Hi,

I have a 2004 Subaru STi and have had the AVIC-D2 installed for awhile. However, the radio signal is very, very weak. I listen primarily to CDs, so it hasn't been an issue, but I'd like to address it. Does anyone have any ideas which wires I should check/verify connectivity with?

Thanks

Start with your antenna

Make sure the power antenna wire from the D2 is connected to the vehicle's power antenna (or) antenna booster wire.

Make sure the power antenna wire from the D2 is connected to the vehicle's power antenna (or) antenna booster wire.

Thanks, I'll check that. I do recall the wire that plugs into the back of the unit being connected (it has its own hole on the back of the D2). Is this a separate wire that you're referring to?

No, not the actual antenna wire, that wire carries the radio signal to the unit from the antenna (but you would want to check that anyway to see if it's snug), but there's a blue wire coming out of the radio's harness (the harness with the power and speaker wires) that is used to power up/turn on a vehicle's power antenna and/or antenna booster. Chances are if the antenna is plugged into the back of the unit, but the reception is still terrible, the car is equipped with an antenna signal booster that isn't powering up.

The wire you're referring to is the actual antenna wire. The wire that hifisi is talking about is the blue wire in the wire harness you bought for your car. If it's connected to the blue wire of the avic, try hooking it up to the red wire. It's been my experience that some aftermarket radio's power antenna lead doesn't provide enough current to turn on the antenna amplifier in subarus.

Thanks for the help. I have it apart right now. However, there is no blue wire in the harness in my car. When I installed this, I had a pre-existing harness from my old head unit that I used for the AVIC-D2. However, there is no solid blue wire coming out of it. Interestingly, in my old head unit, the radio reception was fine, so it must be one of the wires. Right now, I have every wire from my car's harness connected to the corresponding colored wire on the AVIC-D2's harness and the only leftover is the blue antenna wire. Worth noting, everything is fully functional except for the powered antenna. Any ideas?

Thanks again.

Yeah. Hook the blue wire to the powered antenna.

Here's a summary of what I'm seeing:

Male connector from the car harness has a blue wire-->Plugs to female end of AVIC harness (in which the pins of the blue wire on the car's end correspond to a yellow wire on the AVIC's end)-->Other end plugs into back of AVIC. Why is the blue wire, which I'm assuming is the power attenna, plugging into a yellow wire? This was how it was pre-wired from the factory, so you don't think it was my mistake.

Thanks!

If your car has an amplified antenna, it needs power to pick up radio signals. Your just looking for a wire that is coming from the D2 to power your antenna.

The colored wires for the speakers have to be correctly match so that sound coming from your HU goes to the correct speakers. Doesn't matter so much when your just looking for a wire to power your antenna.

Well, I think the cause was the harness from the old head unit. There were two inputs with no wires coming out, but there were wires there on the car's end. I just ordered a SCOSCHE SU03B, so that should do the trick. Sorry for the trouble and thanks a lot for the help!!

I got the new harness and soldered everything together. However, no improvement in radio reception. The new harness has the blue wire for the power antenna and I connected this to the AVIC's harness, but it's no better. Are you sure that hooking it to the red wire is okay? Is the power antenna wire's sole purpose to provide power. If so, why wouldn't they have you just wire it to the red one to begin with?

Thanks.

The wire you're referring to is the actual antenna wire. The wire that hifisi is talking about is the blue wire in the wire harness you bought for your car. If it's connected to the blue wire of the avic, try hooking it up to the red wire. It's been my experience that some aftermarket radio's power antenna lead doesn't provide enough current to turn on the antenna amplifier in subarus.

It wont cause any problems. I have done that on more cars than I care to count. If it concerns you that much get a relay and wire it up like this.

pin 85 - Power antenna lead from avic.

pin 86 - Ground

pin 87 - +12v

pin 30 - power antenna lead in scooby doo harness.

Sounds good, thanks! Is that the power antenna wire's only purpose though - to provide power?

So, just to clarify, without the relay, I would go from the red wire in the Subaru's harness to the blue wire in the AVIC's harness?

It wont cause any problems. I have done that on more cars than I care to count. If it concerns you that much get a relay and wire it up like this.

 

pin 85 - Power antenna lead from avic.

pin 86 - Ground

pin 87 - +12v

pin 30 - power antenna lead in scooby doo harness.

No, it would bypass the AVIC all together. Red ACC wire from car to the car's power antenna lead, which basically switches on the power antenna whenever you turn the key on.

Sorry for all the questions, but if it will bypass the AVIC, how will the reception improve. Also, why is there a lead on the AVIC's harness for it if it could be connected to the red wire in the first place?

Thanks

No, it would bypass the AVIC all together. Red ACC wire from car to the car's power antenna lead, which basically switches on the power antenna whenever you turn the key on.

The antenna signal doesn't bypass the AVIC. The power going to the antenna booster bypasses the AVIC. It's basically using the car's key as the power switch for the booster instead of the AVIC. The reason radios have power antenna outputs is because if they are used, the antenna booster (or retractable antenna, if that's the case) would operate when the radio is powered on or off, not when the car is. Because you don;t need to power the antenna booster if you're driving with the radio off, but it doesn't hurt.

So, I ended up getting the radio working (finally). It just would not work when the blue wires were connected together, so I connected it to the blue/white wire that my subwoofer amp is connected to. That way, at least if I have the AVIC off, the radio amp won't be getting power; versus the red wire, which would have provided constant power whether the unit was on or off (until the ignition was shut off). Does anyone have any ideas why the blue wire to blue wire connection didn't work? I tested it with a voltmeter and verified that my "solder job" was good.

Thanks.

FYI, the AVIC is on as long as the car is turned on. You can't power it off without turning off the car's ignition. So in this case, it's the same thing.

Like I said about 20 posts ago, the antenna output of aftermarket radios provides a limited amount of current. In some cars this is not enough to power up the antenna amplifier. Oh and as HifiSi said the blue/white wire in the case of the avic acts EXACTLY the same as the red wire.

I think the am/ fm antenna on my z1 is weak to say the least and I don't have a power ant on my Tundra. Is there any way's to improve the signal strength?

Buy an antenna booster. Not a very expensive item.

http://www.digital-comfort.com/store/proddetail.php?prod=AB150DSF

Don't know how good they work, but it's cheap enough that it's worth trying.