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duckdave · 03-10-2018, 02:52 PM

This is in a 2006 Airstream (Parkway) Interstate (T1N). Vehicle model year 2006; Airstream model year 2007 (pretty sure). So an early model AS Interstate.

Backstory: I was trying to access my headlight chamber via the engine compartment. It seems both low beam headlamps are out (this fact is unrelated to my question, I think). As I was looking around in there, I noticed a loose red cable over near the engine battery. See picture, loose wire is all the way to the right.

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I was not familiar with the power distribution center arrangement pictured, but I noted one position was vacant—position #4. Fortunately, I stumbled across a diagram about the Power Distribution Center (PDC) over on Sprinter-Forum here

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According to the PDC diagram, position #4 is for an Independent rear A/C unit.

Now, I don't think my Interstate A/C unit in the rear was installed by Dodge (Mercedes) on manufacture. That would likely seem something done by Airstream during the conversion into an Interstate thing. Not sure, but guessing—not. I do know that the A/C unit was replaced by the previous owner. Come to think about it—that A/C runs on 120VAC, so it wouldn't be powered by a 12VDC cable.

Gosh, these things are so danged complicated...did the original AC run on 12V? Naw!

So does anyone know, or have any guesses about, what this disconnected cable is? Suggestions about how to figure this out also welcomed.

Titus · 03-10-2018, 06:55 PM

I don't know anything about it, but here are my two cents worth.

It seems odd for Mercedes to pre-wire all Sprinters for a rear AC when (I would think) few of the Sprinters actually have one. I think that a rear AC would use refrigerant from the engine-driven compressor. So the only electricity needed for the rear AC would be to power the fan. And the 12V wire looks larger than that needed to power a fan. I think you are correct that the Interstate never had a rear AC - other than the 120V one on the roof.

Titus · 03-10-2018, 06:57 PM

More likely, I think, is a wire of that size for a rear window defroster. But that is not consistent with what you found in the PDC schematic.

Boxster1971 · 03-10-2018, 07:51 PM

I'm not that familiar with the older Interstates on the T1N Sprinters, but that wire looks a lot like the cable on my 2013 Interstate that connects to the battery isolator relay to charge the house batteries when driving.

It would have been added by either Airstream or a subsequent owner.

duckdave · 03-10-2018, 08:38 PM

Titus: I would agree with you on both points. 1. No rear window defroster. 2. Seems weird that Mercedes would prewire for a rear AC.

Boxster1971: I would love for there to be a way to charge house batts while driving. That cable size is large. Might it be something that was connected only as needed?

We will be doing some National Park camping out in Utah in Sep-Oct. my experience w/ N/P on east coast is they are often "dry" with regards to electricity, etc. A way to recharge house batts while driving, off alternator, would be great. How would I figure this out?

InterBlog · 03-11-2018, 06:45 AM

Quote:

Originally Posted by duckdave

...A way to recharge house batts while driving, off alternator, would be great. How would I figure this out?

That capacity should already be present in your rig. To my knowledge, all T1Ns were designed that way. Although I will say that the original set-up in our rig was so pathetic that the OEM alternator barely delivered any charge at all, so you might not have noticed it occurring.

I'll ask my husband LB_3 to look at your pics. He worked extensively with the original system before we upgraded to lithium.

Titus · 03-11-2018, 07:16 AM

Boxster raises a good point - maybe Airstream used the Mercedes 'rear AC' cable as the cable to the Battery Isolation Manager (BIM) to provide alternator charging to the coach batteries or Magnum (in my case, Tripplit in yours) charging to the chassis battery. No clue as to why your BIM cable would be disconnected. It is a nice feature to have - even though the BIM Airstream uses is not ideal.

LB_3 · 03-11-2018, 08:36 AM

I assume Airstream connected it to the BIM as well. I would recommend getting a tone generator (wire tracer) from one of the big box stores and then going on a scavenger hunt under the driver’s seat.

duckdave · 03-11-2018, 10:00 AM

Thanks everyone for your thoughtful suggestions. These give me several directions to pursue, whereas before I hadn't a clue.

Quote:

Originally Posted by Titus

Boxster raises a good point - maybe Airstream used the Mercedes 'rear AC' cable as the cable to the Battery Isolation Manager (BIM) to provide alternator charging to the coach batteries or Magnum (in my case, Tripplit in yours) charging to the chassis battery. No clue as to why your BIM cable would be disconnected. It is a nice feature to have - even though the BIM Airstream uses is not ideal.

AFAIK, my coach battery is not charged off the engine alternator, but I sure could be wrong. I've noted you guys talking about the BIM, but I assumed I did not have one, possibly since we don't have solar (yet?). Generally, where would one look for that, under drivers seat?

Titus, I don't understand what you're referring to with terms "Magnum" and "Tripplit" yet, but hopefully google will help me out.

One (possibly) weird thing about our ASI is the location of the coach battery. It's under chassis behind driver's-side rear wheel. The ASI owners manual says that batt should be under passenger seat. There is a battery platform there,but it looks new, and no apparent cables.

