MB Sprinter, battery drained, can't even turn ignition
Just discovered something interesting about my 2016 Sprinter 3500. Our engine battery (under driver's floorboard) drained out while parked for a while. Took off floor covering, mounted my jumper & cables, put key in ignition and...whoops, it won't even turn! Which of course, means you cannot turn over the engine to see if it's taking the charge and starting. AAA came by with a more powerful charger, and with all those extra amps, the dashboard lights lit up and the ignition key could now be fully turned.
No matter how dead the battery, I've never had a vehicle where the ignition couldn't be fully turned. If this is something Mercedes added as an anti-theft ignition lock, why isn't that anywhere in the manual (I searched,) and what does a dead battery have to do with locking the ignition switch anyway
Even the service managers at the two nearby Mercedes dealerships had no idea why the ignition wouldn't turn, and were recommending a very expensive towing job and inspection to find the problem. But the minute the battery had sufficient juice from the AAA truck & cables, the key would turn. Why does nobody know about this and why doesn't the manual make it clear. Must just be that fine German OVER-engineering and UNDER-supporting.
do you have the capacity in such a case to remove the "house" battery and install it in place to run the vehicle?
I can do that with my chev, both batteries are similar in size that I could swap the "house" battery in under the hood.
Could also charge vehicle battery running generator and using a jumper on my battery isolator- to pull charge through house battery -
but that would take awhile
My 2013 Sprinter has under the hood connector to jump the battery, I would assume yours has one as well. I believe it is in the manual, would say it is well engineered and documented.
If your battery was completely discharged all energy from the jumped battery/vehicle was going to charge the dead battery lowering the total voltage below minimum. I had once discharged battery and was able to turn the ignition key buy there wasn’t enough voltage start the engine. Why key didn’t turn I don’t know.
Your chassis battery may be ending its useful life especially if you drain the battery down to where you need to jump start it. As mentioned, you don't have to access your battery under the floor unless you need to replace it. There is a jump start under the hood as GeorgRa's video shows. If you store with a shore power 120V 15a source nearby you could put a Battery Tender Jr. on it. I have a permanently wired Trik-L-Start from my house battery and do much the same storing it with a shore power source through the shore power connection. Though I have a standard RV 30A source I use a 15A adapter with a normal 15a outlet.
__________________ Davydd
2021 Advanced RV 144 custom Sprinter
2015 Advanced RV Extended body Sprinter
2011 Great West Van Legend Sprinter
2005 Pleasure-way Plateau TS Sprinter
Thanks, George for that great little video. I found the red positive connection under the hood. Unfortunately, I'm not finding any indications about that under-hood terminal in the manual. All the topics in the index relating to the battery & charging point to a page of instructions about removing the floor coverings to get at the actual battery under your feet. An oversight, I guess
It appears that it must be my starter dying (after only 30K miles??) With full charging from AAA's high-voltage truck, the dash lights up and the key does turn (it absolutely won't turn without this external charge) there is not even the slightest 'click' sound from the starter. Usually there's at least a little sound of the starter trying to turn. Banging the starter with a rod while I tried the ignition did not help. So it looks like I need to try a new starter (which will mean towing my van if I can't find a mobile tech who can replace it on site.
and the starter SOLENOID which is a switch ( often mounted piggyback)
attempts to crank with a weak battery will often make the solenoid "chatter".
With each chatter carbon is being deposited on the switch contacts from arcing.
These can be serviced and cleaned and are ALOT cheaper than replacing the entire starter assembly
solenoids have a cable directly from the battery- any fault in that cable or a loose connection will render NFG
repair/service 1 thing at a time, reduces the intangibles
you'll be best to test with a known good battery, not from the service truck supplying power ( in which case much of that supplied power is absorbed by the duff battery trying to recharge)
The starter or the starting battery? Are lights dimming when you turn the key to ignition? I would assume your battery is near its end of life, why not start with a new battery instead of a starter.
Lights only lit when battery connected to AAA's truck battery. They did not dim at all when turning the ignition, but no cranking at all. So the AAA driver concluded 'bad starter' because with juice flowing, we should have heard at least a bit of the starter moving & trying. But if that was the wrong conclusion, happy to investigate other parts.
The vehicle has less than 30K on it and has been driven very little, so I'd be a bit surprised if battery was already near the end of its life.
"solenoids have a cable directly from the battery- any fault in that cable or a loose connection will render NFG"
Thanks. Is there a way to clearly locate that cable, so I can check for fault or loose connection?
Quote:
Originally Posted by mkguitar
starter have 2 parts
the electric motor which turns the engine
and the starter SOLENOID which is a switch ( often mounted piggyback)
attempts to crank with a weak battery will often make the solenoid "chatter".
