Mercedes OM617 Diesel Glow Plug Relay Wiring Schematic Diagram
 

Here is the wiring diagram for OM617 Mercedes diesel glow plug relay box when doing a swap. See attached Attachment 17806 :humm: Hope this saves the next guy some time!

Also check superturbodiesel.com - tuning performance turbo diesel mercedes, W123, W116 and up. OM617, OM60X for more info.

Very helpful, thanks!

Red - Positive of Battery (no fuse is needed)

That goes against everything I've every been taught. If I want to go crazy and add a fuse, how many amps do the glow plugs pull?

Red w/black stripe - Energize the relay (ignition switch "ON" position).

So as long as the switch is on, there is power to the glow plug relay. I assume the glow plug relay must somehow measure the amount of time the glow plugs need power vs the block temprature and cut the power off to the glow plugs once this temprature is met and/or the engine starts? When pulling an OM617 from a donor vehicle, where is the glow plug relay located (mounted to engine or elsewhere) and what provides the relay the temprature info for it to determine how long power should be supplied to the glow plugs? Is there a temprature sensor for this that must also be saved?

The relay for the OM617 takes care of the timing,IIRC.It is rated for 50 amps.The power circuit to activate the relay is only 3 to 5 amps.The relay is located on the driver side fender well.You are correct on the operation of the relay.Benz didn't use a fuse on the relay.If you're pulling everything,get the wiring for the glow plug relay system.That way you will know how everything is wired.

Unfortunately www.superturbodiesel.com is temporarily shut down.There is pics of the relay and directions on how to wire them in.Should be back up in a couple days.

There is a fuse,it is the flat piece of metel betwean the two srcews at the top or right of the relay box depending on were you are standing when you look. The relay is the first box on the fender behind the driver side head light.

https://mercedessource.com/node/8580

What are your opinons on this option? Would certainly simplify things and make 1 less thing to worry about in a repower.

Just a Ford starter relay and a timer.Probably $20 - $30 in parts.There was a write up on doing that conversion on peachparts forums or superturbodiesel forums.Can't remember which.

Yea, Ford starter silanoid (sp?).

Do you have an opinion on whether this would be a good choice when transplanting the OM617 into a different vehicle? Would allow you to ditch the whole GP system/sensors. Is the timed system worth the extra trouble to keep it going?

another nice ford starter relay glow-plug solution :
vincewaldon.com - HOW-TO: Pimp your glowplug wiring

I'm leaning towards maybe adding a buzzer :)

In an off road vehicle,I believe it would be a little more robust.IMHO

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I wish there was a timer or someway to make it like the factory set up.My GF would be driving my rig from time to time.So I will try to adapt the factory set up.

Did you use this method in your toyota repower? Is the buzzer to indicate the GP's are engaged? How do you determine the length of time required to power the GP's - trial and error?

The Benz system has a timer that turns the GPs and light on with the key.After 30 seconds the GP relay is shut off and the light goes out.Turn the key to start.

Thanks Ben, but I was inquiring how Manny wired his repower or if he kept the MB system.

I didn't realize the MB system kept the GP's on for 30 seconds, thought it was variable depending on the engine temp?

The MB system sounds preferable in theory, but it is more complicated. When I performed the compression test the insulation on the wires to the GP's was brittle and cracking and will need replacement before the motor transplant. While the MB system is currently working in the donor car, in my case its 29 years old. It appears to have a relay that adjusts the GP powering duration based on engine temp which has to come via the MB temprature sending unit. I was planning to replace the MB sending unit with the comanche sending unit so that the existing jeep temp guage would work. Don't know the particulars of how either sending unit works (ohms), but its not likely the jeep temp guage will work from the MB sending unit. I suspect replacement of the MB GP relay switch is not inexpensive when it does finally give up the ghost. Somehow, the MB system is also tied to the key switch which will also need to be adapted to the comanche switch along with installing the dash light and buzzer. For me, I'm attempting to use the KISS theory whenever possible as I'm not that smart.

Ditching the MB system for a simplified system with a single button and a cheap starter silinoid sounds pretty simple?

Relay glow-plug circuit is yet to be installed :P
Currently in the middle of my swap, and have a few other issues to address.

The addition of a buzzer, is because I was thinking of utilizing a toggle switch.
Seemed like a better idea, then holding a momentary switch.

The link also references individual LEDs (also on the list)...don't know if anyone caught that.
Individual glow-plug failure indicators are also a good thing :)

I am using the Benz relay in my Cherokee. It was simple to hook up, heavy guage wire to 12v hot all the time, one wire to 12v key on and one wire to a dash light. I used one of the red lights on the left side panel(the one where the 4x4 indicator is) that wasn't being used. The light stays on for about 5 sec or so, then start. The relay keeps power to the glow plugs for a little longer while it is running, to help the burn until it gets warm. If your motor is healthy, it doesn't take much glow time.

