I have a 1966 MB 250s the wires coming out of the kickdown switch to the automatic transmission are disconnected there are three wires one brown with a blue or black stripe and two brown ones the terminal on the transmission has four pins numbered 1 thru 4 .



Transmission terminal marking

1------ 81

2----- 81a

3------ 50

4-------50

Can anyone tell me how to connect these wires ?

I just bought this car and I am thrilled to death to own such
a beautiful car.


Thanks CLAY (rustfixer)

:cool:

Clay,

You're taxing my memory here. I'm also a little confused about which switch you are talking about. With four wires it sounds like you are talking about the switch on the left side of the transmission which is the neutral safety switch and back up light switch. The kick down should be a single wire going to a solenoid on the trans. You also have a solenoid on top of the trans that has 2 or 3 wires going to it. This is a K4A025 trans with no control pressure. Control pressure is controled via this solenoid which is operated by a switch at the base of the front carb. Send more details and I'll see if I can help. My first MB was a 68 250S.

Peter

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Peter

Thanks for the Info. this switch is on the left side of the transmission about half way up. There apperars to be 3 wires coming down from the kickdown switch which aren't connected. Where is the solenoid which is supposed to be hooked up to the kickdown switch? Also you mention that there's another set of wires which come from the front carburetor to the transmission what are these for? I'm wondering if all these wires are hooked up because the transmission seems to stay it third gear an awfully long time from about 30mph to about 75mph.



CLAY

Clay,

As I suspected you are describing the neutral safety switch which has 4 wires. To determine if this switch is wired correctly and adjusted correctly, see if the car only starts in park and neutral. Put your foot on the brake and see if it will start in drive. It should notstart in drive. To check if the backup light section is working, apply the parking brake, turn the key to the position where the battery light comes on, and put the shift lever in reverse. DO NOT START THE CAR. With the park brake set and the key on, check if the reverse lights are on. The kickdown solenoid is on the right side of the trans and has a connector for only one lead. The control pressure solenoid is mounted on the very top of the trans and controls shift pressure. The solenoid has 3 positions. As I have said you are taxing my memory here, brcause I haven't set one of these up in over 20 years. Put the car on stands and slide under it. Watch the lever on the right side of the trans while someone turns the key on. The lever should move. Have that same someone push the accelerator partway down, and watch the lever move again. Have the person go to kick down and watch the lever move a third time. Check all this out and let me know your findings so I can follow up. If you have questions about what I have explained, just ask.

Peter

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Peter
I did as you suggessed and the car would start in neutral , park & drive4. So I did alot of checking and I found that the neutral safety switch is actually under the hood right near the firewall just where the shift linkage comes through. I adjusted the switch arm a bit now the car will only start in neutral and park.Right in that same location there is a switch which has two wires coming off it I checked this also its the reverse light switch. So the only conclusion I can come up with is that at some point this car had a auto transmission change and the one that they put in was the newer type K4C 025 with the neutral & reverse switch on the transmission rather than under the hood so they wired up the one under the hood and left the one on the transmission disconnected. I also checked on the right side of the transmission there is an arm which is tied to the throttle linkage via a steel rod. I think that this is how the transmission is controlled. I haven't located that kickdown solenoid yet but at the next opportunity I am going to look long and hard for it.


I really apprecate your help without it I would nver have known that the car would start in drive which of course could have dire consequences!


THANKS AGAIN

CLAY

Clay,
Glad my input has helped you solve your problems. I forgot that the early years had the switch on the column. They just left it as was and as you figure installed a K4C025 with all the control linkage. Don't look for the solenoid on top anymore, because this trans has a control pressure rod which I believe is causing your late shift problem. If the rod is adjusted too short, the trans thinks you have your foot in it and delays the shift. Try lengthening the rod a few mm and see if it gets better.

Good luck,
Peter

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