With each chatter carbon is being deposited on the switch contacts from arcing.
These can be serviced and cleaned and are ALOT cheaper than replacing the entire starter assembly
solenoids have a cable directly from the battery- any fault in that cable or a loose connection will render NFG
repair/service 1 thing at a time, reduces the intangibles
you'll be best to test with a known good battery, not from the service truck supplying power ( in which case much of that supplied power is absorbed by the duff battery trying to recharge)
Your chassis battery may be ending its useful life especially if you drain the battery down to where you need to jump start it.
Maybe, maybe not. Batteries can be hard to fathom...
Mine had sat for ten months- through a whole Mid-Atlantic winter- with the chassis battery discharged. When Mom handed over the keys, I was certain a new battery would be needed. Cleaned it up, jump-started it, drove it to Arizona, and two years later it still cranks right up after sitting a month. I did have it tested at a Walmart during the first leg of the drive- tested okay. It's the original Chevy battery, almost 6 years old now. Go figure!
You could have it load tested.
__________________
2014 Roadtrek 190 Popular
2008 Scamp 13
We had a somewhat similar battery thing with a car, but it didn't have the no key turn problem with it.
DW's car wouldn't start at the shopping center so I went to look. Dash lights came on but dim and went totally out when key turned. Figured low battery so jumped it after charging from my car for 10 minutes. Lights bright with my car still attached, turn the key and get nothing and the lights go out and my car nearly dies. Let off the key all good again. Figured bad starter and towed it home.
All set to pull starter and on a whim figured I would load test the battery which was still able light the lights. Put on the load tester read 12.3v and pushed the test button. Instantly dropped to zero volts. Let off the test button and lights came back on. Bottom line was loose internal battery connection it appears that would open under large load and be OK on light loads. New battery fixed it. I would have bet a lot of money on it being the starter, but it wasn't.
The point is that batteries or bad connections can make for some very odd symptoms sometimes. I have never ever seen a car that wouldn't turn over when jumped just from and bad battery that could still light the lights.
We had a somewhat similar battery thing with a car, but it didn't have the no key turn problem with it.
DW's car wouldn't start at the shopping center so I went to look. Dash lights came on but dim and went totally out when key turned. Figured low battery so jumped it after charging from my car for 10 minutes. Lights bright with my car still attached, turn the key and get nothing and the lights go out and my car nearly dies. Let off the key all good again. Figured bad starter and towed it home.
All set to pull starter and on a whim figured I would load test the battery which was still able light the lights. Put on the load tester read 12.3v and pushed the test button. Instantly dropped to zero volts. Let off the test button and lights came back on. Bottom line was loose internal battery connection it appears that would open under large load and be OK on light loads. New battery fixed it. I would have bet a lot of money on it being the starter, but it wasn't.
The point is that batteries or bad connections can make for some very odd symptoms sometimes. I have never ever seen a car that wouldn't turn over when jumped just from and bad battery that could still light the lights.
I agree, it is likely the battery - it could be shorted so all energy is going to heat cables and battery. A little voltmeter can diagnose this in seconds as pointer earlier, is there 12V on the starter's positive connection, I bet it is not.
A fully discharged battery will take a while to recharge to a useable condition. Get yourself a decent battery charger of at least 50 amps and connect it to the under hood terminals and let it on for a few hours or overnight if you have that much time. If the battery is good it will accept the charge and be ok. If it doesn’t replace it.
My 2016 Sprinter will self drain in less than a week unless you disconnect the negative line at the connection above the accelerator pedal.
I keep it plugged in to shore power when not used to allow the converter to keep it charged or if parked in the sun the solar panels keep it charged.
On our 2015 Promaster, the key also will not turn at all when the battery very low, which we have had too many times to observe. I would not replace the starter first. Maybe this is more common in newer vehicles.
I had an issue with a 2008 Roadtrek Adventurous. Wouldn't start, acted like battery dead, not even a click when ignition turned, but main battery fully charged. Mercedes completely baffled. Paulsbo RV quickly diagnosed the problem. The Sprinter starter system runs through a series of computerized checks before engaging the starter motor. The house batteries are in the loop. So although the main battery that runs the starter motor was fully charged, the house batteries were dead. The electronic ignition was receiving a signal through the house batteries that there was no juice to turn the motor. I have no idea if makes other than Roadtrek in that model year wired the ignition system this way. It seems counter intuitive that dead house batteries should kill the ignition system, but it is worth a check
Here is a link to the mercedes sprinter manuals page. The 2016 manual has a description of the underhood jump start connections and instructions on pages 242-243. I know this may be obvious, but is the transmission in park?
MB Sprinter, battery drained, can't even turn ignition
if I can't find a mobile tech who can replace it on site.
Linear Mode
