the ac being inoperable, the engine fan was running at full speed.
I have spoken to my local MB dealer and he has informed me that, when the ac fails the engine fan runs at high speed as a precaution.
I hear what your saying in regards to frying the ECU, but do you feel all other electronic devices would be running correctly it this was the case?- I am praying not!!!
I have checked all fuses twice as a starting point.
I have found 1 thread on MB forum where a guy had the same symptoms, and replaced the ac heater unit in the dash, with the same unit with the same HW and SW comparability.
I have found this item on eBay and will fit the replacement to see if it solves the issue.
I,m expecting to find numerous faults when it is put on diagnostic after that.
Any of your comments and any advice greatly received!
Cheers
C250 coupe 2012
06-03-2017, 08:28 AM
#6
MBWorld Fanatic!
Couple of points:
In reference to: "2- One morning the battery did not have the power to crank the engine, so I jump started the car incorrectly via the battery terminals and not the jumping points."
Good thing this is all that you did! I mean, I'm not concerned that you fried your ECU or anything then, because there's nothing wrong with jumping a car via battery terminals vs jumping points. It's the same idea.
Bad thing is then I have no idea what the issue would be. Sorry!
In reference to: "2- One morning the battery did not have the power to crank the engine, so I jump started the car incorrectly via the battery terminals and not the jumping points."
Good thing this is all that you did! I mean, I'm not concerned that you fried your ECU or anything then, because there's nothing wrong with jumping a car via battery terminals vs jumping points. It's the same idea.
Bad thing is then I have no idea what the issue would be. Sorry!
06-07-2017, 05:03 PM
#7
Newbie
Thread Starter
Anyone considering jump starting a Mercedes via the battery terminals, Don't Do It!, doing so sends a surge to electrical components and will cause damage.
I'm my instance it burnt out the ac control unit in the dash, lucky I found a used replacement online, if you can find a used one with the same hardware and software codes you can do a direct swop without having a MB dealer reprogram it.
After replacing the ac module the engine fan returned to normal speed and the aircon reset itself and is blowing a blizzard.
Hope this helps a fellow MB owner
I'm my instance it burnt out the ac control unit in the dash, lucky I found a used replacement online, if you can find a used one with the same hardware and software codes you can do a direct swop without having a MB dealer reprogram it.
After replacing the ac module the engine fan returned to normal speed and the aircon reset itself and is blowing a blizzard.
Hope this helps a fellow MB owner
Trending Topics
06-08-2017, 04:57 PM
#9
MBWorld Fanatic!
I would be grateful to know what the difference is between jump starting on the battery terminals Vs placing the jumper lead clips on the terminals under the bonnet ?.
What is different when replacing a battery with a fully charged one ? .The battery terminals are used & the voltage goes from 0 to 12 volts instantaneously.
In my opinion, two methods may help in not damaging the electrical system.Make sure the key is removed from the ignition & the system has gone to "sleep" before disconnection begins & the donor car engine is not running ie increasing the voltage to 14.5 volts.
I would like to hear more good advice on the issue.
C250 Coupe ,did you remove the key & what was the source of the jump start? Thanks.
What is different when replacing a battery with a fully charged one ? .The battery terminals are used & the voltage goes from 0 to 12 volts instantaneously.
In my opinion, two methods may help in not damaging the electrical system.Make sure the key is removed from the ignition & the system has gone to "sleep" before disconnection begins & the donor car engine is not running ie increasing the voltage to 14.5 volts.
I would like to hear more good advice on the issue.
C250 Coupe ,did you remove the key & what was the source of the jump start? Thanks.
06-08-2017, 09:19 PM
#10
Newbie
Thread Starter
Hi Carsey,
I'm no electrical wizard, I wouldn't of carried out the procedure I did if I was lol.
I called the RAC initially after making a mess of jump starting my merc from another vehicle which was running at the time.
The RAC guy who was in my mind very knowledgeable off Mercedes vehicles explained it to my like this:- due to my vehicle having numerous sensitive electrical components and computers, jump start points are added to the vehicle to by pass these when jump starting, the current and cranking amps can effectively be doubled by adding a running second vehicle to enable the battery on my car to have sufficient amps to fire up the vehicle.
The charge you are putting through the jumping points goes through the SAMS module which has a number of rated fuses to deal with an overload where as jumping through the battery terminal points directly effects your cars electrical components.
When I think about what this guy told me it makes sense.
Happy days my merc is back to fully working order.
Cheers!
I'm no electrical wizard, I wouldn't of carried out the procedure I did if I was lol.
I called the RAC initially after making a mess of jump starting my merc from another vehicle which was running at the time.
The RAC guy who was in my mind very knowledgeable off Mercedes vehicles explained it to my like this:- due to my vehicle having numerous sensitive electrical components and computers, jump start points are added to the vehicle to by pass these when jump starting, the current and cranking amps can effectively be doubled by adding a running second vehicle to enable the battery on my car to have sufficient amps to fire up the vehicle.
The charge you are putting through the jumping points goes through the SAMS module which has a number of rated fuses to deal with an overload where as jumping through the battery terminal points directly effects your cars electrical components.
When I think about what this guy told me it makes sense.
Happy days my merc is back to fully working order.
Cheers!
