I would like to convert the glow plug system on my 1980 - 300D to manual. I did a search on this site and found that some folks have done that. They have used a Ford solenoid. Is there a part number for that and where can I buy one? Also a schematic of your design will be greatly appreciated.

__________________
1980 - 300D
1984 - Mazda B2200 Diesel

Any Ford starter solenoid will work. Easiest thing is to just go out the junk yard and grab one off almost any Ford product. They're usually on the fender well right out in the open.

Run the field through a switch in the dash - MOMENTARY TYPE. Run the other side to the glow plugs through a 80 amp fuse from the battery, or a junction box in the engine bay.



Glow plug relay: the opposite problem.

__________________
Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

I have an interesting problem of the same type:

My 1950s 170 SD did not come with glow plug controller, which is manual and very hard to find. The only seller who are the relatives of a guy famous for overcharging and now deceased, want 400 for the set-up, but " original but used, no guarantee it works, no return."

So I am looking at creating an entire glow plug control system. The original was series but hey, why not make it parallel, since I am starting from scratch?

I'll be following any developments closely. Especially interested in part numbers of components and gauge of wire for everything here, expect that nothing is probably less than #4 gauge.

__________________
Strelnik
Invest in America: Buy a Congressman!

1950 170SD
1951 Citroen 11BN
1953 Citroen 11BNF limo
1953 220a project
1959 180D
1960 190D
1960 Borgward Isabella TS 2dr
1983 240D daily driver
1983 380SL
1990 350SDL daily driver alt
3 x Citroen DS21M, down from 5
3 x Citroen 2CV, down from 6

I have a 1950 170d and it does not have any controller at all. Theres a lever on the dash by a small cup with a hole in it. Turn the lever down "half way" and hold till you see the coil in the 'hole-in-the-cup' glow red, (it appeares to be just the coil from a glow plug), then, turn the lever down all the way to start the engine. Turning the lever 'up' shuts off the engine.



Thats the 6.2 Blazer behind, , ,

This is what I did on My Volvo Diesel as far as the Solenoid Hook Up.

Older Fords did not have a Solenoid mounted on the Starter itself as GM/AC Delco and your Mercedes do.

If you look pick something like a 1968 for Falcon or the like and search for Starter Solenoid you will see what it looks like.

I just trolled the Junk Yard and pulled one off of a random Vehicle.

Ford also has a smaller Solenoid that is for the Ford Diesels that is not a sufisticated Relay like the Mercedes.

I posted a crude drawing of the system like 6 Years ago but have no idea what thread it was in.

I believe you need an Switch that is only on as long as you hold the switch down. If you use another type of switch you may forget and leave the Glow Plugs on.

Also in My particular case I am not connected to the Ignition Switch and am connected directly to the Battery.

I believe it is possible to use the Wire from the Ignition that goes to the Glow Plug Relay to turn the Solenoid on. But, I did not do that.


Picture:
I did not color Code the Wires.
The Selonoid has 2 Large Terminals.
One Terminal larger Terminal needs to be conected to the + Battery and the other large Terminal is going to go to the Glow Plugs at the point where the Wire is still a single wire you might want to install an 80 amp Fuse.

You are going to need to Wire one individual Wire for each Glow Plug and attache them to the Main Line or use a Wire Terminal/Junction Block.

In the pic the Green Wires go to the Switch. One Green Wire is connected to the + Large Terminal that comes from the + Battery and it goes to the Switch and back to the Solenoid "S" Terminal.

The only other part if the Circuit is that the Frame of the Solenoid needs to be grounded to the Chassis.

Attached Thumbnails

 

__________________
84 300D, 82 Volvo 244Gl Diesel

There is no need to use a Ford solenoid on a Mercedes. Just use the power relay inside the Mercedes glow controller and treat it as the "Ford solenoid". Open up the controller, identify and isolate the traces to the coil of the power relay, one side of coil goes to ground, the other goes to +12v via a momentary push button switch, unplug the small 4 pin connector and you are done! No need to hack up the wires to the glow plugs and tie them to the Ford solenoid! This way you can always go back to a stock Mercedes system by buying a new glow controller since you have not hacked up the glow plug wires.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

So you are saying run a thin wire from the battery to a switch on the dash and from there to positive side of the coil?

__________________
1980 - 300D
1984 - Mazda B2200 Diesel

Yes except I'd run it from switched +12 and not from battery, and make sure the other side of the coil is grounded. and don't forget to unplug the small 4 pin connector before testing.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

IF (and that's a big IF) I find that mine won't start I intend to go with the Ford solenoid system as diagrammed. Nothing wrong with that - those suckers are TOUGH! And good for like 1M amps (I'm guessing here). The S-10 will never be asked to start in the winter unless it's in the shop so I don't expect much of an issue but IF........

I'll use another starter button to apply the power. Mine (the one in the truck for the starter) is from Speedway Motors, a GREAT source for all kinds of race car parts including electrical bits.

Dan

funola,
When you say make sure the coil is grounded, is it grounded normally or is that something I"ll have to do myself? If so how. Not good with E-gremlins.

PR

Some are and some are not. You'll have to check. If you're not good w e-gremlins. I have one already converted for $40 + shiping. Comes with a 1 year warranty.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Thanks. What and where is "switched +12" ?

__________________
1980 - 300D
1984 - Mazda B2200 Diesel

Any point in the harness that only gets +12V when the ignition is turned on.

I suppose that this helps ensure that your switch for the glow plugs can't run the glow plugs when the car is off, say if you accidentally let something lean on it or it gets stuck.

__________________
1979 300D 040 Black on Black - 1985 300D Maaco job (sadly sprayed over 199 Black Pearl Metallic) on Palamino

http://i.imgur.com/LslW733.jpg

The Baja Arizona Oil Burners Send a message if you'd like to join the fun
Left to Right - UberWasser, Iridium, Stuttgart-->Seattle,, mannys9130

Visit the W123 page on iFixit for over 70 helpful DIY guides!

As long as you have 15 amps or so (look at the rating of the fuse) you can catch it anywhere that does NOT have power with the key off but does have power with the key on. It's a safety thing so that you can't possibly have power to the glow plugs with the key off. The wire from your 12VDC source will go TO the momentary switch (either terminal) and the other terminal will go OUT to the "switched 12VDC" as marked on the drawing.

All the solenoid is is a huge honkin' switch that's activated by a smaller voltage (the 12VDC switched) so that you don't have to run battery-cable sized wires into the passenger compartment. The Ford solenoid is really functionally the same as the Bosch unit built into your starter but Ford has long packaged them separately from the starter unlike GM, M-B and many other companies.

Dan

On my '84 6.2 Blazer, I got tired of replacing($$) glow plug controllers. I picked up power from the glow plug relay, through dash to button switch & back. About 8 or 9 "Mississippi's" in the winter.