So, I take it that the relay is the timer.In that case,the factory relay could be used to power the starter solenoid.Take the load off the Benz relay and it should,in theory,last a lot longer. :tu:

FTE - Thanks for the info as I wouldn't have thought the GP's were designed to stay on after initial firing. How did you hook up the Cherokee's temp guage as I'm assuming the MB GP relay system must use the MB temp sender to determine the motor temp and adjust the length of time the GP's are powered? Have you gotten the cruise, tach, or oil pressure working yet? How about A/C?

Ben - Great point about removing the load to a starter solenoid. Also, you would be set up to bypass the MP system in the future if it eventually fails without having to purchase expensive MB relays

Manny - I could never be comfortable with a toggle switch no matter how many warnings were attached to it. Still a chance I could accidently leave it powered on by bumping it while existing the vehicle or simply my mind wondering. A button would be much more fail safe to me.

good advice on the toggle...

thanks

I took the Benz temp sender and drilled out the guts, then tapped it out with pipe thread to match the jeep sender. IE, I turned the Benz sender into an adapter, did the same with the oil sender. The relay is not hooked in any way to a temp sender, although there may be something inside the relay that senses ambient temps, it seemes it does stay on a little longer when it is cold outside. I am not using a tach, but was going to graft in the Benz tach into my dash until I learned the amp was bad. I have a/c but haven't hooked it up yet, due to the fact that I will need to use a custom radiator to make room for the condensor, it may never happen even though I fabbed all the mounts and brackets for the compressor.

Did the Cherokee not come with a/c or did you not re-use the 4.0 radiator?

You put the oil cooler in the bumper right? Did you consider using the MB radiator and placing the oil cooler beside it like in the MB donor car?

The MB tack in my donor is working. What did you think it would take to put it in the Cherokee dash? Sure would like to figure out how to make all the jeep guages work with the MB motor.

I think the cruise on the pre '91 xj and mj with the mechanical speedo is independant of the engine computer and will work by simply adapting the throttle control cable from the servo to the MB throttle linkage.

What did you do for throttle linkage?

Try this thread for some cruise control info. OM617.931 cruise control ....possible??

Ben - thanks for the link.

I'm pretty confident the stock cruise on my MJ will work with the repower as I believe it to be independant of the gasser's electronics. Its my understanding in jeeps that around 1991 they switched from a mechanical speedo to an electronic speedo. The cruise with the mechanical speedo has a sensor in the speedo line under the dash that sends the speed signal to the cruise electronic control unit which activates the servo. It appears its as simple as adapting the servo throttle line to the OM617 throttle linkage and supplying vaccum to the mj's vaccum reserve.

The only tach resolution I've read about yet is to take a working tach out of the MB including the dash portion and transplant it into the MJ. I wish somebody smarter than me would figure out how to adapt the stock Jeep tach to the MB sending unit.

Have you seen anyone yet to have working a/c?

BTW, I've included your suggestion of adding the starter solenoid to the MB glowplug system into my build plan. I really appreciate your input.

My Cherokee is an 86 so it had the pre 4.0 style radiator, and yes it has factory a/c. I am using the Benz radiator and the only place I could fit it in interferes with the a/c compressor. I am using the Jeep unit, as the bulky Benz unit mounts low and would hit the p/s box. My compressor mounts above the IP, so I relocated the p/s pump as well with a remote res. As for the oil cooler there isn't enough room on the side of the rad so the bumper was the logical place. I should mention that I also replaced and relocated the p/s box giving me aditional room, plus I lowered the front cross brace to allow more air flow and room for the custom rad later down the road. As for the tach, I didn't get far enough along with it to see how much trouble it would be to graft in, but now I don't care about having a tach cause the red line on this motor is way higher than I will ever spin it so no wories. My Jeep has no cruise. I combined the two throttle linkages, The Jeep cable hooks into the Benz auto trans kick-down bracket and then I hooked it to the Benz cruise linkage to operate everything. It's kind of overkill, but in order to properly work the TV cable on my 700r4 it was my solution. It seems to work nice, but you wouldn't have to get so complicated as you are going with a stick.

FTE - Thanks for the feedback as your build thread is one that I'm drawing heavily from.

From your experience, if your cherokee had been a 4.0 and you retained the 4.0 radiator, could you have removed part of the front bracing beside the radiator and placed the MB oil cooler there?

Also had a question about your steering. You tied the front wheels together with a solid drag link and lowered the F150 steering box down for tie rod clearance. From the pictures I couldn't tell the specifics of the passenger wheel concerning how the tie rod and drag link are connected. Could you provide some more detail?