The following users liked this post:
dieseldoc (06-08-2017)
06-08-2017, 09:52 PM
#11
MBWorld Fanatic!
06-08-2017, 10:03 PM
#12
Newbie
Thread Starter
Sure it makes no difference!! Mercedes have added jump starting points
to there vehicles as an item of beauty, and not for any
usable purpose, PLEASE have you heard yourself?
to there vehicles as an item of beauty, and not for any
usable purpose, PLEASE have you heard yourself?
06-08-2017, 10:40 PM
#13
MBWorld Fanatic!
I would like an explanation also. I have had multiple Mercedes as well as other German cars. On my Mercedes GL as well as well as several of my BMWs the Battery was not in the engine compartment but in places like under the passenger seat or rear seat. I always thought the jump start points under the hood were there as a matter of convenience. Mercedes's medic has a section on how to properly jump your Mercedes without hurting electronics.
06-09-2017, 03:33 AM
#14
MBWorld Fanatic!
Hi Carsey,
I'm no electrical wizard, I wouldn't of carried out the procedure I did if I was lol.
I called the RAC initially after making a mess of jump starting my merc from another vehicle which was running at the time.
The RAC guy who was in my mind very knowledgeable off Mercedes vehicles explained it to my like this:- due to my vehicle having numerous sensitive electrical components and computers, jump start points are added to the vehicle to by pass these when jump starting, the current and cranking amps can effectively be doubled by adding a running second vehicle to enable the battery on my car to have sufficient amps to fire up the vehicle.
The charge you are putting through the jumping points goes through the SAMS module which has a number of rated fuses to deal with an overload where as jumping through the battery terminal points directly effects your cars electrical components.
When I think about what this guy told me it makes sense.
Happy days my merc is back to fully working order.
Cheers!
I'm no electrical wizard, I wouldn't of carried out the procedure I did if I was lol.
I called the RAC initially after making a mess of jump starting my merc from another vehicle which was running at the time.
The RAC guy who was in my mind very knowledgeable off Mercedes vehicles explained it to my like this:- due to my vehicle having numerous sensitive electrical components and computers, jump start points are added to the vehicle to by pass these when jump starting, the current and cranking amps can effectively be doubled by adding a running second vehicle to enable the battery on my car to have sufficient amps to fire up the vehicle.
The charge you are putting through the jumping points goes through the SAMS module which has a number of rated fuses to deal with an overload where as jumping through the battery terminal points directly effects your cars electrical components.
When I think about what this guy told me it makes sense.
Happy days my merc is back to fully working order.
Cheers!
The following users liked this post:
C250 coupe 2012 (06-09-2017)
06-09-2017, 03:34 AM
#15
MBWorld Fanatic!
I would like an explanation also. I have had multiple Mercedes as well as other German cars. On my Mercedes GL as well as well as several of my BMWs the Battery was not in the engine compartment but in places like under the passenger seat or rear seat. I always thought the jump start points under the hood were there as a matter of convenience. Mercedes's medic has a section on how to properly jump your Mercedes without hurting electronics.
06-09-2017, 11:43 AM
#16
MBWorld Fanatic!
Originally Posted by Carsy
Grateful if you could post it Dieseldoc.
Last edited by dieseldoc; 06-09-2017 at 12:10 PM.
The following users liked this post:
Carsy (06-09-2017)
06-09-2017, 05:09 PM
#17
MBWorld Fanatic!
Thank you Jeff, This is an interesting subject.
I left the ign key on acc for nearly a week ,many years ago ,which completely drained the battery .
My ultra modern & also my old battery charger would not charge the battery. It seems that battery chargers do need some voltage present to charge.
The way I got around this was to remove the ign key , let the elec. system go to sleep, then connected a donor battery via jumper leads. I then connected the battery charger & left it charging all day with both batteries connected.
This method did not damage the car electrics & the battery is still in use after 10 years.
The dilemma I face is ,should I replace the battery before it show signs of failing. I have read here of damage to alternators with failed batteries & also when away from home where I do not have the facilities & time to do a slow charge or source the correct Absorbed Glass Mat 70 amp hour battery.I am leaning towards replacing soon.
Whilst we are at it , with the sensitivity of the modern car electrical system, what method should be adopted in changing batteries? . To prevent sudden voltage surges it may be useful to connect a donor battery to the front terminals before removing the battery terminals?.
Input welcome.
I left the ign key on acc for nearly a week ,many years ago ,which completely drained the battery .
My ultra modern & also my old battery charger would not charge the battery. It seems that battery chargers do need some voltage present to charge.
The way I got around this was to remove the ign key , let the elec. system go to sleep, then connected a donor battery via jumper leads. I then connected the battery charger & left it charging all day with both batteries connected.
This method did not damage the car electrics & the battery is still in use after 10 years.
The dilemma I face is ,should I replace the battery before it show signs of failing. I have read here of damage to alternators with failed batteries & also when away from home where I do not have the facilities & time to do a slow charge or source the correct Absorbed Glass Mat 70 amp hour battery.I am leaning towards replacing soon.
Whilst we are at it , with the sensitivity of the modern car electrical system, what method should be adopted in changing batteries? . To prevent sudden voltage surges it may be useful to connect a donor battery to the front terminals before removing the battery terminals?.
Input welcome.
