Great info!
 

This is great new info! Now we're getting somewhere. This sounds like this just might be "the common Bose/Millenia problem." I'll check my trunk relay today.

Brain storming:
I think you are right, the power source for the relay is probably the radio. It may be some sort of pre-amp signal or initial power boost to the amp via the relay. (Having a relay prior to the amp seems a little weird to me, but then I'm no engineer. :))

If it is the radio itself, this would add credibility to the tech rep's statement that "it is usually the head unit on the radio." (Whatever a "head unit" is. :))

More troubleshooting info: I bought what I thought was a good $35 used radio to replace mine. It didn't work any better..... same exact symptoms.... lit up, etc., but no sound. The connections on this radio were slightly different from mine and the rear of the radio had a distinct add-on compartment along the back of the case. (My radio case is just one piece.) Everything alse is exactly the same.

I took this compartment apart to see what was inside. It has an electronic board inside, but the surprising thing was that it had a typical 10 amp auto fuse on the board. It was a fuse just like the ones in the car..... a red 10 amp. Also surprising: the fuse was NOT blown. I reseated it, but no help. (Is this the "head unit?")

FYI: I did not take my orig radio apart because it looked a bit more complicated and I was afraid I would damage it. From the inspection I did without opening it, I didn't think my radio had the fuse. I don't recall why I thought that. But from what you have found regarding the lack of power to the relay, I am thinking it might be worth opening the case on my orig radio & inspect for this fuse.

If there is no fuse, then the diodes, capacitors, etc. that produce the "output power" on the board are probably blown..... I suspect. I think this is more likely since with a blown fuse the "no sound" problem would not be "on again, off again, on again" as it was initially. But it could be with a diode, capacitor, or etc. slowly going bad.

Sorry to be so gabby, but 2 heads are maybe better than one? :)
Stay in touch, and good luck.

If anyone else has any ideas, please chime in.

Possible solutions...
 

I am thinking about 2 possible solutions to fix this with messing around the head unit.

1) Disconnect the two wires that connected at the relay at the relay and connect them with a manual switch to simplely act as a manual relay. Just turn on the radio and then turn on the switch, but I have to remember to turn off the switch when I turn off the radio. Otherwise the AMP will be alway on (this will reduce the AMP's life).

2) Find a switched 12v source from some other accessory and connect it to the relay. I am thinking about the ant. source since my ant. still working. I think you said your ant. is also working, so this could be the best 12v source.

Do you find anything wrong with my apporches?

Good ideas
 

I like the idea of using the ant voltage to operate the relay. The ant wiring should be nearby & easy to splice into, plus the ant gets power as soon as the radio is turned on. However, I don't believe it gets power when the 6-CD player is on. That could be a problem.

Questions for you:
Let me make sure I understand what you said previously: when you manually close the relay you said you got "sound." Is this radio/cd sound.... ie...music? Or is it a hum or an "open speaker" sound? If music, does it sound normal? Also, is the sound only coming from one speaker?

Since each speaker has its own amp, I assume each has its own relay? This would make splicing to each relay necessary, and too hard in my opinion. But if the one relay works all speakers then splicing an alternate power source to it should work. Maybe with a little trial and error you could get the ant power to operate the relay when the CD is on?

If each speaker has its own amp then you would need to splice the new power source to the main relay wire at the radio (ie...before it branches out to each relay). I guess you could use the main power source coming to the radio but then you'd need an on-off switch as you mentioned before. That's a little cumbersome and potentially unsightly, depending on where the switch is located. But workable.

Either way is a bit complicated, but from what you have found about the relay voltage being absent, splicing in another souce should work. As you already know, the trick is to get the anternate souce to go on-off with the radio & CD.

Let me hear back soon. Thanks.

Can't find the right 12v source yet.
 

Yes. when you manually close the relay I got music (radio and CD) all speakers worked.

Thank you for your reminder that the ant power is only for the radio. You're right, the CD is not going to work if I do that.

So, now I have to keep searching for a 12v source when the head unit is on. I will try to test the CD connector or the speaker connector to see if I could find it over there.

If not, I'm think just connect a switched 12v from the fuse box to the relay. This way, when the car is running, then the AMP is on even the radio is off. Most of the time, I will turn on the radio or CD anyway.

The last resort will be the manual switch.

Would this work?
 

How about this: since the sound works when you manually close the relay, could you put a small wooden shim or spacer in the relay box which would force it closed all the time? The amp might be on all the time, but that's same with the other options, except the switch option. I guess there's a possibility the amp wouldn't be on when the radio is off???? Trial & error would tell.

I hope to be getting my amp back from Florida soon so I can try it.

You've discovered a bunch of good info in all your troubleshooting that will be helpful to the many others who have or will have this same problem. Good job. :)

Stay in touch. (My computer was inop the past few days.)

Eureka!
 

I got my amp back today, reinstalled it, and opened the radio relay (H300). I then inserted a toothpick across the contact housing, forcing the contacts closed. I then broke the toothpick off, replaced the relay cover, and reinstalled the relay. Everything works great!!!..... AM, FM, 6-CD player, Antenna. Yahoo! https://www.mazdaforum.com/forum/ima...ons/icon14.gif

I had forgotten how good it is to have a radio! :)

:confused: I have no idea why closing that relay makes it work, but am glad it does!

There MIGHT BE problems doing it this way:
1) The amp may be "ON" constantly and burnout prematurely. (No big deal since it wasn't working anyway.)
2) There may be current flowing constantly through the components to GROUND even with the ignition turned off. This would probably drain the battery. Not good.
3) I really doubt forcing the relay closed would cause a fire hazard, but be aware of the possibility. This Bose system is strange! So beware! :eek:

I will follow up if I have any such problems.

