Pagoda SL Group
W113 Pagoda SL Group => Electrical and Instruments => Topic started by: clunker on November 07, 2018, 02:30:54
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1. There is an un-connected two-pin plug hanging down, up under the dash just above the clutch pedal - it has been like that since I have owned the car (see pic).
I can see no obvious open socket under there. The plug is on a wire that joins the main harness and appears to go through the firewall. The connector is a K 9622/1 with two identical light green wires, with no differential markings or stripes. I have scoured the all the wiring diagrams, but not see anything obvious.
Any ideas what it is for / should be connected to? I do not think I have anything that is not functioning that could explain it. (No radio - but had one at delivery. No AC - I removed it.)
2. Does the throttle micro-switch serve any purpose on my 1969 280SL manual/4-speed US-spec? (see pic)
Thanks.
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There appears to be a missing clutch pedal switch.(circled) This, and the microswitch in your other photo are 2 of the control inputs for the Fuel Cut circuit/ solenoid on the injection pump. If the pump was replaced with a later model then these are no longer used. Check the back of the injection pump for 2 solenoids.
It is possible these were disconnected because of a drivability issue. Usually faulty transmission 3rd and 4th linkage switches or a lazy solenoid.
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Yes, good catch - there is no clutch switch at all, see clearer pic of top of pedal arm.
There are two solenoids (both wired up) on the back of my FI pump, model PES 6 KL 70 B 120 R20 Y - see second pic.
So is set up ok (no clutch switch/ 2 solenoid) as is? Or should address clutch switch and/or disconnect throttle micro switch?
Thanks.
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With the clutch switch missing the circuit is non-functional. Each switch is wired in series so if any one switch is faulty or missing the entire system is inop. You could try installing a new clutch switch but be prepared to find other issues with the circuit. The only thing this circuit does is cut fuel to the injectors when you are decelerating in 3rd or 4th gear. It was more of an emissions setup than anything else.
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Thank you again - that is exactly it. I will leave it as is (but label the loose plug), leaving solenoid and throttle switch wiring in place as the circuit is fully open anyway.
Given your explanation I did do a further forum search and found this informative thread (if anyone else happens to search the topic and finds this useful) -
https://www.sl113.org/forums/index.php?topic=3277
I also attach the Haynes/p77 diagram of the circuit you described, also for other's reference.