Mystery Switch

[campIV]

Does anyone know what this switch is for? It’s a three position switch to the left of the water pump switch. All three terminals have a wire attached. The red wire is +12vdc. All three wires run through the cabinet below the stove and disappear behind the fridge. I haven’t found anything that changing the position of the switch affects and there’s no information about it in the original manual that came with the van.

I’m thinking of pulling the wires off the switch and insulating them because I’m uncomfortable with having a possible short circuit develop somewhere. Any input would be greatly appreciated.

Van info:
1997 Sportsmobile, Ford E250, RB50, manual pop-top, 5.4L, 2WD, propane stove and furnace, 12/120 fridge, electric water pump. No water heater or inverter.

Please note that for some reason the first picture posted upside down so the switch in question appears on the right.

Thanks again,
Fritz

[Steve C]

That 3-way rocker has me somewhat puzzled. My 2001 has a 2-way in the same spot and it's used as an override for the AM/FM radio so the radio can be listened to without having to have the ignition key in the ACC mode. Maybe yours is wired to use either the starting battery or house battery? I'd test by having the radio on, turn the ignition key to off and seeing if the radio turns on when you play with the switch. Otherwise... best of luck.

[campIV]

Originally Posted by Steve C

That 3-way rocker has me somewhat puzzled. My 2001 has a 2-way in the same spot and it's used as an override for the AM/FM radio so the radio can be listened to without having to have the ignition key in the ACC mode. Maybe yours is wired to use either the starting battery or house battery? I'd test by having the radio on, turn the ignition key to off and seeing if the radio turns on when you play with the switch. Otherwise... best of luck.

Steve, thank you. I tried what you suggested and tho the radio doesn’t stay on without the ignition in the accessory position, when I flip the switch with the radio on it dims the display for some reason. As if the headlights were turned on.

The radio had been replaced more than once before I bought the van. I replaced it about a year ago after the previous unit died because of a short inside the dashboard. Smoke coming out and everything!

I’ll dig into the wiring further now that I have an idea what the switch is probably for. If I can’t solve that puzzle I’ll just pull and insulate the wires to be on the safe side.

Thanks again for your help!

[REF]

That’s weird about dimming the display, and I agree, it was most likely the stereo switch that ran it from either starting battery or house battery. I can’t remember if I had a 2-way or 3-way switch, but the center position is most likely an off.
Keep in mind it takes a minute for the stereo to kick on if you are toggling the switch and expect immediate results, but in at least one of the positions, the stereo would not kick on if the van is not running and not in ACC mode.

[ShuttlePilot]

On my 2005 there is a three way switch. The original owner replaced the original unit twice by "stereo shops" before I bought the van. When I brought it home and I replaced all the absolutely dead batteries I realized there was a cross connection between the house battery and starter batteries somewhere. Turned out the clowns that installed the last system powered the head unit in the dash with the house battery and still used this switch/acc in the dash circuit to turn the amp and head unit on. This created a cross connection somewhere within the head unit or amp causing strange charge/discharge behaviors. Amazingly it didn't put the smoke out. In the end I kept the entire infotainment system powered by the house battery but added an isolation relay to the turn on leads.

Anyway, that's my wordy story of, that switch is probably your stereo on selector, I agree you probably need to look again at the whole wiring set up. I would guess that you have power to the night/headlights on lead at your head unit which is why the display dims at times.

Sounds like you are on top of it but I wanted to reinforce your confidence.

- Eric

[86Scotty]

I'm going with stereo switch as well. I would recommend installing a fighter jet style ejection seat in the passenger location and wiring it to that switch. After a few cocktails with your significant other it could be fun to flip the switch. Please report back.

[daveb]

With my stereo system I have two amps, one regular amp up front and another for a sub woofer amp at the rear of the van. That bass amp draws quite a bit of power and is not really necessary if I'm camped and using the stereo system as a surround sound for my video. I had SMB put the switch on it to cut out the bass amp. Perhaps it was to let you select if you want to use a second amplifier???

[Twoxentrix]

Personally, I haven't found the need to use my Vans stereo system once while parked (Other than flipping the rocker switch several times over the years just to confirm it works).
With the amount of songs/albums our phones are capable of storing these days, along with the quality (and convenience) of wireless speakers, it just seems pointless.
We use our Ultimate Ears MEGABOOM 3's both inside and out; can strategically place them anywhere in our campsite, river/lake, with us while on the tubes or Bikes, etc - can't do any of that with the van stereo.

[Charliesmom]

Do you have outside lights? SMB installed a three-way switch identical to yours that turns on an outside light on the passenger side of the van. White => Off => Amber

[Scalf77]

I also would think it is for the radio. Generally SMB has used two methods, a straight SPDT switch.



or with a SPDT relay




Both of these SMB mods interrupt the voltage that is supplied in Accessory or Run circuit with a switch or relay.

The benefit of the relay is that you can add the indicator lamp.

The other three power inputs to the radio connector are the always power (15-amp) voltage supplied in start (5-amp), and illumination (5-amp)

-greg