fuse or breaker for dash radio?

[Keith Oliver]

My "new to me" coach has a good dash radio.  We have enjoyed CDs through it while parked, especially the good surround sound system.  When I had a tech install the brake controller for the tow dolly, the tech stole power, ground and brake signal from connections on the front of the wall in the generator bay.  Following that installation, the radio no longer lights up.  I presume a blown fuse.  I called the tech, who stated that there should be an in-line glass fuse behind the radio.

In searching for a blown fuse, I removed the radio from the dash (easy, using a slim allan wrench to un-click each of 4 connectors in holes on the sides of the bezel), pulled out all the unused extra wiring and both visually and by reaching way inside, searched the cavity for a fuse, with no luck.  I have also checked all of the marked fuses in the LF electrical bay and in the back closet, also without finding any.
This coach, while not technically a Beaver (2007 Monaco Dynasty 43, King III), is in most respects, a Patriot Thunder.  Gerald and Glenda have assured me I can continue to mine this forum for its storehouse of knowledge, since I have cut my teeth on a true Beaver and "once a Beaver, always a Beaver".

 Do any PT owners know the whereabouts of a fuse or breaker for this radio?

[Joel Ashley]

Keith, I presume your headlight switch isn't rotated fully clockwise?  But you probably would have noticed other dash lamps dimmed.

My diagram doesn't show a fuse in-line;  just circuit breaker 68 in the bay, which may be a different CBr # on your coach.

Joel

[Keith Oliver]

Joel
Thanks for your input.  Not just that the light isn't coming on, the whole radio is not functional.  The dimmer has been rotated since the radio stopped working.

On your breaker panel, are the breakers identified other than by number, as mine are labelled with the function (mostly abbreviated, so some understanding is required to get the right interpretation) rather than by number?  If so, what other functions are represented in the section in which your #68 is located?  Most of mine are automotive style fuses, not glass, but the more modern two prong style.  All fuses and breakers have function labels, not numbers.

[Joel Ashley]

Sorry Keith, when you said it didn't light up, I presumed it was just the illumination.

My electrical bay breakers are not marked, but there's a legend on the inside of the bay door.  I took a photo of it when the rig was new and made copies for my schematic book, coach service files, and owners manual.  Even though the one on the door is fading as expected, I have handy other references.

CB68 is in the middle of the far left breaker buss, with CB66 and CB67 as a threesome.  68 is the lower one.  They are fed by their own heavy red lead and 66 & 67 are HWH related breakers.  Yours is a different year and model than mine and the breakers may be differently oriented.  I haven't seen too many spade or glass fuses in my rig, at least not relating to the chassis side.  But if your breakers are functionally marked, you should be able to ID the radio one.  I'd start by checking that breaker for 12v on both sides.  My diagram shows no other breakers or fuses associated with the radio.

There are only 4 power-related wires out of my radio, which may be a different model than yours ... Ignition accessory side is red;  battery via circuit breaker 68 is yellow;  the headlight switch dimmer lead is orange;  and the ground to the electrical bay ground buss is black.  Those colors are out of the radio, but likely connect to regular Monaco labeled white wires along the way.  Check that the ground buss' screws are all solid.

On car radios I've always found in-line glass fuses behind the dash not far from the unit - same with CB and Marine band radios, but I'm an old scudder.  If there's anything back there it's not diagramed and is more likely an in-line spade fuse these days.  I'd expect the circuit breaker to be adequate though.  Check for 12v at the yellow wire, and the red when the ignition is on.  Check the black for continuous ground.

Don't know if any of this will be of any help.  Did your tech do anything with the ignition accessory switch?  Don't know what's related to the generator wall that the tech could have done to affect the radio.  The only firewall breach shown on my diagram is for what appears to be roof runs to speakers.  :-/

Joel

[Keith Oliver]

Joel
Thanks again for your thoughts.  One of the mysteries that you have helped with is the colour coding of the wires.  Now, if I can't find the breaker, i can do as Gerald suggested, and run a new power wire to the electrical bay and tap into a good circuit.
And no, the tech didn't get near the ignition accessory switch.  This radio was lighted and operational at all times. It wasn't through the ignition.
I am away from the coach and its documents for a few days, but will get back to you when I have applied this new knowledge.

thanks,
Keith

[Joel Ashley]

This presumes that most if not all dash radios use the same wire designations.  Ours is a Visteon radio/6 CD changer.

