Author Topic: Module under battery tray  (Read 5311 times)

Reischmann

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Module under battery tray
« on: December 24, 2012, 20:54:24 »
I have recently purchased a 1970 280SL.
While replacing the battery, I noticed a module mounted to the underside of the battery tray, that is unplugged.
It has three pins and looks like it is wired into the factory harness.
Any body know what this is?
Car seems to run fine with it unplugged.
Thank you.

Jack Jones

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Re: Module under battery tray
« Reply #1 on: December 25, 2012, 16:21:09 »
This is the original electronic ignition module used on 70-71 cars. Many owners had them bypassed and converted back to point ignition when the module failed but left everything in place.
Jack Jones                                                                                                   
1970 280SL 4 Speed
1984 280SL 5 Speed

ja17

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Re: Module under battery tray
« Reply #2 on: December 25, 2012, 17:42:37 »
Hopefully they changed the ignition coil and ballast resistor when they by-passed the electronic ignition module otherwise,  the ignition will pit and burn the ignition points in a short amount of time. Check to see if you still have an original blue Bosch coil. It may still have a tag on it indicating it is for transistorized ignitions.  

If you now have a transistorized coil, change to a Bosch non-transistorized ignition coil with the correct ballast resistor. I believe the Bosch red coil with a 1.8 ohm red ballast resistor is what is currently available and correct for non-transistorized ignitions. Otherwise find a good transistor box and re-connect the original ignition with the blue transistorized ignition coil .  
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

hands_aus

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Re: Module under battery tray
« Reply #3 on: December 25, 2012, 23:15:10 »
It might have a pointless system installed
Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL #114, auto, ps , 717,717
best of the best

Reischmann

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Re: Module under battery tray
« Reply #4 on: December 27, 2012, 21:22:18 »
Thank you for the quick replys.
Will research the coil to see what is installed.
I bought this 280 SL as a surprise bithday present for my wife. She has always dreamed of owning one.
It is in good shape but not perfect.
I want to make sure that it is a reliable, fun, and comfortable car for her.
You can be sure that I will be tapping into the condiderable knowledge and experience this group has available to its members.
Please feel free to point our any weak or problem areas I need to know about.
One of the first things, is to rig a hard top lift, in our garage.
Any kits, drawings, or ideas will be greatly appreciated.
M

Russell

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Re: Module under battery tray
« Reply #5 on: December 28, 2012, 08:01:05 »
the search tool is your weapon here. try that first as there is a wealth of information. if you cant find it or dont understand what you are reading (plentiful in my case) then there are always people here that can point you in the right direction and patiently explain.

one pointer i have learnt though is dont do what you did here is ask one question about something then ask another about something entirely different in the same thread as it makes it much harder for a doofus like me to search the forum. someone might have a great answer that will be buried for good under a wrong heading.
just a thought.

Iconic

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Re: Module under battery tray
« Reply #6 on: December 28, 2012, 13:46:09 »
In addition to Russells very good points, in the long run, it will make it easier for us to help you if you put your year and model in your signature line (I know it is a 280, but you might not mention that in the next thread). Take a look how others have done it.
Enjoy the ride !!!
1970 280 SL Automatic, USA version, Grey-Blue (906G/906G), Blue leather (245)
1968 SS396 Camaro Convertible (owned since 1977 -- my first car :D)
1984 Porsche Euro Carrera coupe, LSD, SlateBlueMet/Blue
1998 BMW M-Rdstr Estoril Blue
1970 280 SL Automatic, Anthracite Grey-173G, Red Interior-132 - sold

Reischmann

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Re: Module under battery tray
« Reply #7 on: December 28, 2012, 16:09:49 »
Good advice.
Thank you,
Mike
1970 280SL