2006 SMB (Ford) RB50, Ford factory radio / CD player

My radio recently stopped playing music. But only when it should be powered by the VAN battery. When I activate the "Extra Battery" switch, it turns on and works normally.

When the switch is off, the radio will not turn on. I can get it to display the clock when I press the "CD EJECT" button, but then it turns back off. It's not losing its presets or time, so I know the continuous power is working.
The 5A "Radio" fuse in the fuse block is intact.

Anybody got an idea what might be wrong?

I haven't pulled the radio to look at the "Extra battery" relay for loose wires. I'll probably do that tomorrow.

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2006 E350 Diesel, SMB 4x4, RB50- "Hopper"- SOLD

That switch is evil. Remove it and restore the factory van wiring.

On my van, when switched to the HOUSE battery, it caused a drain on the VAN battery.

No idea what your problem is, but it will be something to do with the switch.

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Sportsmobile-less.

"A job worth doing is worth doing at least twice."

Did you find the problem? There might be another fuse (non factory) you're missing. Some radios use a separate power source for the display that has nothing to do with the main radio. The radio switch activates a relay so I'd also be looking there. Part of my stereo system runs off the house battery system when the radio switch is in the on position but whether or not that switch is on or off, the amps run off the starting batteries. Those amps pull a reasonable amount of amperage so the problem most people have is if you leave the radio switch on, it can drain both battery systems down even with the ignition off.

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2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures

I am going off a 2004, but there should be 4 fused power circuits going to the radio; F2.22 (15A) hot at all times, F2.3 (15A) hot in run or Acc, F2.27 (5A) hot in start, and F2.36 (5A) hot in park or headlights. From your symptoms it sounds like F2.3 is blown or there is a problem with that circuit.
In the SMB radio switch the F2.3 circuit (yellow/black) is cut and diverted to the normally closed (87a) contact of a SPDT relay. The SMB radio circuit (15 A from the SMB fuse panel) then goes to the normally open contact (87), it will most likely also go (86) the "+" side of the coil. The common contact (30) will then go back to the radio side of the f2.3 circuit. You should then have a ground going to a SPST switch with the output going to (85) the "-" side of the coil. You probably also have a LE with the anode connected to (86) and the cathode connected to 85. In normal operation the switch is open, the relay remains in the normally closed position so the f2.3 circuit operates as normal, when the key is in Run or Acc there is power to the radio and it starts up. When the key is off, there is no power to that radio circuit, so the radio does not come on. The memory circuits are usually powered off of the always on circuit F2.22 Red/White. When you turn the switch on you now complete the ground circuit to the coil of the relay, this energizes the relay switch to the normally open side of the relay, now the 12 volt power is supplied from the SMB (15A) circuit, the cathode side of the LED is now also grounded indicating that the relay is energized. Even with the switch in this position there will be some minimum draw of the illumination circuit F2.36, also some radios will take advantage of the fact that the always hot circuit is 15 amps and internally turn on circuits that are powered of this input causing more than the traditional expected draw from just the memory circuits. if you want to eliminate draw off of the van battery you need to also move F2.22 to the house battery. There would still remain some possible minimal drain because of the illumination circuit. F2.36
Hope this helps, it would be possible that wiring to the coil is not exactly like this, a coil does not have any polarity so reversing 85 and 86 would not be a problem, they could also switch the 12 volt side of the coil instead of ground. It is generally good practice to use 86 as the "+" side and 85 as the "-", but not a requirement.

-greg

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-greg
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"Goldilocks" 2020 Ford Transit High Roof Extended 3.5 EcoBoost AWD Homebuilt

Not until I read Scalf77's post (Thanks!) I just went out and checked and the F2.3 was blown. I missed that that one had anything to do with the radio when I read the owners manual looking for radio fuses.

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2006 E350 Diesel, SMB 4x4, RB50- "Hopper"- SOLD

I am planning on wiring a similar switch in my rig during my home build so thanks Scalf77 for the detailed wiring description!

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2008 E350 RB passenger 4WD SMB penthouse
2013 KTM 350 EXC
2008 KTM 250 XCF-W
2003 Honda Element

I have added a diagram of the Radio Switch to Wiki
http://www.sportsmobileforum.com/med...e_Radio_Switch

=greg

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-greg
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"Goldilocks" 2020 Ford Transit High Roof Extended 3.5 EcoBoost AWD Homebuilt

Cool.....even better......really appreciated.

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2008 E350 RB passenger 4WD SMB penthouse
2013 KTM 350 EXC
2008 KTM 250 XCF-W
2003 Honda Element

DOes the "radio switch" allow you to choose between house battery power and van-battery? Do you need the key turned to tell the stereo to activate? thanks

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Joe Skrivan
E-350 V-10; Penthouse, Custom Interior

On mine if the key is off the radio works with the rear radio switch on.

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2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures