Sprinter EIS Protective Boot Modification
Over the past several months I read about several 2019 - 2023 MY Sprinter owners who had issues where the the vehicle wouldn't start (dead)..... or the transmission would be stuck in park.... or various error messages would display on the cluster. In most cases they had to be towed to a Mercedes dealer.
Some people were attributing this to the chassis battery being weak or completely discharged. Its one of the reasons I installed a permanent battery maintainer. But after doing some more research, the real issue was moisture getting into the EIS Module. I found posts on several different forums (Sprinter and RV forums) about this particular issue.
I originally thought the module in question was the ECU under the hood since it is fairly exposed..... but it turns out to be a module under the driver's side kick-panel inside the vehicle. In some rare instances someone had a drink on the dash that they spilled and it ran behind the dash and into the EIS Module shorting it out.
In many other cases it was caused from condensation forming on the windshield and running behind the dash..... especially when sleeping in the vehicle in cooler climates... and especially with window shades installed.
Unfortunately the engineers in Germany never thought about people sleeping in the Sprinter in colder climates where moisture could build up inside the cab..... or people that live in humid places like Florida (not sure the Germans know what a humid climate is.....). As a result they installed the EIS module in a way where moisture can drip directly into the EIS or even run along the wiring and into the connector. At the very least corrosion occurs in the connector causing intermittent issues but in many cases moisture gets into the EIS...... and after a flatbed tow to the MB Dealer and a $2500 repair bill, you have the privilege of driving out of the dealer and being on your way.
There is no recall for this issue since it is not widespread but there is a TSB for applications where moisture could be an issue in the 2019+ Sprinter. Mercedes developed a $20 vinyl boot to go over the EIS Module to prevent moisture from getting into it and they also can loop the wiring harness so moisture running down the wires drips away from the connector.
I read about one guy who paid a Mercedes dealer $150 to install the vinyl boot incorrectly..... such that water would actually collect in it with the EIS module sitting inside the boot!
When I was installing the MidCity Engineering Remote Start / High Idle Kit the other day I was working with the EIS Module and another Control Module that could be subject to the same problem. I decided to be proactive and develop my own solution to protect both modules under the dash on the driver side of the coach.
The first picture is the Mercedes $20 EIS Protective Boot. I found several pictures online along with a few videos of it being installed.
The second thru fifth pictures are the protective covers that I fabricated. The first two are for the EIS Module and the next two are for the second CM. I added grommets like the Mercedes boot so I could use zip ties to secure them in place. The white rubber side faces out where water could hit it and the black felt side faces down towards the modules.
The sixth picture shows the cover in place on the second CM and the last two pictures show the EIS Module covered before and after I installed the kick-panel.
After eyeing everything up after the installation, I think I have protected both modules from water intrusion as best I can.
If you don't do much cold weather camping or live in an extremely humid climate, I doubt you would ever have a moisture problem causing issues with the EIS. But if you do, then this may be something worth exploring to prevent a costly tow and repair.