Ooh... stealth... sweet.

After looking at the Prius stereo system with an Oscope I can tell you that it is different. From what I can see the head unit outputs left and right channels as differential 1v signals. These signals are not effected by volume or balance. This makes connecting the rio much easier! There is a second connector on the head unit that comes from the steering wheel. It has five wires and they are vol up / down, selection up / down and mode. There is a serial data line on the main connector. This carries the signal that controls volume. Volume, balance, fade, must be handled by the remote amp. When I am done the existing controls should be able to work with the Rio just like they do with the existing stereo. All I should have to do is install a 4PDT 12volt relay that is energized by the amp out of the Rio. This will switch the audio outputs of the head unit out and the outputs of the Rio in. I will also use the amp out to fire up the remote amp if needed. Not sure yet. More to follow. All in all connection looks like a breeze.

Oh yeah one last thing. I thought I would put the car back together without the stereo so I could drive it. When I started the car the touch screen was pretty much useless. No climate control, no nav system, nothing. It told me that it had lost connection with these devices. Reconnecting the head unit brought everything back to life. It looks like the data stream that controls all this stuff goes through the stereo. FYI

I think that's the most buttons I've ever seen on a steering wheel!

-brendan

All I should have to do is install a 4PDT 12volt relay that is energized by the amp out of the Rio. This will switch the audio outputs of the head unit out and the outputs of the Rio in.

This sounds like the now-discontinued Sony XA-39-II audio switch.

Good luck finding one...

tanstaafl.

The P.I.E. MPSS-4 was just linked by Tony Fabris in another thread...
Functionally pretty much the same thing as the old Sony unit.

/Michael

That looks like it might work but it does not say if the ground side of the line input is switched or not. This would be bad in my case as the existing head unit is differential and the rio is single sided. For this reason I will use a 4PDT relay that will switch all of the line level leads. Bought one today for 15 bucks.

The rio is now snug in it's sled. In the Prius. Here are a couple of pics of what I did with the sled and the harness I made. The RCA jacks could have been removed as they are for the rear channels and not needed. The sled is riveted in place. You can see the relay rtv'd to the back of the sled. This switches between the normal head unit and the rio. All of the in car controls work with the Rio! I have bass, midrange, and treble along with balance fade and volume. This really is a pretty cool car. I will post some pics of the finished install after I get the inside of the Prius cleaned out. It is still full of all the tools used to do this. I will also list there the order of panels to be removed for anyone else out there wanting to brave this.

Wow. Beautiful install. The workmanship looks superb. Be sure to post a couple pics of the completed project when you get everything put back together

Here are three pics of the finished install.
/
/
This one is of the console all closed up with everything off. The Rio is hidden.


This one is still closed but with the Rio on.


The last is of the rio with the door open.

In order to remove the existing stereo the dash panels must be removed. They are all interlocking and must come off in a specific order. This is for an option 8 USA Prius. Use this guide at you own risk. I don't guarantee the accuracy of these instructions, sorry.


1. Remove the bottom center section. There is one plastic "screw" on the passenger side. This panel will now pop out.

2. Remove the vent assemblies from the right side of the center console and from the far left drivers side( on left side of steering wheel next to drivers door). These panel just snap off. It is the entire silver panel.

3. Bottom dash under steering wheel. There are two screws in the bottom of this that need to be removed. Then just snap it off. It's attached with wires and the hood release so it will just hang there.

4. Upper dash above steering wheel. This one just snaps off. It also is attached by the start button.

5. Vent left of center console. This one just snaps out. You can disconnect the park button so it can be removed.

6. Remove the two 10mm screws holding the touchscreen in and pull it out. It comes out by pulling it directly back. Disconnect the four cables going to it and put it in a safe place.

7. Center console piece below stereo. This just snaps out.

8. Remove the two lower and two upper 10mm bolts that hold the existing stereo in and yank it out. Disconnect the 3 cables going to it.

Thats it!

Neutrino,

That really looks nice! You did a terrific job at making that look stock. Gotta love that translucent door, too.

Did you happen to make any notes on your electrical connections? I'm seriously considering ordering a Prius, and I'd be looking to follow in your footsteps pretty closely. I have the same relay setup (using the Sony switch) and find it is very handy, indeed.

Do the steering wheel controls directly affect the amp, then? I'm guessing that, since you say they work for the empeg, as well as the factory head. I'm also guessing you have no controls in the wheel for next track, etc.

Thanks very much for your detailed documentation -- should make things much easier for me down the road.

--Dan.

Thank you, and your welcome

The color codes are :

POWER

• memory........blue
• ignition..........grey
• ground..........brown
• illumination...green
• dimmer.........white / black
  

SPEAKERS

• Right +...........red
• Right -............green
• Left +..............white
• Left -...............black
  

I used the illumination wire to dim the Rio. It is a full 12v and cycles with the headlight switch. The dimmer wire is variable with the dome light thumb switch.

