124 SRS Control unit.

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MD5

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My 94 E320 cabrio went into the MD's this morning to diagnose the intermittent flashing of the SRS light. The last long trip I did about a month ago the light stayed on for the last 30 miles or so. I took it for a drive last night, and it started flickering after about 15 miles, but didn't stay for any length of time. It didn't come on this morning when I dropped it off.

They don't know if it's the SRS control unit or a wiring problem. Anyone had this before? Would the unit be the same if it was one or two airbags? Anyone have a spare?
 
Loose wire / plug under one of the seats?

Nick Froome
 
As above & pay particular attention to the red connectors and associated wires coming from the seat belt latch...
 
Thanks for the replies. I hope it's something simple. I decided to take it to the main dealer, as they were looking to make amends for a complaint I'd made in an after service survey, but they phoned prior to my first post to say they had spent a few hours investigating, and should they continue to do so?
 
Favorite places to begin looking already mentioned. I'm not really surprised but a main dealer really should be able to do better than "it might be the control unit or a wiring problem" :crazy:

Did they tell you what (if any) fault codes the SRS unit spat out? In theory at least it should store codes for various things and in some cases point you in a very specific direction http://www.w124performance.com/service/w124CD2/Program/Chassis/91-710.pdf
 
@hotrodder. No comms were coming back from the unit - no fault codes, nothing, hence the long investigation, and the belief that the unit is dead.

As an update. They phoned last Friday to say that it was definitely the control unit, after they'd had to wait for wiring diagrams to come from another branch and spent about four hours worth of investigation! A replacement unit (one left in the country) comes in at about £1260 + vat, so they ordered it on a returnable basis. Not inspired with confidence or motivated by price, I declined.

After a few emails to a technical advisor over at the official owners' club about serviceability of the unit, he pointed me to a new, genuine MB unit on ebay.de which cost me €149 delivered (bought on Saturday, arrived on Tuesday). They agreed, unusually, to fit it, so I dropped it in today, to be told it was the wrong part, because it's for a single airbag set up, which my car is.:doh:

So they've spent all that time checking the wiring, and incorrectly ordered a £1500 part in the belief that my car has two airbags, so I'm waiting to see what happens next, as they are going to fit the part I have provided. Fingers crossed!
 
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