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Old 07-06-2020, 11:17 AM   #1
Junior Member
Join Date: Jun 2017
Posts: 14
Replacing entertainment head unit - different wiring harness


In my 2017 Roo, I am replacing an iRV31 head unit with a new iRV 31 head unit. The wiring harnesses on the new unit are different. For the power (A1-4 on the right), I am not sure how to proceed.

The old unit has:

A1 red (12V Pwr)
A2 black (GND)
A3 N/C
A4 N/C

The new unit has:
A2 Black (GND)
A3 Red (ACC)

With the new harness I ran A1 to where the previous was connected and A2 to GND. But nothing happens when turn battery power on. Since there was no A3/A4 on the old connector, where do I connect the new unit A3/A4 to? The same as A1? Images attached.
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tdischino is offline   Reply With Quote
Old 07-06-2020, 05:48 PM   #2
Senior Member
Join Date: Mar 2014
Posts: 2,332
The new unit has TWO 12V+ power connections, like most automotive units. A1 (yellow) is the direct connection to the battery for keep-alive when power in the car is off. A3 (red) is your primary 12V+ power connection, that would run to the accessory relay in a car. This allows the ignition switch to power the stereo on and off.

In most RV installations, these 2 wires are joined and tied to 12V+. This creates problems with the stereo powering itself on whenever there is a sudden change in DC line voltage (plugging into shore power, turning on the battery cut-off, and in my case plugging into the tow vehicle). I installed an on/off automotive switch to turn both power leads off whenever I was not using the stereo, eliminating speaker "pop" and parasitic draw. Drawback is loss of radio and equalizer presets (memory is dumped by turning all power off).

Fred W
2019 Flagstaff T21TBHW A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time
pgandw is offline   Reply With Quote
Old 07-06-2020, 06:59 PM   #3
Junior Member
Join Date: Jun 2017
Posts: 14
Fred W,

Thank you! I assumed it was pretty simple but didn't want to fry the unit for making an assumption.
tdischino is offline   Reply With Quote

entertainment, wiring

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