Hello, My name isXXXXX am a Certified Auto Technician with 25+ years experience. I will do my best to assist you. I don't know your automotive experience level, so I may have to ask questions of you before I can answer. I only know as much about your concern as you have stated in your post, so please feel free to add as much detailed information as possible.
I had a winnebago with this problem in the past... Does your Winnebago have a "slideout" room?
The easiest way to determine if there is excessive draw is with a Multimeter that is capable of reading amperage up to 10 amps. Do you have access to a multimeter? I can help you determine if the problem is related to the Factory Chassis, or the Conversion Add on's.
You said that it was an '08, when did you purchase it? Do you have remaining basic warranty? If you Post the last nine digits of the VIN, I can check your warranty coverage... Maybe you have some warranty left.
I'm sorry, but I understand how to find out if there is a draw on the battery when everything is turned off, but since this is such a common problem on the Sprinter I was hoping that you or someone on the staff would be familiar with the solution or at least the cause of the problem.
I do have a full 7 year 75,000 miles warranty on both the chassis and conversion, but the nature of the problem is such that I want to know what it is so I can ask them to fix it under the warranty. The best I've gotten from any of the shops is "yes, that is common" or "you must be leaving something on." While I'd be willing to pay $15 for your time, at this point the answer really didn't help.
There is more than one thing that can cause this problem, that's why I have to ask questions of you before I can come up with some sort of solid answer.. It has been somewhat of a common occurance on Sprinters that have aftermarket components installed, and it is not the same root cause every time. On Winnebagos with Slide outs, it has been common to find that the Slide Out controller module is responsible for an excessive draw. Winnebago said that this was normal, but a 70 to 80 milliamp draw is too much. Factory states that 35 milliamps is the max allowable ignition off draw...
So that's why I wanted you to test the Draw, to see how much it is, then we can do a process of elimination to see if the problem is in the Conversion side of the electrical system or the Sprinter Chassis side of the electrical system....That way, you will know who to take it to for the warranty repair. Because, if it is the conversion, it needs to be taken to Winnebago.
I have also seen problems with the fusible link wire from the alternator to the Battery, there is problems with the fuse link going bad and causing exess resistance, and due to this, the battery never gets fully charged. and can cause it to go dead in a few days...
So if you want to continue we can do so, and you can "Accept" whenever you are ready, this process may take a few days. it is up to you...
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