Radio

[Timh1995]

Alright so I'm trying to replace the old broken factory radio with a car radio. The problem I'm having is the previous radio was for some reason tied in to a wire that's only 7 volts when the heater fan is off and only 12 volts when the heater is on... Ok so I tried pulling power from the external lights at the switch. Ok I have 12 volts now. When I plug in the radios harness I notice the 12v lights in the rv get brighter. I test the voltage and it's at 17v now and the radio isn't turning ok because it's rated up to around 15 volts. Does anyone have any idea of what's going on here because this doesn't make any sense to me how the voltage is going up without the introduction of an additional higher voltage source. On the radios harness I have yellow 12v red acc tied together so I don't need to use a switch to the the radio on (I also tested installing a switch on the red acc wire bit still voltage increase). I'm using the negative of my water pump and also tried using my rv door frame as a negative.

[valhalla360]

Timh1995 wrote:
My 12v power source is at a switch that controls the external lights, the always hot end of the switch is where I tied in to. it is an older converter. But it's not a random power spike. As soon as I plug in the radio the power increases from 12v to 17v and you can see the lights in the rv get brighter so it's not just a multimeter issue it's affecting the whole 12v system. I haven't checked out the battery yet. As far as I can tell I have a good ground. I get solid readings on my multimeter on the door frame of the rv or on the negative side of my water pump, both of which I used to try to get a ground for the radio and both caused a voltage spike.

Short of something really weird, the logical source of 17v would be the charger.

Hard to guess over the internet but if the voltage jumps, I'm wondering if the radio is drawing too much for some reason, so it triggers the charger to kick on but the charger is running at too high of a voltage and it get passed on as a 17v reading (or as possibly as suggested, it's not a clean DC output and the meter is giving faulty readings).

Try turning off the charger and see what happens. If the 17v reading goes away, its the charger that is causing the high voltage.

[larry_cad]

The black wire on the new radio is the same as the black (negative) wire on the old radio. Hook them together. The Yellow and Red wire on the new radio can both be connected to the red (positive) wire from the old radio harness. The green/white, orange, brown, blue, and pink are not necessary. The rest of the hookup is just speakers.

Both the original power wires should be suitable for powering the new radio.

The yellow wire on the new radio is to retain your new radio programming, such as which channels you want saved, etc. The red wire is for you to switch the power to the new radio off and on. Since you probably have an off/on switch on the radio, you really don't need another switch so just connect red and yellow together and hook them both to the positive wire from the old harness.

If you want to use the red wire to shut down power to the new radio, insert a switch into the wiring. This may save you some battery power when you aren't using the RV. You can also insert the same switch into the yellow wire which will remove all power to the new radio, which may also cause it to lose memory but will save battery power when not in use.

[larry_cad]

deleted

[larry_cad]

The black wire on the new radio is the same as the negative wire on the old radio. Hook them together. The Yellow and Red wire on the new radio can both be connected to the positive wire from the old radio harness. The green, orange, brown, blue, and pink are not necessary. The rest of the hookup is just speakers.

Both the original power wires should be suitable for powering the new radio.

The yellow wire on the new radio is to retain your new radio programming, such as which channels you want saved, etc. The red wire is for you to switch the power to the new radio off and on. Since you probably have an off/on switch on the radio, you really don't need another switch so just connect red and yellow together and hook them both to the positive wire from the old harness.

If you want to use the red wire to shut down power to the new radio, insert a switch into the wiring. This may save you some battery power when you aren't using the RV. You can also insert the same switch into the yellow wire which will remove all power to the new radio, which may also cause it to lose memory but will save battery power when not in use.

[Timh1995]

My 12v power source is at a switch that controls the external lights, the always hot end of the switch is where I tied in to. it is an older converter. But it's not a random power spike. As soon as I plug in the radio the power increases from 12v to 17v and you can see the lights in the rv get brighter so it's not just a multimeter issue it's affecting the whole 12v system. I haven't checked out the battery yet. As far as I can tell I have a good ground. I get solid readings on my multimeter on the door frame of the rv or on the negative side of my water pump, both of which I used to try to get a ground for the radio and both caused a voltage spike.

[DrewE]

What is your 12V power source? If it's an old(er) converter, it may be putting out very unclean, spikey power--basically rectified AC rather than smooth DC--and a multimeter could be responding to the peak voltage, rather than the average or RMS or whatever.

While it's hard to diagnose exactly what's going on over a forum--goodness knows it's sometimes very hard when you're there in person--strange, inexplicable changes in voltages are often the result of bad ground connections, sometimes in places that are not immediately obvious. Check them all carefully. I'd pay particular attention to the connections at the battery, and also verify that the battery cables themselves haven't corroded inside the insulation, which I've seen happen a couple of times. The terminal is tight on the battery, but the wire just past it is mostly (or entirely) powdered crud inside the insulation jacket.

[Timh1995]

the aftermarket radio harness

And here is the factory wiring harness
https://www.dlmanuals.com/manual/magnadyne-ls7600cd/owner-s-manual/9#pagetopwraplink