G'day forum team,
I posted this
'Tweak' that I've implemented into my own stock (entune) audio system with another Toyota t/s 'message board' and felt that I should post it here as well; hope it will be useful! Even if you're not utilizing a
1.5KW subwoofer system in your truck, it's still one of the best
free audio system mods I've ever done! Over the last couple years, I've heard more than a few people say something to the this effect... "My 4runner's stereo system sounds way better with the '
party mode' button on, but I wish that the backdoor passenger area speakers could be left
on when I'm using it". Now, I had been feeling the very same way when listening to music in the truck for quite some time, so I decided to look into Toyota's audio system design to better understand exactly what this system does, and how it works. There's one other thing I think I should mention. If you're using an "independent" subwoofer system in your truck, then I know you may be experiencing some of these very same issues e.g., Trouble balancing the rear channel w/ the front speakers because the rear channel just isn't loud enough. Or, problems
integrating the low-mids and upper-bass freq with the subs. If those are some of the issues that your
stock 4Runner stereo system suffers from and you really don't want to replace the o.e.m system w/aftermarket equipment, then here's a way you can take more control of it.
Before I get started I'd just like to say that when I began making these changes to my vehical, I never had any intentions to..."write it up" as such; really just hoping to get it over with. For this reason I didn't take any photos during the early stages of this task; for that I offer my most sincere apologies. First, I looked at how the party mode circuit actually works. The function of this circuit is two fold. It's first appointment is for the party mode "switch" to control two rear channel "speaker selection" relays, located on the passenger side behind the glovebox. These two relays manipulate the left and right, rear audio channel's speaker wiring in such a way, that when party mode is
NOT activated,
all four L/R side
4ohm speakers are operating together in a
series wiring configuration
[pos]---
O---
O---
[neg] totaling 8ohms.
When the pm circuit is activated, the switch completes a ground (gnd) circuit to the speaker relay coils. When these relay coils are provided a ground circuit, the speakers'
series wiring is reconfigured to disconnect the two backdoor speakers all together, and then employs the (4ohm) rear tailgate speakers instead. By employing only the 4ohm tailgate speakers (as opposed to the 8ohm
series wiring when party mode off), the amplifiers will now be capable of generating their
full rated output into the left & right channel's 4ohm speakers. So now the acoustic output from the system will be increased by a factor of ^X2 (double). The party mode circuit's second appointment is for the pm
switch to control an "EQ filter circuit", which is built-in to the head unit.
When this EQ filter circuit is
OFF, the stereo system can sound 'bland', with muted highs and mids that lack definition. Also, a "far away" sounding, low/mid frequency reverberation is introduced as a result of "off-axis", poor tailgate speaker positioning/distance; w/regard to the driver seat location. When the EQ filter circuit is
ON, however, the audio system takes on a whole different character. The 'mids' become much more articulate, and the highs are brilliantly striking, w/presence and very high resolution. This is the
only reason that I ever used party mode. But I decided to change things around so I could benefit from the high quality audio sound w/o losing the two backdoor passenger area speakers.
The way that I've configured my 4Runner's rear channel speakers (front speakers are unchanged) is, I've disabled the two relays that the party mode button controls by
not allowing them a ground source which is provided by the pm switch.
Note: *These relays are energized by the 7.5A fused acc (accessory) circuit when the key/start button is initiated. **this work is completely reversible.
PS: The 'Mitchell' wiring diagrams that I'm using here are the "printable version" however, they cannot be shared (transferred electronically), which is why I chose to photograph them.
The diagram above shows a 5'th gen 4Runner radio circuit w/built-in amplifier and navigation; JBL is
not included here. To keep it simple, the party mode switch is shown in the upper left hand corner, and the head unit is just below it. The
pink traces represent the
ground circuit wires that run in between the components,
yellow traces show the
power circuit scheme.
This is a full radio wiring diagram as mentioned above. If you look to the extreme upper right at the other end of the pink traces, you will see the L & R "speaker selection" relays. But for this party mode reconfig, we won't be needing to do anything w/ those relays directly. Everything that needs to be done, can be done right from behind the hu and pm switch. For this mod to be done, you only need to move one wire and by doing that you will disable the relays "that disable your 'second row' backdoor speakers", and maintain the
'higher quality' EQ audio filter circuit at the same time, see below:
The easiest way to do this is just to remove the head unit and the party mode button trim panel from the dash. The idea is to allow the party mode button to continue to activate the 'EQ audio filter circuit' (built-in to the head unit) as it always has, but without permitting it to disable the backdoor speakers. There are four wires in the pm button harness connector; 2 for the party mode circuit, and 2 for the instrument panel illumination circuit. They are: white, white w/black stripe, gray, and green. In the diagram above, see the plain
white wire (not the one w/black stripe), at the
woofer speaker switch (party mode switch), terminal#6 w/pink trace leading to the yellow dotted line. That's the one that turns on party mode. Now follow that yellow (dotted) trace to the other
white wire at the hu, terminal #1. This is the EQ audio filter circuit term; this is the
only terminal that we want the pm switch to activate. Here (below) is an actual photo of the harness conn on the back of the head unit:
"CONTINUED BELOW!"