Mercedes-Benz Forum banner

1 - 20 of 20 Posts

·
Registered
W108 1967 and 1968 Mercedes 250S
Joined
·
19 Posts
Discussion Starter #1
I have a 1967 W108 250s project going on. It came to me with much of the wiring and relays disconnected, and the Haynes manual wiring diagrams suck. Does anyone have a GOOD wiring schematic for everything under the hood and/or would someone be kind enough to post some under-hood pictures (or video) that I could look at to try and figure out where this huge bowl of spaghetti goes? I would really appreciate it.
 

·
Outstanding Contributor
450slc5.0cab 280sl5sp 280se4.5 500se+500slAMG +250seStkW108 350sl4spdX3 500secEuro
Joined
·
22,331 Posts
I am parting out a 1969 280s, and assume both cars have zenith carbs and would be similar. I don't think I've cut any wires yet, so hopefully I can help next time I go to the car.

Continuing the search for correct wiring diagrams is smart.
 

·
Outstanding Contributor
450slc5.0cab 280sl5sp 280se4.5 500se+500slAMG +250seStkW108 350sl4spdX3 500secEuro
Joined
·
22,331 Posts
I am going to upload all the engine bay shots I have from my 1969 280s. Please take them with a grain of salt.

ImageUploadedByAutoGuide1439995301.467653.jpg
ImageUploadedByAutoGuide1439995318.601780.jpg
ImageUploadedByAutoGuide1439995344.217582.jpg
ImageUploadedByAutoGuide1439995369.451485.jpg
ImageUploadedByAutoGuide1439995388.750861.jpg
ImageUploadedByAutoGuide1439995411.400926.jpg
I removed the distributor cap and wires myself. But this is the current condition.
ImageUploadedByAutoGuide1439995429.251421.jpg
ImageUploadedByAutoGuide1439995479.700803.jpg
ImageUploadedByAutoGuide1439995496.517525.jpg


That's everything. I've got right now, but can take detailed pictures of any area needed at a later date.
 

·
Registered
W108 1967 and 1968 Mercedes 250S
Joined
·
19 Posts
Discussion Starter #4
Awesome. I appreciate the help. My main area of concern is on the passenger side fender near the firewall. There are a bunch of relays mounted there and I've no clue what any of the wires from them go to. Beyond that, pretty much all the wiring on the passenger side coming from the wiring harness. ... not a clue what any of it goes to. So any help anyone could offer would be awesome.
 

·
Registered
1967 W108 250s
Joined
·
83 Posts

·
Registered
W108 1967 and 1968 Mercedes 250S
Joined
·
19 Posts
Discussion Starter #9
OK, so here's what I got going on. I got all of these hanging from wire from the hood to keep them up and out of the way. On the plate, to the far left, is some sort of fuse box with no fuses in it. To the right of that, there is some sort of relay. Below both of those is some other sort of relay. On the far right, hanging by itself is another relay of some sort. I think it might be a part of the charging system maybe? Any clues what these are and what they go to? And to the right of that, I have a wad of wires rolled up that come from the wiring harness. I think maybe these might go to the carburators??

:confused:
 

Attachments

·
Registered
W108 1967 and 1968 Mercedes 250S
Joined
·
19 Posts
Discussion Starter #10
Here's another quandary. I got these 4 pigtails that come out of the firewall close to the master cylinder. Any clue what these are for?
 

Attachments

·
Registered
W108 1967 and 1968 Mercedes 250S
Joined
·
19 Posts
Discussion Starter #11
Last question of the night (I hope); When I got the car it had no AC. The blower had been removed, most of the wiring, and the main wire that goes to the blower is gone. Now, my main question is, I'm sure that the dials operate as reostats, but do they work off of a positive or negative?

I know some blowers/reostats operate off of the idea that as you turn the dial it increases the voltage, hence the fan speeds up. In that case I would need a power wire coming from (I assume) the Thermo King unit under the dash? But from where? And in such case, I assume the ground from the blower would just go to the body?

On others, the blowers/reostats work off of the ground, so that as you turn the dial the ground increases and speeds up the fan. In such a case, there would have to be a ground wire coming from the Thermo King going to the blower (I assume, but from where?), as well as a constant 12v power source when the ignition is in the on position (but from where?).

