AZ Roadrunner

I've finally located where the 300ma parasitic current drain is originating with the help of some of the posts here. When I pull out Relay 45 ("Bose Speakers") from the passenger-side fuse box, the drain disappears. I tested the relay on the bench (p/n 12193604) with my Fluke and the contacts are not stuck closed. The coil is reading 77 ohms. There is no short between the coil and the contacts.

A schematic I found shows that the power to the relay coil comes from the "Antenna Relay Coil Supply Voltage". Interestingly though, the power antenna does go up and down correctly when the Bose radio is turned on/off. So, I'm not making any sense of why Bose Relay 45 would stay energized with the contacts closed, supplying 'Hot At All Times" power to the Bose door speaker amps.

Additionally, I've tried to locate the "Bose Amplifier" which is called out in some threads as being above the passenger side footwell, but I'm not readily seeing it (without tearing apart the cabin molding). Is this the same thing as what is elsewhere called the "Bose Signal Processor"?

AZ Roadrunner

Lee DeRaud

I don't know without diving into the antenna schematics if there are limit switches or whatever to tell the radio when the antenna is full-up or full-down, but I suspect it thinks the antenna isn't where it should be and is continuously trying to move it there. I'd try disconnecting the antenna and see if the drain goes away.

CQRT

No up/down on 2004 Vette (in OP's profile) windshield attenna . . .

Lee DeRaud

Uh, he says it does:Profile says "convertible"...

CQRT

you're right Lee. . . I missed it - - sorry.

dadaroo

Not at home with all my info and FSM but can add more later.

The Bose Signal Processor in under the dash near the steering column. I don't think it moved between year models.

There is a amp in both doors for the Subwoofers only.

The radio provides all the amplification for the other 4 speakers. Two in the doors and 2 in the rear.

Your radio is powering Relay 45 when it should not. Need to look at my FSM to determine what may be the cause, your radio or something else.

Lee DeRaud

Agree. What isn't clear looking at the schematics is which piece (head unit or signal processor) is sourcing that signal, as it goes to (or comes from) both. I'd expect that the head unit sources it and it's used as a "wake-up" or enable signal at the SP, but the FSM never really says what happens where.


(Re my earlier conjecture: nothing feeds back from the antenna, so the radio/SP either just energizes the antenna motor for a sufficient length of time or does some kind of current sensing to determine when it's at one extreme or the other.)

Lee DeRaud

The Retained Accessory Power stuff is woven into the radio operation in arcane ways. Does the radio turn off after 15 minutes if the key is turned off and the doors remain closed? Might also want to pull codes and see if there are any data link (Uxxxx) codes active.

GCG

That's what I would expect too: the head unit, as the center of the system, controlling the rest of its components: turning ON or OFF the signal processor and subwoofer amps, while simultaneously making the power antenna go UP or DOWN.

Worth exploring these two possibilities.

dadaroo

Looked at the FSM.

If the radio is powering the coil in Relay 45 then the antenna should be in the UP position also.

Is this true? That radio output circuit is supposed to do both (antenna and Bose).

If the antenna is not UP when your drain is happening, I want you to put in a different relay and see what happens. You may have something in the relay contact side that is going on.

I know you tested Relay 45 but I still request you do this. I want to rule in or out an internal Fuse Box problem.

With the radio off, if the antenna is UP and the drain is occurring then there should be some internal radio problem.