Author Topic: 1969 280sl wiring help  (Read 223 times)

edwardburak@erols.com

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1969 280sl wiring help
« on: July 21, 2021, 21:07:39 »
 1969 mercedes 280SL USA Version automatic

I'm having some trouble installing some of the wiring for the motor. This motor is not original to the car, I am not sure of the year car it was taken out of. I bought the motor from budz-benz 10 years ago and am now installing it.

I have this 3-wire harness coming off of the main harness from the firewall on the driver's side (USA Version). It has one longer single wire which reaches the 100 degree advance on the thermostat and 2 wires that reach a connector above the injector station.

I realize that the connectors are the wrong type, my car does not have those round connectors as found on other cars, maybe someone altered it in the past.
are these the correct locations for these wires?
If so, I will try and source the correct connector to splice into these wires
thanks for your help

edwardburak@erols.com

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Re: 1969 280sl wiring help
« Reply #1 on: July 21, 2021, 21:17:20 »
I also have this connector on the side of the throttle body, I do not know what it is called.

Are my wires on this connector correct. they also stem from the larger loom, coming from the firewall.

This was the logical location with the bends in both the connectors and the wires

thanks for your help

edwardburak@erols.com

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Re: 1969 280sl wiring help
« Reply #2 on: July 21, 2021, 21:23:16 »
another connection that I am unsure if I have correct is the solenoid or relay beside the fuel throttle linkage overtop the intake.

my placement of these wires on this connector was also a use of the process of elimination and a reasonable location.

I have not found another location that these wires could go

the near side wire is green and the far side is black with a red stripe.

Are my guesses correct?

if not, any help would be appreciated
thanks

edwardburak@erols.com

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Re: 1969 280sl wiring help
« Reply #3 on: July 21, 2021, 21:26:05 »
I have this fuse box on the passenger side (USA Version) beside the radiator overthrow reservoir.

I have wires that are dangling and I assume go here; I have not been able to find a diagram on it, could someone please send a photo of theirs with the wires exposed and I will make the correction my own.

thanks for the help.

edwardburak@erols.com

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Re: 1969 280sl wiring help
« Reply #4 on: July 21, 2021, 21:29:01 »
this is my last issue, I have another fuse box on the driver's side beside the brake booster.

am I missing something in this box?

or is the extra slot just for modifications and additions?

thanks for the help

Pawel66

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Re: 1969 280sl wiring help
« Reply #5 on: July 22, 2021, 07:40:35 »
Let me give it a stub.

1. Fuse box on the passenger side, near the voltage regulator - is for the radio and the power antenna if you have it. Two wires may be coming out of the harness there - one with permanent power (antenna), one with power with ignition key in accessory position. They go through the fuse and then to the radio/antenna through a grommet in the firewall. You will find more when you search "radio wiring".
2. Fuse box near the brake booster - accessory fuse box. Designated primarily to fog lamps, but may serve many purposes (e.g. I have the dashcam power through it). Two slots for fuses - fill them as per needs. You have something hooked there, not sure what it could be.
3. Constant speed solenoid connection - the green or red/green wire is ground from hydraulic switches on the gear box sides. Provides ground when gear is engaged to make this solenoid move the linkage by about 5mm to increase idle when in gear to prevent engine from stalling. On late US cars this solenoid is for increasing idle when AC is switched on and is hooked to the AC, not gear box. On some cars it is not connected to anything. The other wire is, logically, +. From fuse 5.
4. The throttle switch - provides power to the 3 way solenoid on the gear box to make it in the upshift mode as you press the gas pedal. Red/black wire is + from fuse 3, brown/white wire goes to 3 way solenoid.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

edwardburak@erols.com

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Re: 1969 280sl wiring help
« Reply #6 on: July 22, 2021, 10:22:16 »
thank you, I will check that my wires are correct

lpeterssen

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Re: 1969 280sl wiring help
« Reply #7 on: July 22, 2021, 11:46:51 »
Dear Edward

You need a lot of help.  Go to the technical section of the pagoda forum and study the wiring diagram for pagoda 280SL.

I will try to guide you the best. Let’s do one or two related pictures at a time.

The first will be the TTS or also called Thermo Time Switch.  This device has two terminals one labeled “W” and another labeled “G”. I saw the pictures taken, and that the engine already has a modern style TTS which requires you to change the “0” shaped terminals of your cables for a modern style connector, or some aftermarket terminals I will show you the picture as well.

Here you have to be very careful with the connections since you can cause a very nasty short since this lines are one a positive signal and the other a negative. If you invert them you will have a short remember.

“G” terminal is positive and comes on the cable ROSE/blue and derives from the ignition switch T50 cranking signal.

“W”  is negative and is the trigger signal that activates the different cold start relay and mixture relay on the left fender close to vacuum booster.  That cable is ROSE.

SEE pictures.
« Last Edit: July 22, 2021, 12:41:09 by lpeterssen »

lpeterssen

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Re: 1969 280sl wiring help
« Reply #8 on: July 22, 2021, 11:56:07 »
This are the kind of terminals you need to put on the TTS cable ends.  Is much cheaper to change the terminals than buying a new original style TTS .  Old style TTS are about 300 usd.


lpeterssen

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Re: 1969 280sl wiring help
« Reply #9 on: July 22, 2021, 12:01:50 »
Now on the same loom that goes to the TTS there is a single “o” shaped connector which goes to the MIXTURE SELENOID a the back of the fuel injection pump.

Green circle on the photo.

The cable should be Black/rose

lpeterssen

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Re: 1969 280sl wiring help
« Reply #10 on: July 22, 2021, 12:12:02 »
Now Edward

Let’s go with the terminals related to the automatic transmission……

There are two elements to remark on your photos.

One is the IDDLE SWITCH which is at the INTAKE THROTTLE which receives two cables. One should be RED/BLACK (+ signal) coming from fuse no.3, and the output wire is BROWN/WHITE also (+) going to the transmission selenoid.

In here the way you connect the cables does not matter, you can invert them and nothing will change since this is only a switch.

Iddle switch is shown as element 52 on the diagram


lpeterssen

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Re: 1969 280sl wiring help
« Reply #11 on: July 22, 2021, 12:18:41 »
And finally the Constant Speed Selenoid….l. Also named CSS (element 53 on the chart)

It is fed with two cables.  Order on which you connect them also does not matter.  One is a constant 12V feed from fuse no. 5, which is a cable active whenever ignition is on, Colour BLACK/RED/GREEN.

And the negative activation signal comes from the automatic transmission pressure valve on the cable Colour GREEN/RED.

And that will be all for today….

Hope everything goes fine.

Best regards
Engineer Leonardo Peterssen

lpeterssen

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Re: 1969 280sl wiring help
« Reply #12 on: July 22, 2021, 12:22:37 »
Look at the Colour of this cable, not sure if it goes here at this thermocouple…..