You might check for an installation manual, or at least a wiring diagram of your model, online at your radio manufacturer's website.

Joel

[Stan Simpson]

Our manual says the radio is a Visteon 6 CD changer. But its really a Ford radio from a 1995 Explorer and others.

Stan

[Steven Hoffman]

Our coach is older but has a "Stereo Power" switch on the wooden console in the center of the dash.  I don't know if there is anything like that on the newer coaches?

Steve

[Joe Van Loan]

As Joel mentioned most dash radios have three power leads -- One to battery to keep memory alive when not powered on, another to the ignition ACC position to turn the radio on and off with the key and one to the dash lamp circuit to illuminate the radio when the head lights are in use.  I believe both leads must have power for the radio to operate
It sounds like you might have a Ford radio  as indicated they the retaining method used.  
If you have access to the back of the radio you should check to see if there is power to either the Battery lead or the ACC lead.  If it is a Ford radio there should be a connector on the back of the radio where you should be able to probe with a meter lead.  Be sure the ignition switch is in either ACC or ON for this test.

The ACC circuit on the ignition switch should also provide power to other devices such as the heater blower.  All those devices would share a common fuse, so you would notice other devices not working in the ACC position.  For that reason, the failure is likely in the Battery circuit.  When you refer to the LF bay, I assume that is the bay beneath the driver's seat that is accessible from outside the coach.  The fuse for the Battery lead on the radio should be located in that bay.  It might be shared with other devices in the coach.

Electric trailer brakes draw considerable more current than the radio so if the brake controller installer connected the brake controller to the radio lead, the fuse would likely blow on the first application of the brakes.  If that happened he might have moved on to fine a higher current source for the controller leaving the radio fuse blown.
It is doubtful that there is a fuse somewhere in the wire leading to the radio.  That practice went out many years ago. So that fuse should be in the front bay.

Did you say you have schematic diagrams of the coach electrical systems?  If so, the power circuit for the radio should be shown on one of the drawings.

[Joe Van Loan]

As Joel mentioned most dash radios have three power leads -- One to battery to keep memory alive when not powered on, another to the ignition ACC position to turn the radio on and off with the key and one to the dash lamp circuit to illuminate the radio when the head lights are in use.
It sounds like you might have a Ford radio  as indicated they the retaining method used.  
If you have access to the back of the radio you should check to see if there is power to either the Battery lead or the ACC lead.  If it is a Ford radio there should be a connector on the back of the radio where you should be able to probe with a meter lead.  Be sure the ignition switch is in either ACC or ON for this test.

The ACC circuit on the ignition switch should also provide power to other devices such as the heater blower.  All those devices would share a common fuse, so you would notice other devices not working in the ACC position.  For that reason, the failure is likely in the Battery circuit.  When you refer to the LF bay, I assume that is the bay beneath the driver's seat that is accessible from outside the coach.  The fuse for the Battery lead on the radio should be located in that bay.  It might be shared with other devices in the coach.

Electric trailer brakes draw considerable more current than the radio so if the brake controller installer connected the brake controller to the radio lead, the fuse would likely blow on the first application of the brakes.  If that happened he might have moved on to fine a higher current source for the controller leaving the radio fuse blown.
It is doubtful that there is a fuse somewhere in the wire leading to the radio.  That practice went out many years ago. So that fuse should be in the front bay.

Did you say you have schematic diagrams of the coach electrical systems?  If so, the power circuit for the radio should be shown on one of the drawings.

[Keith Oliver]

Joe:
Thanks for pitching in.  I watched the tech do the installation.  There was no hesitation, no false starts.  He used a lighted probe to find power and attached the brake controller to the first powered spot he found.  No fuse there blew as the brake controller worked properly all the way home, while the radio stayed silent and dark.  I will be back to the coach tomorrow,so I should be able to put into practice all the suggestions presented above.  I'll let you know how that goes.
I have looked through the schematics, but haven't seen any reference to the radio.  That would be too easy.