HELP with 602 GP RELAY
 

I just acquired a GP RELAY for my OM602. Part#662 545 30 32
Anyway, there are 3 connection points: 2 connectors and a thick bolted down WIRE (which I assume is the POSITIVE terminal which will supply the plugs)
One connector has 5 thick wires coming out of it which goes to each plug...
The other smaller connector also has 5 wires coming out of it but are much thinner:
RED w BLACK STRIPE
YELLOW w BLACK STRIPE
BLACK
BLACK w WHITE STRIPE
BLACK w YELLOW STRIPE

Anybody have any idea which goes where?
Haven't applied any voltage to it yet... planning to find which one energizes the relay.

How should the relay work anyway? What triggers it? ACC/RUN? And when should it cut out? I know it does this automatically, how should I wire it?
My car used to run on GASOLINE, I changed out the engine to an OM602. It runs fine but I have to feed the GPs manually to get it to start. Hence the newly acquired GP Relay.

First of all, you need a GP relay from 602 engine. :rolleyes:

Yes... I do have GP relay from a 602. And I DO have a 602... but the car originally had an M104... it runs... I wired a switch to manually energize the relay. Would've wanted to have it function as intended. Hence... my inquiry. I found a few diagrams... following those i couldn't get the relay timer to function. No delay, no nothing. So i'm stuck with my current setup... manually engaging the GP relay... which works for me... for now.

How are you getting power to the glow plugs without full relay function?

I'm not familiar with that glow relay part number but I'll assume the connectors are compatible with MB passenger car harnesses and it's an afterglow relay. Forget the wire colors and check for pin numbers either on the relay itself or on the connector. The numbers should correspond between relay and connector pins. Here's the pin list for a 90-91 300D 2.5:

pin 1 = +12V when key switch in run to initiate preglow cycle (W124 = hot side of fuse 7)
pin 2 = +12V when key switch in start to terminate preglow cycle (W124 = NSS)
pin 3 = +12V to gauge cluster glow indicator
pin 4 = ground
pin 5 = blank
pin 6 = signal from glow temp sensor by water pump to determine preglow and afterglow cycle times

Assuming each glow plugs test between 0.7- and 1 ohm at the glow relay connector, leave pin 2 disconnected then see if you get the max preglow cycle of ~30 seconds. I don't know how the glow relay behaves when there is no temp sensor.

If this gets to be too much work, a 617 pencil type glow relay should work for you since afterglow isn't much of a benefit in the tropics if you have healthy glow plugs.

Sixto
87 300D

It is... it came from a Ssangyong Musso, which comes with a turbocharged 2.9L om602. :) Which is the same engine I installed in my w140. :) hehe

Sixto... I wired a switch to supply a positive signal to PIN1.

But the thing is... as soon as I let go of the switch, the relay de-energizes. So I have to press the switch for the duration of the cycle. (by feel :) )

I did not use the temp sensor wire as I do not think I have the wiring for that.

I watched a youtube vid which demonstrates the relay function, lights and simulated starting procedure wiring and all. :) I can't get my relay to function as intended. Anyway... as long as I can trigger the glow plugs I'm good. In fact I feel having manual control of the plugs is a plus. :)

Pin 1 isn't connected to the key switch, it's connected to a circuit that's live whenever the key is in the run position. Some things to check while leaving your pin 1 live:

- glow relay shuts off/times out after 30-45 seconds. You'll hear the relay click and the dome light will get brighter

- I was going to say the relay should shut off with a momentary +12V through pin 2 but I don't know if that will happen with an afterglow relay.

I hope you're safe and dry!

Sixto
87 300D

Stay safe.

Thanks for the concern guys... we didn't get hit directly where I am, the devastation though in other parts of my country is apocalyptic. :( Feeling a little bit guilty that I can't do anything for them.

I followed the youtube demo... I just can't get the timer to function.
here's the link...
Mercedes 300D Glow Plug Relay Operation - YouTube

It's a different relay though...

http://www.autoprospect.ru/mercedes-...images/646.jpg

N14/2 - Glow plug relay
R9 - glow plugs
N3/8 - EVE control unit
M1 - starter

:)

Have to ask Dr.... where did you get that drawing ??

very nice just wish it had more descriptors for the callout connections

excellent