BTW, I did troubleshoot the radio relay to see if it was defective and therefore the culprit. It wasn't. I switched it with one of the other known good H300 relays that are right next to it and it still didn't work properly. It must be the lack of 12V current as found previously).

(For others: There are three H300 relays side-by-side in this area. They are attached to the right side of the rear seat back, behind the carpet in the trunk. The radio relay is the middle one. I believe the good one I used operates the trunk lid or possibily the door locks because it caused a loud kerthunk noise when operated. Don't know what the 3rd one does.)

Good luck, and thanks for sharing the info you found regarding the relay!

Update
 

Update to the work-around of permanently forcing the radio amp relay closed: No new problems..... no fire, no drained battery. Everything works and sounds great. https://www.mazdaforum.com/forum/ima...ons/icon14.gif

However, there is one slight annoyance:
Each time you turn on the ignition: there is a semi-loud pop from the speakers for a split-second. It is obviously being caused by the sudden spike of electrical current to the amp. It'll make you jump if you're not prepared for it. It happens whether the radio is on or off, and no matter what the volume level is set at. It's just a minor inconvenience to me, especially when compared to not having a radio or having to spend mucho bucks to replace or repair it all.

It is so great having a sound system again! :)

Update#2
 

Sorry to have to report that my previous method/fix (force the radio relay closed with wooden toothpick) DOES drain the battery. :mad: So, it's back to the drawing board on finding an alternate source of electricity to turn the radio on/off.

As previously discussed:
(1) One method would be to wire an inline on/off switch to the radio power input wire at the back of the radio. Obviously, this switch would need to easily accessible near the dash to turn the power to the radio on/off. This might be the best solution.

(2) Another way MIGHT BE to be bypass the radio relay and splice its wires into the wire used to power (raise/lower) the antenna. This might work since the antenna is only powered when the radio is turned on & off. However, I suspect the antenna's relay may turn off the power once the antenna is fully raised or fully retracted. If true, this would turn the radio off after the antenna has done its thing, and therefore wouldn't solve the problem. HAS ANYONE TRIED THIS?:confused:

Any other ideas?

Good luck.

Hey!
 

The Millenia hosts a modular radio. (Bose)

You can tune your radio to a station, Pull the head unit out and,.. You guessed it! Still making sound!

All years:
Constant 12v+ Wire: Red/Black
Switched 12v+ Wire: Blue
Ground: Black
Illumination: Green/White
Dimmer: N/A
Ant: N/A
Amp: N/A
LF (+): Yellow
LF (-): Blue
RF (+): Pink
RF (-): Purple
LR (+): Green
LR (-): Yellow/Green
RR (+): Green/Black
RR (-): Green/Orange

And Alarm for 2001-2002 *** For the heck of it.

12v+ Positive Wire (+): Green
Location: Ignition Switch Harness

Starter (+): Black/Yellow
Location: Ignition Switch Harness

Ignition (+): White/Green
Location: Ignition Switch Harness

2nd Ignition (+): Black/Red
Location: Ignition Switch Harness

Accessory (+): Blue
Location: Ignition Switch Harness

Key Sense (-): Blue/Black
Location: Ignition Switch Harness

Parking Light (-): Light Green Or Red/Yellow
PLocation: At Steering Column Harness

Parking Light (+): Orange
Location: In Drivers Kick Panel, Harness To Rear Of Vehicle

Power Door Lock (-): Blue/Orange (1-Wire Door Lock System).
Negative through a 1,000 ohm resistor will lock the doors and arm the factory security.
Negative on the same wire will unlock all doors and disarm the factory security.
Test using the passenger door key cylinder switch with all doors closed. To disarm without unlocking,
send a (+) positive voltage to the blue/yellow(+) key sense wire. Some units will also require 2 extra relays.
Location: In Passenger Door Harness

Power Door Unlock (-): Same Wire As Above
Location: N/A

Door Trigger (-): Light Green
Location: In Drivers Kick Panel, Harness To Rear Of Vehicle.

Domelight Supervision: Use Door Trigger, Requires Relay
Location: N/A

Trunk Release (-): Purple/White (Requires Relay)
Location: In Drivers Kick Panel, In Harness To Rear Of Vehicle

Horn Negative (-): Green/Red
Location: At Steering Column Harness

Tachometer (-): Orange
Location: At Diagnostic Connector. The diagnostic connector is in driver side rear corner of the engine compartment.

Brake Light (+): Green/Black
Location: At Switch Above Brake Pedal

Factory Alarm Disarm (-): Light Green/Red
Location: In Drivers Door Harness

Factory Anti-Theft System: Transponder Anti-Theft System, Requires Bypass Module and Extra Ignition Key
Location: Transponder At Ignition Switch Tumbler

Here is an image of the connectors for the CQ-YM3310A (CD Changer I believe) and the CQ-LM3312A Radios.

http://www.carstereohelp.net/images/...ia03180201.jpg

Now theoretically, the amp is powered but not all the time.
So find the power wire for the amp and jump it to the trigger on your relay.
When the car turns on the amp turns on.

Because the Bose radio system is modular they can create the most astounding sound quality in a pretty simple setup (If you know what you are looking at.) The head unit (Houses th CD player, display and buttons only.) controls the radio/preamp (On the back seat.) Which controls the 2nd amps/speakers. Simple right?

@ Gabby1234
 

The power antenna has 3 wires.

Constant (When the car is on.)
Ground
ACC - (When the radio *AM/FM* comes on)

Now when power is supplied to the ACC wire the Antenna comes up. When disconnected. NOTE: Disconnected** the antenna comes down. Meaning that the ACC wire is constantly powered during antenna operation.

But the source power for lowering the antenna is switched by the ignition. Another source for the preamp.