Right now I have a power wire supplying the Thermo King underdash unit, and then a blue and and orange wire going out through the firewall (which are cut off a few inches after they enter the engine compartment). From trial and error, it looks like the orange supplies the voltage out, and the blue is a return wire back to the unit? Those are the only three wires I can find coming from the under dash unit.

Man, this is a mess without a good wiring schematic!!! :surrender:
 

·
Registered
W108 1967 and 1968 Mercedes 250S
Joined
·
19 Posts
Discussion Starter #12
I have the same car 67 250s
ill click some pics of the relay center this evening

a couple of months I posted a thread on fog light installation there are a few photos in that thread
http://www.benzworld.org/forums/vintage-mercedes-benz/2287457-w108-foglight-wiring-3.html

I can trace wires if needed just load some pics of wires in question
Well, the picture you posted (shown below) appears to be the same fuse box and relays I have, but none of this crap is hooked up to anything. If you can tell me what these all go to I would be very grateful!
 

Attachments

·
Registered
1967 W108 250s
Joined
·
83 Posts
Here's another quandary. I got these 4 pigtails that come out of the firewall close to the master cylinder. Any clue what these are for?
wondering what transmission your car uses
on mine which is an automatic there is a wire feed that connects to the shift linkage those are the wires to the left of the master cylinder. there are two more wire feeds that run along the fire wall that start at the right side of the master cylinder (firewall) it looks like you only have one so the stray wires might run there one set goes to the starter and the other to the relay bank those look like pretty heavy gauge wires so i might push to say they belong to the starter. if the starter has wires already then i dont know.

on the relay tray the fuse block has red wires that go on one side and the other side powers the relays depending on your accessories the amount of relays will vary

i would also agree the bundle of wires looks like the carburetor wire feed
 

·
Registered
W108 1967 and 1968 Mercedes 250S
Joined
·
19 Posts
Discussion Starter #15
Any clue what those relays take care of?

This car was originality equipped with an automatic transmission, with the shifter on the floor. The wires in question by the master cylinder went down by the transmission, but are not hooked to anything.
 

·
Registered
1967 W108 250s
Joined
·
83 Posts
My car is equipped with the trans shifter on the steering column. So the wires probably run a lite different but at the linkage they connect with a male female plug the same plug that benz uses thru out the car
I can't load photos. Right now.
I will check into the relays
And look over the wiring schematic I have.
Looks like somebody removed a lot of wiring then lost interest.
 

·
Registered
W108 1967 and 1968 Mercedes 250S
Joined
·
19 Posts
Discussion Starter #17
Yeah, someone started the project on this car, then was like "Meh"..... I got it at a good price tho, and I love it, so I'm willing to see it through. Just need a little help here and there figuring out what the heck goes where. Getting very anxious to get it back on the road.... getting so close!
 

·
Registered
1967 W108 250s
Joined
·
83 Posts
So I had a little time, and did a little searching looks like the tray of relays is pretty much for the electric windows and the AC the one for the AC is connected to the starter so it only works when the car is running. The further most relay front of car is for the electiv windows. My car has more than two so I've got a little more searching to do but I hope the info sheds some light.
 

·
Registered
W108 1967 and 1968 Mercedes 250S
Joined
·
19 Posts
Discussion Starter #19
So I had a little time, and did a little searching looks like the tray of relays is pretty much for the electric windows and the AC the one for the AC is connected to the starter so it only works when the car is running. The further most relay front of car is for the electiv windows. My car has more than two so I've got a little more searching to do but I hope the info sheds some light.
Interesting. The front relay must be for something else on my car, since it doesn't have power windows. :confused:
 

·
Registered
Joined
·
2 Posts
I have a 1967 W108 250s project going on. It came to me with much of the wiring and relays disconnected, and the Haynes manual wiring diagrams suck. Does anyone have a GOOD wiring schematic for everything under the hood and/or would someone be kind enough to post some under-hood pictures (or video) that I could look at to try and figure out where this huge bowl of spaghetti goes? I would really appreciate it.
Greetings from the future! Five years later with a similar car in the same predicament I came across this thread. Wondering if the OP ever found any useable info/legible photos for reference? Not having much luck anywhere else on the interwebs.
 
1 - 20 of 20 Posts
Top