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Pete
Pete, Mercedes Mechanic
Category: Mercedes
Satisfied Customers: 27148
Experience:  Over 15 years experience as a Mercedes dealer technician
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2002 ml320 radio on no sound, pulled fused f26 marked 70A

Customer Question

2002 ml320 radio on no sound, pulled fused f26 marked 70A terminal15?? waited 10 minute still no noise??
Submitted: 1 year ago.
Category: Mercedes
Expert:  Pete replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

This can be a common fault on this model here as well as other Mercedes models that I have seen and had to correct in the past before.Usually what causes this here almost every time is the sound amplifier itself with the sound amplifier needing replaced to correct this issue.I have had to replace the sound amp several times on several Mercedes models for the no sound issue when the radio and other audio components operate properly.Locate fuse F40 which is a 25 amp fuse and remove it for 5 minutes.Then reinstall this fuse to see if this resets the sound amp.If this does not work the amp needs replaced.If this does work and sound comes back you may be o.k. from here but it may act up again which indicates the sound amp needs replaced.If you need info on where this fuse is located let me know.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.
Our mechanic says it is the radio, I agree with you thinking it is amp, did not see f40 in fuse block by passenger feet, need to look in fuse block in engine compartment. do you lift and pull latches on fuse block cover? I do not want to break, is there a trick to open latches?
Thank You
Bill
Expert:  Pete replied 1 year ago.

The latches for the fuse box lid can be tough to open.Usually you need to lift slightly and pull back at the same time carefully to not break them as they can become brittle.I have had good luck using pliers to lift and pull back on these tabs to release the lid.

The radio is a possibility as well but the sound amp is more common for the no sound issue here.

Let me know if you need anything else and feel free to rate my help.

Thanks Pete

Customer: replied 1 year ago.
car is not here now will be back this afternoon will check f40Thank You
Bill
Expert:  Pete replied 1 year ago.

Your welcome

Customer: replied 1 year ago.
I have not had a chance to mess with car, I will tomorrow. When I try to reply to some of your messages it does not connect me to you??
Thank you
Bill
Expert:  Pete replied 1 year ago.

O.k.,let me know what you come up with here when your ready.Im not sure why it isnt connecting to me when you reply.It may be a glitch in the website that they may be working on.Make sure you come back to this post here when your ready.

Thanks Pete

Customer: replied 1 year ago.
How do I test fiber optics? How to remove amplifier?
If phone mod is back would that effect sound? CD changer?
Fiber optics to all said?Thank You
Bill
sorry taking so long I am busy with other stuff and wife is gone when I am home
Expert:  Pete replied 1 year ago.

I apologize for the delay as I was off line this weekend.

The fiber optics need tested usually with a dealers sds machine and in some cases a special adapter connected to the fiber optics especially when it comes to testing the fiber optic components to locate a faulty component.Below is the procedure on how to replace or remove the amplifier.

https://www.dropbox.com/s/hnogcgcaztziyue/amp-11-23.gif?dl=0

Remove/Install 1 Remove cover below instrument panel on left side NOTE: - Left-hand drive vehicle. - Right-hand drive vehicle. 2 Unscrew screw (1) and detach Sound amplifier (A2/13) from bracket NOTE: Lay insulation down to side. 3 Disconnect connector (2,3) NOTE: As of VIN A289565, X754620: only one connector. 4.1 Disconnect conductive coupling D2B NOTE: - Do not kink or stretch fiber optical cable. Press protective caps on conductive coupling and device connection. - As of VIN A289565, X754620. 5 Remove Sound amplifier (A2/13) NOTE: Do not damage leads and insulation. 6 Install in the reverse order.

If there is a phone add in installed the fiber optic loop does need reset and repositioned with its components learned in.This has to be done with a dealers sds machine.If this is not done this can cause a no sound issue and in some cases may cause other issues with the radio or cd changer.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.
still trying to get radio to work, I did find clear directions on how to remove amp, need to pull and get tested, is there an easy way to test or can a dealer test?Thank You
Bill
Expert:  Pete replied 1 year ago.

The dealer is usually the only or best place to have it tested but unfortunately they will need it installed in the vehicle for proper testing.They usually cannot test it with it out of the vehicle.The other option is to remove it and have an electronics repair facility in your area or maybe one you can send the amp to,test it to see if it needs replaced as they are usually the only ones that can test the amp and any other audio component when it is removed from the vehicle.

Thanks Pete

Customer: replied 1 year ago.
Do you know of a place to test amp? besides dealer?
If I can find used one for $100 or so would you try that?Bill
Customer: replied 1 year ago.
I have removed the amp and found one on e-bay for $41 in our area
looks the same, but one difference in PN ours is A163 820 27 89 his is A163 820 38 89
any ides if this will work or what the difference is?
would a dealer tell me?Thank You
Bill
Expert:  Pete replied 1 year ago.

I apologize for the delay.

A dealers parts department can usually tell you over the phone or if you stop in and talk to them if this part number interchanges with your vehicle.They will usually do this at no cost to you.I dont know of any facilities myself that can test this amp.You might check with local electronic repair facilities to see if they can test it for you.

Thanks Pete

Customer: replied 1 year ago.
Bought the $40 amplifier, still no sound, any thoughts?
Expert:  Pete replied 1 year ago.

That is odd as usually this is the sound amplifier at fault.Make sure the fuse hasnt blown for it.If the fuse is o.k. and since the amp was replaced the only other thing I can see is an actual fault with the radio itself unfortunately.Usually the radio will exhibit other issues when it is faulty but it is possible the sound chips/circuits in the radio may only have failed and the rest of the radio is o.k.The radio sounds like it needs repaired or replaced.

Thanks Pete

Customer: replied 1 year ago.
I did check the fuses, F40 under hood and the 20 amp fuse on the amp, both appear good. I do not know if amp is good, guy from e-bay said so, but who knows. He took his entire system out of his ML and is selling pieces, why was he replacing entire system?
Looks like I will have to go to dealer, or and electronic shop. Any other thoughts?
Bill
P.S. still cant see you current response unless I go to your old response??
Expert:  Pete replied 1 year ago.

I apologize if my responses arent showing up here for you.I see the responses myself here and it looks like you responded to my last post yesterday that I posted at 820 am.If you are still having issues let me know and I can send this to customer service to see if they see any issues.

The only reason I see why the seller from E bay would be selling off all audio components is if the vehicle is wrecked unrepairable or if he/she has replaced the entire system for another system he/she installed.

Unfortunately the only way to be sure the amp is any good is to see if you can find a repair facility in your area that can test it or to try and plug it into another like model to see if the sound then works.

Other then this if the amp is o.k. the radio does sound like it is the fault here and this may have to be tested further by a dealer or repair facility to be 100% sure of this.

I hope my info has helped here and if you need anything else let me know.Feel free to rate my help here.

Thanks Pete