Electrical problems: where to begin?

Hi guys, I just got a 2006 sprinter for cheap with 77 000 kms that had an electrical problem. I managed to drive it out of the dealers yard and make my way home but I drove the whole way in limp mode.

Here are the key things that should be taken into consideration IMO:

-Two wrenches appear in the dash when starting, I had never seen this.
-Trying to start the engine with the key does nothing (no click), but when I short the ignition relay under the drivers seat it starts in a second.
-I do have to push the key all the way in to, I guess, make contact between the ignition ring(?) that goes over the ignition barrel.
-When I turn the key to the off position the engine doesnt stop if I keep my foot on the brake pedal.
-I cannot use the cruise control
-I am in limp mode.
-The wiring has been tampered with by some goons to install various lights (it used to be a city truck)
-Instead of an auxiliary AC, they have installed a second alternator with a custom welded bracket! (that I can remove) but that has no belt at the moment so that shouldnt be a problem.

Sadly, my icarsoft diagnostic tool is dead, an other one is on the way, so no codes for now. I do have a check engine light on and the ABS ESP lights on. I know those can put you in limp mode and I'll have to check the wires and tone rings, but thats not the main issue for now.

Thanks a bunch to anyone that can be of help, I will definitely dive into part 8 of the repair manual but I thought I'd ask away to the sprinter masterminds here who might think of something simple or somewhere to start looking.



He’s just this guy, you know?
There’s a lot going on here. First think of check is the brake lights. Make sure that the proper bulbs are in place and properly aligned. A short in the brake lights will cause the engine to run after the keyed ignition is switched off. After that’s been sorted out, some of your problems may be resolved and you can move on to the harder tasks


Engineer In Residence
Most of the issues you describe are probably wiring faults from previous hack jobs. Look at the wiring diagram for the starter, The ECM, ignition switch, and a relay under the seat are all required for the motor to spin up.

Get a good scanner and scan for codes. Wiring faults are very difficult to track down without this diagnostic information. You could have a couple simple fixes, especially the lights, and be back on the road.


Active member
Sounds like you’ve got power or ground back feeding from somewhere into the lighting circuit which is making its way to the ignition. Commonly it’s from the taillight electrical assemblies. I’d unplug them both and see if it’s fixes it. If not, I’d personally start unplugging or removing aftermarket lighting/2nd alternator. If you want to remove it all anyways then I’d just take it all out and start there.


Well-known member
The wrenches are simply a warning that it needs service. You manually 'clear' that through a forgettable process of buttons.
The won't turn off issue is familiar to me. In messing with wiring, I managed to feed power into the ignition circuit causing no shut off. Being related to the brake means that the brake light is feeding into the ignition line, bad wiring. Check the tail lights for corrosion.
So there indeed was a short in the rear lights, that has been solved. The van now shuts off properly. I still get the no start condition unless I short the starter. I will then proceed to disconnect all the aftermarket stuff and see what happens. I am seeing hack wire going straight into the ECM so I am a little scared.


He’s just this guy, you know?
I would suspect the ignition switch as a culprit for your no start situation. With regards to the cruise control, there are a number of ABS/stability control faults that can cause the ECM to disable cruise. When I first got my 2006 if I would bump the cruise stalk it would short out the ECM and blow fuse 15 or 16, causing everything to cut out. Happened the first time about 2 hours after purchase, and I was lucky enough to stumble upon this forum. I had an internal short in the main wiring harness, right behind the fuel filter. It may be beneficial to carefully cut open the sheath over the harness and inspect


Well-known member
One thing comes to mind. Maybe someone put in a kill switch. Maybe the system doesn't know the transmission is not in drive?
Do you think the ignition switch is defective? Some issues with turning. Sometimes you have to wiggle the steering wheel to get it to unlock/turn.


Erratic Member
As ECU wrote, the "two wrenches" are merely a reminder that service is due (either by miles or time).
One wrench is at 10,000 mile intervals (oil and filter change)
Two wrenchs are thrice that (i.e. 30,000 miles) and add fuel, air and cabin filters to the change list.
In the owner's manuals, those are "service A" and "service B".
The wrenches can be cleared by skillful pressing of the dash buttons.
(which i can't find at the moment...)

When you turn on your key, the dashboard mileage indicator will display the mileage (or days if a "d" appears) overdue.
Then it reverts to the usual odometer readout.



Active member
Resetting ASSYST:

Switch on the ignition and immediately press the mi/km selector button twice in quick succession.
Turn the key back to position 0 within ten seconds.
Press and hold the mi/km selector button.
Switch on the ignition again and keep the mi/km button pressed.
An audible signal sounds after 10 seconds and the service indicator is now reset
I just did the reset which worked and put be back to 15 000 km but it only removed the small wrench and the large one is still there, is that how its supposed to go?


Active member
IIRC, the one wrench showing will be on to tell you that is what you are looking at, but after a few seconds it will flip back to the regular odometer, and the wrenches will disappear.
🤦‍♂️ thanks a bunch, so that can be considered solved too!

I should be receiving my scanner soon so I can start getting some codes. In the meantime, how can I check if if it my ignition barrel or connections that are bad? The wires dont seem to have been tampered with, how can I tell if the barrel is bad? Cheers!

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