I am not sure that I have the polarity of the speakers correct. These signals are differential on the Prius. I based + and - on Oscope readings and color data from a generic Toyota wiring list.
If anyone has a Toyota wiring list for the 2004 Prius it would be great to know if these colors are correct or not. It does seem to sound correct.
You are correct in your assumptions that the volume control on the steering wheel is the only control that effects the Rio. The mode and up / down buttons still work with the existing stereo only. This buttons do provide discrete inputs to the head unit. It would be quite possible for someone to add another relay and port one or all of these switches over to the rio. Using a couple unused contacts on the Rio connector and modifying the Rio. It would be possible to make them work. If there was one function I would like to have it would be pause. I may look into this after I have enjoyed my new car and the Rio for a while. It was undrivable for a week while I made the Rio upgrade.

CYA
C

Thats a nice install, if only the dash on my clio came apart that easily.

Not strictly on topic for this thread, but I hear someone has figured out how to add the stealth mode button to U.S. 2004 Priuses. (Supposedly to make it easier to get approval for use in the U.S., they left it out, whereas in other markets it's there)

No details yet on how.

Not strictly on topic for this thread, but I hear someone has figured out how to add the stealth mode button to U.S. 2004 Priuses. (Supposedly to make it easier to get approval for use in the U.S., they left it out, whereas in other markets it's there)

That would make it run off electric all the time then ?

Well, until the battery discharges. Then, the ICE fires up again.

That would be cool. I can tell you from experience that it won't last long. About a month ago I awoke to about a foot of snow. I had put studded snow tires on Grendal (the Prius) two days before. After trying to get out of my driveway for about 5 minutes I broke down and made a path with the 4X4. When I got back in Grendal I noticed that the battery was discharged enough to light up the warning lamp in the dash. I think I had one bar left. This was under very heavy load but it sure didn't last long.

Yeah, I figured. It's not that big of a pack.

Dragging up an old thread here, but I'm considering a Prius for my 600 miles/week commuting (now that I know it's empeg-capable). I drive a good 80mph pretty consistently (save for snow, cops or heavy rain) as it's all open, rural highway. Is the Prius capable of handling comfortably at 80? How does cabin noise compare to other cars?

-Zeke

I guess the speed limit anywhere near the Bay Area isn't going to be high enough for me to try. I'll have a 2004 Prius as a rental next week.

What's speed limit got to do with how fast you can go?

-Zeke

Zeke,
You should also consider one of VW's TDIs (diesel). I drive a Golf for my daily commute of 80 miles round trip and get over 700 miles per ~$28 tank with a heavy foot.
I'm in northern MA about 30 minutes south of Nashua if you'd like to meet up and for a test drive.
There is also a decent forum over at Fred's that supports the VW TDI nuts, and it's got a good ratio of knowledgeable people.

Thanks for the offer & the info. I'm not really that serious yet, but I know the day is coming for my 188k '99 Forester, so I'm scoping out the options. Despite my wants for a $40k SUV, a $20k econo-car is the right thing to do since I basically make a new car almost worthless in 5-6 years (I avarage 36,000 miles/year).

-Zeke

Accelerating to 80 was no worse then in my Saturn SL2. The cabin noise, thats another question, I can't really remember it all that well from the test drive. I'd guess though that again it was no worse then the Saturn I drive, since it doesn't stand out in my mind as a negative.

The only negative I had with the Prius was the dealership. Completly ignored at one, then the second, had a sales guy get all pissy with me including discussing economics when enquiring about the employee discount agreement between HP and Toyota. He also tried to steal the sale from the first sales guy I talked to, and was happy to deal with.

In the end, I decided I didn't need another car, and paying off my Saturn right now should be a priority, since the loan amount left is higher then bluebook by a bit.

I guess I should take it up into the hills; It lacks the quick burst of power of the cars I'm used to when you punch it, but it feel almost exactly like my friend's Saturn Vue, which I assume means it's a circumstance of the CVT.

Those image links have all died. Are the pictures still available?

I wanted to print some to take to Cambridge Car Audio this week so I can ask them to make something similar...

I looked at a couple of toyota dealers and was ignored also. Aren't toyota sales people on commission ?

Most Toyota Dealers are complete muppets.

My wife ended up shouting at one, which was nice becuase normally she shouts at me !!

Well, the new Prius arrived yesterday. Maybe this weekend I'll rip the dash apart for the first time and start scoping this out. Charles' photos have disappeared, unfortunately, so I'll have to replicate some of his work. He did document the wiring codes, which should be a big help.

--Dan.

I am also interested in insatalling an EMPEG unit (when I get one) in my Prius. I also have a SIRIUS PNP unit in my car. When Costal Dave gets his AUX-IN kit finished will I be able to connect the EMPEG unit to the RCA inputs on his kit and the SIRIUS unit through the EMPEG?

Peter
Miami, FL USA