[R129 SL] Soft Top and Roll Bar Indicator Lights On - Soft TopControl Unit

[Peter S]

Hi Jody,

With electrical and electronic failures, the mileage has very little to do 
with the failures!  In fact in the older circuit configurations of the 
electronic 'goodies', corrosion/corrosion oxidisation, and capacitors 
'drying out' are the main causes of failures.

I actually pull apart the electronics and try to fix them.  Many of the 
older parts have discreet components (transistors, resistors, some mini 
chips etc) so I have fixed most of the parts myself (unless the vehicle is 
under a limited warranty).   At the moment, I am repairing a 'flasher unit' 
for my 1983, W123 .  While I have some spare parts for most of my Merc's, I 
like to find out the reason for failures, hence the inquisitiveness.   The 
Flasher unit has a dud transistor and a dud capacitor - just have to replace 
them and the parts cost me about 20 cents 15 years ago. A replacement 
flasher is about NZ$300.

If you have a circuit board out at all (or the auto electrician has it 
out!), spray the circuit board with CRC Zone 240.  This is good stuff and 
limits corrosion.  Note also that corrosion also occurs on plugs and 
sockets, so these also need to be maintained. True also for your fuse 
connections.

I have repaired 2 x central lock controllers - reasons for failure - 'dry 
joints' (poor soldering by the manufacturer). Cars had travelled less than 
35,000 miles!!!!  MB contract out all this stuff and Bosch do a fair bit of 
manufacturing for MB.

Note also that window switches fail as well.  There are only about 7 parts 
in each these switches, I have accumulated a lot of old ones, so I fix these 
for people if I have the exact bits - and if they are club members!  Easy to 
repair and saves a heap of $$.

So Jody, sometimes mileage has little to do with electrical and electronic 
failures as atmosphere takes it's never ending toll on metallic parts.

Well, getting colder in good old New Zealand as we are now in Autumn.  21 
degrees C, 2 days ago and now it is 8 degrees C.  Nearly time to put on a 
jersey!!!  Easter Thursday here, so a full weekend is planned with Easter 
Services and car/ motorcycle events.

Have a good one wherever you are in the world.

Regards, Peter S.





----- Original Message ----- 
From: "Jody Techlin" <starfishsailor at mail.com>
To: "Deneal S" <deneals at sbcglobal.net>; "Rolfe" <seitle at whidbey.com>; "SL 
LIST" <r129list at mbcoupes.com>; <jimc at windwireless.net>; 
<mercedes at mercedesmailinglist.com>; <simssj at gmail.com>
Sent: Thursday, April 09, 2009 9:23 AM
Subject: [R129 SL] Soft Top and Roll Bar Indicator Lights On - Soft 
TopControl Unit



> Hello All,

> The mechanic called this afternoon with the reason why my 1996 SL320's 

> roll bar light and soft top activation button light are lighted.  In my 

> case itr is the soft top control unit which has failed.  This just so 

> happend to coincide with when I had the car detailed but the detailer had 

> nothing to do with the units failure.  The trusted shop I use shopped for 

> the part, if we purchase the replacement part from the MB dealer network 

> it is $2100; if purchasing a remanufactured unit with the same 1 year 

> unlimited mileage warrenty the price is $925 so needless to say we are 

> using the remanufactured unit.  I am surprised the original unit failed 

> with so few miles on the car but age is age I guess. I would like to thank 

> the many people (Daneal, Jim, Rolfe, SJS and others) for their assistance 

> and advice. I was hoping the problem would be much less costly but I guess 

> that's the way the cookie crumbles sometimes. Thanks again one and all.

> Best regards,

> Jody

> 1996 SL320, 29k

> Punta Gorda, FL

>

>

> -- 

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