Also on your panhard bar, it appears to be modified to clear the oil pan. What exactly was the modification? Did you lower the frame mount or put a larger bend in the bar for clearance?

I don't think there is enough room on the side of the 4.0 rad for the oil cooler, even if you could wedge it in there the headlight would restrict air flow. On the steering, I mixed and matched parts to come up with my setup. The tie rod from the steering box ties into the rt side 6in or so from the wheel. I basically traded places with the two joints on the pas side. Instead of the steering drag going to the rt steer arm and the tie rod to the left side coming of 6in or so back, I have the steering drag hooked to the tie rod and the tie rod is now cross-over style. I never understood why Jeep had that style "inverted Y" on a solid axle, usually it is used with an independent axle. With the solid axle and the inverted Y the toe is constantly changing with ride height, I fixed that. On the track bar, yes I not only lowered the mount on the frame but made a few bends to clear the pan. If you are going to go with the F150 box, I am not sure the 4.0 rad will clear, but the gains you get for steering clearance out way rad choices. If you have the Benz unit try it, you may have a little different motor placement than I have due to the fact that you are going with the 5spd. My setup is not in the stock location. Hope that helps!

FTE - thanks for the response.

Make sure I follow you correctly.

The stock xj configuration has the tie rod running from the pitman arm on the steering box to the passenger wheel. The drag link to the drivers wheel ties into the tie rod toward the passenger side.

Your setup has the drag link running from wheel to wheel and the tie rod connecting to the drag link 6" from the passenger wheel?

The older solid axles I've messed with have both the tie rod and drag link terminating on the passenger wheel which stikes me as a more solid arrangement. Wonder if there is a way to modify an xj / mj front axle to create the 2 terminating points on the passenger side so that the DL and TR are not tied together?

You got it right, the reason I made the connection away from the right wheel is it puts the links in closer relation to the track bar mounts. Other solid axle rigs may have been leaf sprung, not using a track bar. You can mount both at the rt steering arm if you want, but sometimes it interferes with the rim. Some may not agree with my setup, but I used what I had on hand and it works just fine.

I'm trying to wire up my relay, but I don't have the harness for the control side.
Does anyone know which pins correspond to which colors?

I will get pin numbers on my relay and update my wiring diagram, give me a day or two. I will try to repost on here and on website.

I have heard all kinds of options on this and I have this one on my dodge works far better than the factory one ever thought of working these work are easy to install price is right buy the 69.00 one and that is free shipping because it has the block sensor and the after glow

Diesel Engine Pre Heating Kit, Diesel Engine Heating Kit, Fourthgen Automatic Diesel Engine Glow Plugs Heating Kit.

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oh 1 other thing they are out of India it takes about 2 weeks to get it and I am not affiliated with them I have just used them and will use them again when I am getting close I will be ordering one myself

I have found the Benz glow relay to work great, not only does it have after glow, but it will tell you when one or more glow plugs is bad. when the indicator light blinks, one is bad, when it fails to light (but you can still hear the relay working) two or more are bad.

Is this what your looking for?
Attachment 41811

Attachment 41812

Attachment 41813

that's exactly what I'm looking for! :c:
Thanks

Here we go on pins.
Large Red wire = 30 -Positive of battery
Tan wire = 31 -Ground
Red w/black stripe = 15 -Energize relay (ignition on)
Purple or Violet = 50 -Safety switches (not needed to run)
Blue w/white stripe = LA - indicator glow lamp on dash

Hope this helps. :rocking:

I wasnt smart enough to be signed in to see pics, looks like you got what you needed.

In my factory Benz manual, one of the wiring daig (I think for the 300 but not 300sd) the purple went to a temp sender on the head, and the other showed it going to the starting circut, to keep it energized while cranking. So I assume there is two relays depending what chassie. Mine are off the sd

Is the temp sender wired directly to the GPR? If so, I may have to find out what car mine goes to before I wire it up.

Ok, got the book out. Pre 1981 uses the coolant sender to determine the length of glow time, after 1981 it has a temp resister inside the relay to do this. It looks like the one in your pic is the latter relay, hope that helps.

0m617 help!!!!
 

Im new to this site and not really too sure if I am posting in the right spot but I recently just bought a 88' jeep wrangler as a project jeep. The guy I bought it from was attempting to do a om617 swap into it...he had all the adapters for the flywheel and the frame mounts ect. but didn't complete the install. so I was hoping someone on here could help me!!!!! I have the engine mounted in and hooked up to the tranny but have no clue how to go about wiring up the glow plug relay that came with it or the alternator?? and any other tips would be appreciated!!:argh:

This will help if you have a one wire.
OneWireAlternator


Glow plug wiring.
vincewaldon.com - HOW-TO: Pimp your glowplug wiring