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Bypassing BOSE amplifier on SLK 320 and related problems

18K views 14 replies 7 participants last post by  jbanks15 
#1 ·
I am trying to find out if bypassing my BOSE amplifier that came originally with the car could have introduced 2 new problems. Immediately after I bypassed the amplifier my SRS light showed and the quiescent current consumption of the car is 860mA (the spec says it should be <=50mA) which destroyed my battery after 3 days of not driving the car. The original tape radio is Alpine CM1910 (208 820 11 86) and it controls the original BOSE amplifier AMP,3300,R170 RC,PROD (170 820 06 89) and the original CD-changer. I bypassed the amplifier by removing its connector completely and shorted the wires for the speakers so that a circuit is complete between each speaker and the new radio Pioneer 6800MP (MP3,WMA,Satelite Radio, etc). The new radio works fine. It's hard to believe that the amplifier removal is related to the SRS and quiescent current problem but maybe somebody has had similar experience? Is there a subwoofer that the amplifier was supposed to shutdown when the car is locked and now it's draining power? The bigger portion of the quiescent current is the trunk lamp not turning off after the car is locked (I lowered the quiescent consumption to 160mA after removing it). Does anybody know where the sensor for that trunk lamp is?
 
G
#2 ·
So basically then you are using the stock speakers with an aftermarket HU the BOSE is totally disconnected from the system right?

Not sure what you mean by shorted the wires for the speakers? I cant make much sense of that could you run it past me again please.

Depending on whats actually going on they could be related if you have not got the setup quite right but if the trunk light is staying on then the microswitch is probably bust and that could be keeping the car awake, the SRS is a little more complicated to figure out really need to know a fault code for that
 
#4 ·
More detailed information

Let me clarify what I did. I removed the amplifier physically and didn't put another one. By bypassing the wires I meant connecting the wires that come from the speakers to the amplifier and then from the amplifier to the old radio. Now the speaker wires run directly from the speakers to the new radio beacause I am not using the amplifier at all. The new radio has 4x50 Watts MOSFET and it works very good.

On the SRS light: I linked the car to Equus Innova 3120 OBD-II reader which can read most error codes and it says there are no error codes, no frame data, nothing, but the SRS light is still on.

On the quiescent current: I measured the quiescent current in more detail and here are the results:
Fuse #9 Roof light, hotn, anti-theft alarm, trun light 0.86A (0.16A when removed the trunk light bulb)
Fuse #18 E-call 0.28A
Fuse #35 Radio frequency remote control, hazard warning flasher, instrument cluster, tempmatic 0.06A

I read that the nominal value for quiescent current is <=0.05A(50mA) for the whole car and it has 0.5A even when the trunk light bulb is disconnected (1.2A when connected)
 
G
#5 ·
OK so with that setup i think we can say your audio system is not causing the problem and the info you have posted confirms that.

Like Bazzle said check your PSE all three of the fuses you have posted can be tied back to it because of the alarm.

With the SRS i am not even sure if the unit is hooked up to OBD in the 170 from memory because its a very pre-integration car so it might need a break out box to test them or a MB specific tester DAS(HHT)/CarSoft MB
 
#6 ·
I removed the PSE and checked the circuit for corrosion. There were no signs that water has ever been there. There was already a black plastic bag around the whole PSE, probably from the previous owner or the dealers, can't tell. What I noticed is that there is a black marker line less than an inch long on the bottom of the circuit, see attached picture. I'll remove that marker line and spray the circuit with protective coating. Since now the whole unit is disconnected I will measure the quiescent current again and see if there is any change. Is it ok to connect the battery when the PSE is removed from the car?
 

Attachments

#9 ·
The black marker line is only here to garantee that the manual check has been done : close to this marker line, there is two solder which can not be done autmatically. An manual process is needed. This marker line ensure that the manual control of this manual operation has been done.
Nothing linked to your problem.
 
#10 ·
Whatever happened with PSE problem?

Hi,

I read your post about changing your stereo and the battery drain problems that resulted.

I'm having the exact same problem you described, on fuse #9 , not the horn, not the dome, not the trunk so must be something about the alarm.

I'm about to check PSE, but I wonder if you can follow up on your post from 8 years ago :wink: and tell us how it turned out. You pulled out the circuit board and you were going to spray it with some kind of protector.

Thx in advance.
 
#11 ·
#12 ·
Thanks, actually, I sent a PM, but I also filled in an optional box (Trackbacking) that I am thinking put the post here too.

Anyway, this is indeed my problem too. As soon as I removed the power harness, my battery drain dropped down to a fairly steady 0.03 Amps. The PCB is corroded, especially at the connections, like an old AA battery was in there. It needs a good scrubbing. I'm going with a soft toothbrush, some water and baking soda for abrasion, and maybe an alcohol rinse at the end.

The only improvement I would make to bazzle's disassembly instructions for the PSE are on hist Step 6 and associated picture. I mistakenly assumed that you need the screwdriver to remove those clips. You don't. What really helps is light, especially down there in the dark recesses of the wheel well.

To remove the clips, press the top of the connector, and it will depress like a spring. Tilt the retaining clip forward (shown in bazzle's picture) and the locking mechanism will become self-evident, and you'll have no problem taking out the two connectors secured like that. The other two harnesses are pretty straightforward.
 
#13 ·
you think you sent a pm. you only have 12 posts and need 15 posts to send a pm. it did not go anywhere :D

If you wish to become PM (Private Message) capable, you need 15 posts. To get those 15 posts quickly, just go to the ‘New members introduce yourself here’ section and welcome enough new members to obtain your needed posts to PM.

set your options to keep a copy of 'sent' private messages
 
#15 ·
do this anyway for when u get to 15 so you will know if you sent a pm

usercp
edit your options
scroll down to private message section
check the box to 'keep' a copy in 'sent' folder

:D
 
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