Glow plugs - Going manual
 

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.

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.

http://www.peachparts.com/shopforum/...plugrelay1.jpg

http://www.peachparts.com/shopforum/2932605-post11.html

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.

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.

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?

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.

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

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

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.

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.

I got one as well, it's it in the right foot operating area. I had it wired pretty much from the battery and it goes directly to the glow plug harness. Works like a charm.

The reason for My use (the original Relay died) of the Ford Starter Solenoid is that the Volvo Diesel Glow Plug Relay is similar to the older Mercedes Glow Plug Relays that are behind the Instruement. New ones were like $250 back around 1992.

Since 1992 I have only seen one Volvo Diesel at the Junk Yard; that means you cannot go to the Junk Yard a get a Glow Plug Relay for the Volvo any time you need one.

The other Plus for the Starter Solenoid is it is made to take a whole lot more amperage then the Mercedes Relay. A Starter Solenoid used as a Glow Plug Relay will likely out last the Car itself.

I know I get stoned for this...

But why not just keep the original?

I have had no issues with mine and they are original on both my cars...

I really like to not have to do the three hand maneuver to start my car, or try to explain to someone driving my car, that you need to push this button, hold this switch, turn this key that way, turn that one that way....and touch the rear dome light...

A lot of Folks don't mind getting "Stoned":eek:

I can see it if I lived in an Cold area. The possible longevity and reliability of a 30 Year old Glow Plug relay has to be questioned if you live some place Cold.

With the Manual Switch you get to Glow as Long as you want to without cycling the Key if you wired it to do that.

Since it can be setup without going through the Ignition Switch if somthing happes to the Ignition Switch or Steering Colum Lock your Glow Plugs are still going to work.

The Manual System has simplicity and reliability going for it. On mine as an added bonus if the Starter Solenoid died I could remove the + Cable from one side of the Solenoid and apply it to the Glow Plug Wire and Glow.

Simplicity can be elegant.

True true...getting that going again...I miss it :P

I should have said, getting tomatoes pitched at me :D

Agreed, here it gets into the tens and twentys

I only glow once and then lay on the key, and the car pops right off.....but with me I have 2 gauge cables, new starters, new batteries and alternators...

So starting like the manual indicates, works great for me...let the glows heat the cylinders and then allow the starter to build the compression up..

BUT If my old school relay kick the bucket, I carry spare wire in the trunk so I can bridge the plugs...

So yes I am playing devils advocate :D

Driving a car requires brain power of a beetle. Having to use manual glow plugs forces you to exercise few more brain cells and helps prevent the Alzheimer's :)

Does the dash light for the glow plugs work with the manual relay? I think my glow relay is acting up and I don't want to buy a new relay.

Usually, no. You have a button which, when pressed in, activates the glow plugs. When you release the button, they are turned off. Your finger is the relay, so the light is no longer necessary.

Without the after glow you may get a bit of smoking. I know the afterglow sure smooths out my engine for the first 90 seconds or so when it's minus 30.

If you want a glow light it's possible to use a LED switch, which is what I did. I wasn't sure about the amps for this switch so I added a Bosch relay just to be safe.

http://www.peachparts.com/shopforum/...m-switch-1.jpg

Went manual for the shutoff too so that switch glows red.

I'd say that if what you have is working don't mess with it. But if the original system is headed for the Last Roundup (or has make it there) it's probably easier and cheaper to go with the Ford solenoid than to fix the M-B system. As said, simple is beautiful.

Dan

How did you do that?

I hooked up a switch on the dash next to the glow switch, that connects to a vacuum solenoid. Touch the switch and vacuum is routed to the shutdown on the IP which shuts down the engine. To bleed the vacuum I put a pinhole in the line to allow a quick restart. It has worked perfect for the past 55k miles. A better option however, is to use a switchover valve that will dump vacuum to atmosphere automatically. One of these days I'll switch it but for now, since it's not broke, I'll wait to fix it.

Thanks

No, not unless it is wired up to do so. If you send me your controller, I can modify it to manual control with dash glow light.

The same idea applies to your Volvo, does not matter where the controller is located. It is usually the electronic timer and temperature circuits that fail in a glow controller, not the power relay. If so, then just modifying it to manually control the power relay coil is all you need to do. A Ford solenoid is designed to handle over 300 A (for starter motors- way over kill), a glow plug power relay handles less than 80 to 100 A. A clunky Ford solenoid is crude compared to a power relay in a glow plug controller and is more prone to jamming (happened to me due to corrosion). If you factor in having to hack into the glow plug wiring and having to add a fuse, a Ford solenoid is simply not worth it IMO. It gives you nothing extra, just more work, more expense plus you cannot go back to a stock system without buying a new harness.

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.

What you need is a 3 port, 2 way solenoid valve. The 3 ports allow it to bleed vacuum when in the "vacuum removed" mode so the shut off is ready to reapply. I got mine from Peter Paul but it was a bit hard to order. If you go that way I can look up the part number.

Sometimes the instrumentation plumbing that I did in my working life comes in handy!

Dan

If you choose to use a Ford solenoid, You can wire from solenoid to each glow plug directly and not touch the harness. At the top of each glow plug remove the harness connection and then connect your own wire. So the harness is there if you choose to go back to original Benz setup.

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.

Attachment 124287

Thats the 6.2 Blazer behind, , ,

Didnt mess with the MB, however, the controllers for the 6.2 system cost about $115.00 each 10 years ago, & the blazer was eating 'em for breakfast, & I couldnt figure out what the problem was.

All about $$

I drew a sketch of the Manual System on the Volvo except that I do not have a Fuse in the system See Post 18.

http://www.peachparts.com/shopforum/diesel-discussion/183583-manual-glow-plug-timer-switch-2.html#post3384024

I'm thinking about a multi relay controller I wanna build... The plate on drivers fender is perfect for it... Feed each relay with a 20a. Fuse... Simple, and individual gps controlled individually , for redundancy...

Ford solenoid is a Wells part number F492 available from any local parts store.

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

Hi Guys, I'm a little confused (and late to the party). The stock W123 Glow system does have a 'manual' mode. When things are cold out, I simply turn the key to "On" and then just wait for as long as I want, up to 30 second timeout. I don't understand what problem is being solved here.

Check out how the W123 glow plug relay works... https://www.youtube.com/watch?v=6BAgO0ZR54U

Sincerely,

Packman

If you don't have a problem, I guess there's nothing to solve....nothing to see here anyway.

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.