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- Sent: Monday, January 14, 2002 10:15 AM
Subject: SRS Light on 1994 E320
> Hi Jon, love your site and thanks in advance for such a wonderful
service.
>
> My 1994 E320 SRS is constantly on. I purchased the car about a
month ago
and need to buy a repair manual for it.
>
> Could you give me a few areas to check where my problem might be?
Any
recommendations on a repair manual?
>
> Thanks,
> John
- Sorry it took me this long to get back to you. I did get your other emails
and actually started an email to you a few days ago but it got to be too
late. The SRS system on your car is not something that should be messed with
until you have some documentation. I would go to www.germanstar.net
and get
the repair manuals on CD for your car. Ron will be happy to help you. Tell
him benzdoc told you. The fact that the light is on all the time is a very
bad sign. There are two scenarios. First is that the car was in a accident
and at least one of the seatbelts activated or maybe even the air bag. The
SRS seat belts can work independently of the airbag also, then the car was
repaired half way and sold. Second and most likely scenario is that your
steering wheel contacts are faulty and caused a short circuit in the main
SRS control unit. Big Bucks. The control unit can take only so many false
hits before it quits. Ron can also help you with one of these at a
substantial savings over the price at the dealer. You will need an impulse
counter to check your system. The SRS control unit if it is still functional
will give the tool pulses, it counts the pulses for you. You them consult
the book of knowledge and it will tell you what the corresponding # means.
Your 94 has a connection block by the battery, mounted on the inside of the
first firewall. I am sure you have seen it. You can purchase the impulse
counter from www.asttool.com . You
might also check on ebay for a use one.
They are expensive. I am going to assume that you will need new contact
rings and brushes on the steering wheel and a new control unit, this is most
common. The control unit in mounted below the radio in the center console.
It is mounted to the frame.These should be installed by Mercedes Benz or
another good service center like mine. www.starmercedes.com
. Sounds like
you do some maintenance on your own. You might consider buying some oil
filters from me on my web site www.benzstuff.com
Let me know what happens,
I will add you to the benzdoc website. Thanks, JON URNESS
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Sent: Friday, January 18, 2002 8:22 PM
Subject: Update: SRS Light on 1994 E320
Hi again Jon, I took my E320 1994 to the MB dealer today.
Thanks so much for the good advise. I was able to asked a
few questions and get some information using the initial information you gave me.
Here is the latest:
The dealer ordered a Control Module for the vehicle. They
checked the wires for a few hours. The Tech stated that
the wiring and power was fine going to the CM, but could
not confirm the condition coming from the CM. He
stated that at Pin# 6, there seemed to be a problem. He
also stated that in 1994 that the diagnostics was not
detailed enough to pin point that the CM was the problem.
Does this sound right?
The Tech stated that he could not guarantee that a new
CM would fix the SRS. He stated that the next step
after replacing the CM was to continue checking the wiring, wire
over wire.
I asked as you stated, about the CM going bad from too
many hits on the CM. He stated that he did not think it
was this type of a problem. Although he did not check the
control rings and brushes, he stated from the code he got it did
not seem to indicated that they were the problem. I should have
asked for the code, and will Monday morning.
Previous background:
I bought the car a month ago with the SRS light on. The
owner said that it was hit on the right side and that MB did the
fix. The car was serviced at MB regularly from the
records. The silver paint job appears to be high
quality work. I have seen many bad paint jobs too.
Question:
What else can I do but, let them change the CM? If I still
have the problem after the CM replacement, do I let them
continue to check the wires? What should they look for?
Thanks so much, it is so nice to have someone to ask so at least
I can understand the problem.
Thanks again,
John
- Do you have a fax #? I will fax the
diagnostics over to you. I just bought a new Dell and loaded it with info. I
can fax you all the diagrams service info , recall info galore. I will send
you what I have on the SRS system and codes. It should only take a few
minutes to diagnose the system.. Don't let them plow you on the labor. I
don't trust the "dealers" to much. Once and a while you will find
a good one. If the Tech is not getting a reading on pin 6 then how did he
know that he did not get a code from the steering? There are rebuilt control
units available. I could get you a price on one, but they are not returnable
due to the liability. Some cars are not always cut and dry, sometimes a
little back ground on the car helps and the repair is not always easy. Maybe
the car has some kind of wiring problem. Not likely. The reading of the
codes is cut and dry. If he is not getting a code pulse from the control
unit, it needs to be replaced. Then you have time to see if the light comes
on again. If the control unit gets replaced, have them do the contact rings
and brushes. Most dealers won't let you install someone else's parts, so
getting your own control unit may not be advisable. What part of Michigan
are you in? How far are you from Michigan City? Star Mercedes is
located near Rt.47 or Yorkville ILL about an hour and a half from there. JON
- Hi Jon, again thanks for your input. I know you are very busy and I thank
you for your time.
You were correct it was the Control Module. I asked them again if
the CM was giving pulses, they said it was not.
I did not ask them to change the contact rings and brushes as you
suggested because I just wanted to get my car the heck out of the dealers
control. I have to find another place to get this thing fixed when I
can't do it.
Question: Should I replace the control rings ASAP? I do wonder if I
can replace them, when I buy the repair CD, or do I need special tools.
The SRS light does goes on after initial start up for about 2 seconds. My
guess is that is some sort of self diagnosis.
Thanks again,
John
- I tried to fax you today but it would not go
through. The Replacement of the contact rings and brushes can be done by
you, if you are at all inclined in the mechanical sense. I would
suggest having the service CD on hand and review the info first. It may not
need brushes, just the rings but I would suggest doing both anyway.
The job is kind of a pain, you have to remove the panel below the dash,
steering wheel and turn signal arm. Phillips screw driver, 8 mm nut driver
or socket, 10 mm 1/2 allen socket etc.... Once the wheel is off then
you have to disassemble it to replace the rings. The phillips screws that
hold the brushes down are really tight so have a brand new screw driver
ready and don't strip them. Are you a member of the MB club? You need to
join. There is a wealth of information there. You will get the magazine among
other benefits. The reason I ask is that you can contact other MB owners in
your local group, that often helps find maybe a tech working at home, or a
good place for service other than the dealer in your area. What did the
dealer get for the control unit? The # for the MB club is 800-637-2360 my
sponsor # is U000230. JON
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