Mystery Switches (sort of), Thoughts?

[jdbfreeheel]

All,
Newbie here. Picked up our new-to-us 1997 SMB EB E350 2wd this past weekend and took it on a shakeout trip. Generally, things went well but we're still chasing a few electrical/switch/av mysteries.

I've searched a bunch on the forum and have read about battery switches (van v house), etc. However, I'm not quite sure about the following.

1) The switch below appears to not be original but is located on the same panel as the rear vent/fan knob and the thermostat. It is a toggle switch with 3 positions (depressed on left, neutral at center, and depressed at right). Written in pencil above the switch is "F" on the left and "R" on the right. Assuming that these stand for "Front" and "Rear," I'm trying to determine what exactly this switch does. After a little investigation, I've noticed that with the key out of the ignition and with no shore power connected, if the switch is on "R" the stereo in the dash turns on. If I turn the switch to neutral or "F," the radio shuts off. All other lights, rear fan, etc seem t work with the switch in any position. Ok, so that maybe means it's an ignition bypass? So, does "R" mean that the "rear" or house battery is being used for the stereo? Hmmmm. See below for a picture.



2) Second is a set of coax cables that run through a junction switch which terminates in a single coax that goes to the tv in the back of the tv cabinet (a fantastic 9 inch tv/vcr!). So, I know that there's an external coax hook up on the rear driver side of the van, but anyone have any idea why there would be two other coax cables necessitating a switch? Maybe from the front dash stereo (an older aftermarket Alpine unit with a slide out touch screen/gps thing), but even still that would be two coax cables. Any ideas?



Many thanks!

Josh

[rionapo]

Your sound system allows you to run the stereo off the rear (camper) battery when the engine is off?

[jdbfreeheel]

Originally Posted by rionapo

Your sound system allows you to run the stereo off the rear (camper) battery when the engine is off?

Yes, I guess that's correct. So, I'm assuming it's a power selector switch where the "R" standing for rear means that the rear battery is "on" for powering the dash radio. I'm trying to make sure that that is the only function of the switch and that it's consistent with what others have and experience.

Anyone have thoughts on the tri coax switch?

[Scalf77]

You may have the built in TV antenna's. One goes straight into the three way box, the other goes through the booster (that is the silver box in your picture). So the three way switch has cable, ant, boosted ant.

-greg

[jdbfreeheel]

Originally Posted by Scalf77

You may have the built in TV antenna's. One goes straight into the three way box, the other goes through the booster (that is the silver box in your picture). So the three way switch has cable, ant, boosted ant.

-greg

Perhaps, but I think the photo is deceiving, the three cables going into the switch from the bottom all come from the plastic sheath that comes in from the right side. The single cable coming out of the switch wraps around and terminates at the grey box at the bottom with the dc plug.

So, the in-line booster is at the wrong point in the series, as it is set up, it boosts any of the three signals coming through switch.

Other thoughts? Or do I understand the system incorrectly?

[jage]

4 antennas at box- the one going out the top looks like it loops around through the 12v booster, then into the switch plate which I assume is "out" to the TV.

1 of the 3 "in" would be built into your top.
1 would be and RV-part type hookup.
1 would be... uh... hmm.

The switch is probably an early "radio switch", SMB has refined it to an "on" (e.g. house battery) "off" (e.g. starter batt on key). I guess my question is if the van and radio are on, switch in F and you turn it to neutral, does the radio go off?

Either way, I doubt there is more mysterious function than that... unlike the killer 3rd antenna!