2004 T1N Rough start, stalls when brake pedal is touched

VIN WD2PD744145634059

Hello.

2004 T1N, approximately 250k.

Began having intermittent stalling while driving on the highway- never found the cause. Slowly progressed, finally parked it. It's been sitting for about 9 months.

I've replaced:
1. The turn signal stalk
2. The steering column Fuse box
3. The brake light switch
4. The ABS module (NOT the motor)

The fault presents as:

1. Turn ignition power on
2.Dash lights blink sporadically
3.Beeper beeps sporadically
4. Start engine, engine runs rough
5. The slightest tough of the brake pedal stalls the engine.
THEN, it goes dead. No power AT ALL, even to the odometer. No fault code on the reader (ISoft).

That was today, 23 March 19.

The brake light bulbs are NOT LED.
I can't find any obvious broken wires.
Battery Voltage is 12.64 volts.
Terminals are clean and greased, including the firewall ground hub.
No fuses burnt out; no obvious loose relays.
No change when disconnecting the MAP sensor.

I've kept it on a trickle charger to avoid the ECM failing.

I'm wondering if the battery is bad anyway.
Meanwhile, I'll await your feedback before dropping the $200 on a new battery, given how much I've already spent trying to chase this gremlin.

Battery wiring? Grounds? Ignition switch? What about the engine ground strap?

Sure sounds like a significant wiring fault (i'd start at the bend just behind the fuel filter)

The "when i step on the brakes" could also be the harness that runs under the Sprinter from nose to tail.

There was a recent (3 months ago?) thread with photos by billfromtomahawk who had a porcupine chew on that under-van cable with produced many strange symptoms.
https://sprinter-source.com/forum/showthread.php?t=67781

--dick

Grounds all have conductivity.

Ignition switch? Battery?

I'll check the harness underneath.

Sounds like "swing test until resolution"....

You checked ALL the grounds? There are a number of them all over the Sprinter. The Service Manual wiring section is the place to look to find all of them.
If you brought your van to my shop, I would start by unplugging one fuse at a time from the fuseboxes and see if I couldn't get the issues to resolve themselves. If that works, you've found the circuit at fault. Then trace every wire in that circuit until you find the offender.

When the gauge cluster goes completely dead break out your multi meter and the wiring diagrams and trace the power supply to the cluster backwards to the battery. At some point you will find where the break in the circuit is. I would guess the ignition switch but it could also be related to a ground or main harness connector.

Sprinter Mechanic- that (fuse check) is a great idea. Will do. And I'll recheck the grounds, as well.

Just ordered a new ignition switch....

odysseus said:

Just ordered a new ignition switch....

Click to expand...

Be great if you posted a picture of the old one.
If it's bad maybe crack it.
I think every vehicle I ever owned suffered a bad ignition switch.
I have gotten fairly good at disassembling them(sometimes in a plastic bag) and rebuilding/cleaning the contacts.

bill in tomahawk

I experienced IC flickering / engine cut out when my ignition switch failed.

So, it got to the point where it quit running altogether. Turning the key produced NOTHING. Battery fully charged. Headlights would work, but no instrument panel action at all.

Turns out, it was the ignition switch.
I odered a new one off ebay, removed the wheel and fusebox, unplugged the old switch, popped it out of the socket, and inserted the new one.

Reinstalled everything, reconnected the battery, and...

Presto. Fired up perfectly.

Thank you all for your help.