12 volt RV Stereo Power

[Iron Duke II]

I just purchased a new IRV34 RV stereo to replace the old QX model(there was short in the old stereo speaker controls I was unable to diagnose) in my 2005 Nomad Camper. I disconnected the 12 volt power from the old unit and began the process of connecting power to the new unit. There is 12.5 volts on the connection from the trailer, however when I test the wiring connection between the stereo and the trailer the voltage is 0.7 volts. FYI, the stereo came with a 15A inline fuse on the positive wire. I went back and reconnected the old stereo to see if it was seeing 12 volt power with the same trailer connections and it reads 1.1 volts. I tested the stereos using spare 12 volt battery I keep in the garage on a trickle charger and they both worked. Please adivise.

 

[DonTom]

I just purchased a new IRV34 RV stereo to replace the old QX model(there was short in the old stereo speaker controls I was unable to diagnose) in my 2005 Nomad Camper. I disconnected the 12 volt power from the old unit and began the process of connecting power to the new unit. There is 12.5 volts on the connection from the trailer, however when I test the wiring connection between the stereo and the trailer the voltage is 0.7 volts. FYI, the stereo came with a 15A inline fuse on the positive wire. I went back and reconnected the old stereo to see if it was seeing 12 volt power with the same trailer connections and it reads 1.1 volts. I tested the stereos using spare 12 volt battery I keep in the garage on a trickle charger and they both worked. Please adivise.

Sounds like it could be a corroded wire or poor connection at the connector.

-Don- Reno, NV

 

[Iron Duke II]

Sounds like it could be a corroded wire or poor connection at the connector.

-Don- Reno, NV

Thanks for the reply.
All the wiring is clean. Current at from the 12 volt battery The issue seems to be almost an attenuation effect. The stereo power is simply 12 volt positive wire and ground wire. The power at the two wires coming from the trailer measures ~12.5 volts. however when the trailer power is connected to the stereo at the bare wire connection (where the wires connect) the voltage on the source wires drop to 0.5 volts. I can connect a separate 12 volt battery to the same stereo connection plug and it comes on fine. To try and clarify, the connection going to the stereo works fine and reads 12.5 volts.

 

[DonTom]

Thanks for the reply.
All the wiring is clean. Current at from the 12 volt battery The issue seems to be almost an attenuation effect. The stereo power is simply 12 volt positive wire and ground wire. The power at the two wires coming from the trailer measures ~12.5 volts. however when the trailer power is connected to the stereo at the bare wire connection (where the wires connect) the voltage on the source wires drop to 0.5 volts. I can connect a separate 12 volt battery to the same stereo connection plug and it comes on fine. To try and clarify, the connection going to the stereo works fine and reads 12.5 volts.

The reason for the voltage drop between no load and the load of the stereo can only be one reason. High resistance in the wiring (includes the ground wire & the fuse). That is what makes the voltage drop under load.

The high resistance can only be two reasons. Bad wire or bad connection. There are no other possibilities based on what you have posted here.

BTW, a clean looking insulated wire can be corroded in the inside, especially if it has been exposed to water, wet weather, etc.

-Don- Reno, NV

 

[Iron Duke II]

The reason for the voltage drop between no load and the load of the stereo can only be one reason. High resistance in the wiring (includes the ground wire & the fuse). That is what makes the voltage drop under load.

The high resistance can only be two reasons. Bad wire or bad connection. There are no other possibilities based on what you have posted here.

BTW, a clean looking insulated wire can be corroded in the inside, especially if it has been exposed to water, wet weather, etc.

-Don- Reno, NV

All good guidance. Thanks

 

[DonTom]

All good guidance. Thanks

You have not mentioned anything about the trailer battery or where that 12 volts comes from. A good place the start is to check the voltage right on that battery as the stereo is connected and on. Then on its terminal connectors. Then if possible, measure the voltages closer to the stereo at any possible connector under the load. You're trying to find where the voltage has a large drop on the way towards the stereo.

-Don- Reno, NV

 

[Iron Duke II]

You have not mentioned anything about the trailer battery or where that 12 volts comes from. A good place the start is to check the voltage right on that battery as the stereo is connected and on. Then on its terminal connectors. Then if possible, measure the voltages closer to the stereo at any possible connector under the load. You're trying to find where the voltage has a large drop on the way towards the stereo.

-Don- Reno, NV

Thank for the input. I haven't been able to get back on this issue just yet. However, the voltage directly at the battery and the positive and negative wires behind the stereo are the same. Only when I connect the wiring from the stereo to the positive and negative wires behind stereo does the voltage drop to less than a volt.
The positive and negative wires for the stereo route into the exterior wall, though I do not yet know whether they go to the fuse panel or tie in directly to the main battery lead. I intend to pull the fuse/breaker/inverter panel to see if the stereo is connected behind it. There is a 3 amp fuse on the trailer fuse panel, however removing it has no effect on the stereo power connection at the stereo. Nor do any of the other fuses at the fuse panel.

 

[Mark_K5LXP]

The part I can't connect the dots on is that it's implied that the old stereo worked in that installation, just had some kind of speaker control problem. Putting the new one in revealed the power issue, then putting the old one back in the power issue remains. So following that sequence of events it sounds like during the course of the disconnections/connections something got crossed or maybe mis-identified and what you think is the 12V source is actually some other signal or control line. Just offering that when things go south like this you can't assume anything and to verify the sources and sinks to what they actually are.

Mark B.
Albuquerque, NM

 

[DonTom]

Thank for the input. I haven't been able to get back on this issue just yet. However, the voltage directly at the battery and the positive and negative wires behind the stereo are the same.

Then you have a battery problem. High internal resistance in the battery. How old is that battery? Does that battery work with anything else?

-Don- Reno, NV

 

[DonTom]

The part I can't connect the dots on is that it's implied that the old stereo worked in that installation,

But he also said "I went back and reconnected the old stereo to see if it was seeing 12 volt power with the same trailer connections and it reads 1.1 volts."

-Don- Reno, NV

 

[DonTom]

However, the voltage directly at the battery and the positive and negative wires behind the stereo are the same.

Need some clarification here.

With the stereo connected and on is the only time you should measure the voltage directly at the battery. Is that what you did? And measure on the battery terminals themselves, not the connectors.

If that voltage is low, you have a battery problem.

-Don- Reno, NV

 

[Gary RV_Wizard]

Seems to me if the stereo works on the bench but not in the trailer, the most likley suspect is a poor 12v- ground (chassis) where the stereo connects to the RV. A poor 12v+ source is a possibility, but that is easily ruled out by trying some other 12v device (lighting, etc) that uses the same source.

 

[Iron Duke II]

I switch the battery out and it fixed the issue. Thanks

 

[Gary RV_Wizard]

Luv it when the solution is simple!