Finally, LB_3, could you suggest a brand for your suggested "tone generator (wire tracer)". Normally, I would think Craftsman for items like this, but our local Sears closed, and I think the quality of their stuff has deteriorated. I was recently looking at their digital clamp-on ammeter, thinking I might need one of them for this job, but the reviews were very spotty. But I always enjoy the side-effect of DIY—Oh, boy! More toys!!!

Boxster1971 · 03-11-2018, 12:18 PM

I think the house battery was under the passenger seat on older T1N Interstates. It’s possible the previous owner relocated the battery behind the rear wheel and thus disconnected the cable to charge the house battery in the original location. If that is the case you will have to run a new cable to the new battery location in rear of van.

Good luck and enjoy the new toys.

Titus · 03-11-2018, 02:21 PM

The pre-2012-13ish Interstates had a Tripplite invertor/charger and those after have Magnum. Magnum is preferred, to the extent that some owners even go to the expense to change from Tripplite to Magnum. This is the charger for the coach (Airstream) batteries, and the BIM allows the Tripplite/Magnum to also charge the chassis (Sprinter) battery. The BIM and solar charger are completely separate, though Airstream may have introduced both at the same time. My BIM (and other electrics such as Magnum, solar controller, etc.) is under the rear lounge seat, but I have no idea where yours might be. It is a pain to get to (have to remove the rear seat), but better (IMHO) than trying to work in the small space under the driver or passenger seat.

If you like tinkering then the AI is the thing for you. I am recently retired and it keeps me as busy as I want to be. It works as-is, but there are many opportunities to improve things (or at least to change things).

duckdave · 03-11-2018, 04:08 PM

Thanks for the replies all.

So the model year thing is confusing, as InterBlog as pointed out in the past. Ours is a 2006 model year Dodge Sprinter/2007 model year AS Interstate.

We are the second owners. The original owner is a member of our Arkansas Razorbacks Airstream Club, so we see him at club events. But he's even older than me, so sometimes it's difficult to get information from him. I'll have to press him as to whether the battery was originally located under the passenger seat. I do know that the rear location did not look like a professional install...AT ALL! I got the PO to admit modifying the opening with a Sawzall to facilitate battery removal, but he did not remember every having a cover for the rear battery area! See Need some suggestions re Battery Box in '06 Interstate. So anything is possible, even likely!

Our ASI originally had the Magnatek/Parallex 7355 converter charger in it. The one AS has been using for years that's killed off so many batteries, including the one that came with ours. I recently replaced it with a Progressive Dynamics PD4655VL converter/charger (multistage) and Lifeline GPL27T AGM battery. Our converter/charger is located below the closet in the 19" walkway near the floor. I've be admiring the posts of InterBlog/LB_3 describing the installation of their Li system in the same location (actually, much deeper into the cabinet). My install only took a couple of hours, and could have been done much faster by an experienced installer.

So, I too am recently retired, last July. Somewhere on this forum I read a sig line that said something along the line of, "I'm glad I retired so I could work full time on my RV." I'll have to keep an eye out for that line so I can credit the original source.

xrvr · 03-11-2018, 04:52 PM

Quote:

Originally Posted by Boxster1971

I think the house battery was under the passenger seat on older T1N Interstates. It’s possible the previous owner relocated the battery behind the rear wheel and thus disconnected the cable to charge the house battery in the original location. If that is the case you will have to run a new cable to the new battery location in rear of van.

Good luck and enjoy the new toys.

Correct info!

duckdave · 03-12-2018, 10:16 AM

I found some info about Battery Isolation Managers. So, I'll start looking for something like this.

This circuit includes a dash switch so you can start your engine from the coach battery. I've looked pretty hard for such a switch and have not been able to find one yet.

LB_3 · 03-12-2018, 12:07 PM

Quote:

Originally Posted by duckdave

I found some info about Battery Isolation Managers. So, I'll start looking for something like this.

This circuit includes a dash switch so you can start your engine from the coach battery. I've looked pretty hard for such a switch and have not been able to find one yet.

that is one of the Airstream battery relays. You’re looking for a Mercedes relay. I’ll post a pic in a couple minutes.

LB_3 · 03-12-2018, 12:13 PM

This is on our 2006 Sprinter / 2007 Interstate:

It’s at the back of the driver’s seat.

duckdave · 03-12-2018, 07:54 PM

LD_3: So you—like—have to remove the drivers seat to find this part?

Note to self: you worked for a auto glass/upholstery shop in college... you know how to take out car seats! No problemo!!!

BTW, many, many thanks for your post! At least I have something to look for...

Like I said before, these are complicated beasts!

xrvr · 03-13-2018, 04:45 AM

Move the seat as far fkrward as possible. Mjght work.

Titus · 03-13-2018, 05:00 AM

DuckDave

The picture of the BIM that you linked to is the one that I have in mine. It does support the use of a battery-combiner switch near the bottom left of the dashboard, but I imagine that it would also work to charge batteries in both directions even if you did not have the combiner switch. But based upon the LB3 picture your earlier model might have a different one - if it has one at all after the modifications made by the original owner.

LB_3 · 03-13-2018, 07:41 AM

You can slide the seat cushion off by releasing a lever under the front lip of the seat and sliding the cushion all the way forward. It’s tight and may take a little force. There is a cardboard cover at the top of the pedestal that is held in place by 4 torx screws. You will have to slide the seat forward/backwards to access those screws.