location of glow plug relay on 79 300D? - PeachParts Mercedes-Benz Forum

jblueep · #1 12-21-2006, 02:05 PM

I found several threads on this, but I could not find anyone that said exactly where it is, and I could not find any thread with a picture.

This is not the style where it is on top of the driver side fender well. From what I have read, it is in the dash somewhere, but I can not find it.

Many have said it is on or near the brade pedal bracket, but the only relay there that I can find is the cruise control relay.

Can anyone help or send pictures or tell me how to find it?

Thanks

vstech · #2 12-21-2006, 02:23 PM

if it's not been answered by the time I get home, I will post a pic of mine... don't forget it will only have one wire leaving it, due to the serial nature of the GP's on this vintage vehicle.
I belive it is on the steering column below the dash cluster.
John

jblueep · #3 12-21-2006, 02:52 PM

A picture would be awesome.

The wire that goes from the relay to the fuse on the firewall in the engine compartment is missing (I just bought the car), so I don't have a wire to follow back from the fuse to the relay.

I'm wondering if the relay was also removed (before I got the car) and that's why I can't find it. But I can't find any loose wires under the dash where the relay should connect

vstech · #4 12-21-2006, 03:29 PM

Quote:

Originally Posted by jblueep

A picture would be awesome.

The wire that goes from the relay to the fuse on the firewall in the engine compartment is missing (I just bought the car), so I don't have a wire to follow back from the fuse to the relay.

I'm wondering if the relay was also removed (before I got the car) and that's why I can't find it. But I can't find any loose wires under the dash where the relay should connect

WHY???

arrgh, aint it crazy what PO's do? I bet the OEM relay was upgraded to the modern paralel type and the seller kept the stuff for another car when they sold the car.
I have a parts car with wire and relay if you don't have yours just let me know.
I'll try to get you a pic tonight.
John

jblueep · #5 12-21-2006, 03:52 PM

The plugs were still wired in series (not parallel), so I don't think the previous owner upgraded the glow system. All the plugs were burned out, so I think the relay went bad, the guy pulled it out, but was too cheap to put in a new one. He was starting it with starter fluid.

Fortunately, he doesn't seem to have done any damage with the starting fluid, at least that I can tell. It runs great, and only has 94K original miles. I've started it a few times with mostly WD-40 and and little starting fluid and driven it several hundred miles.

There is one slightly burnt wire (large red hot one off the light switch). I'm wondering if that powered the relay.

I bought another relay (I think I overpaid at $175), so I might send that one back, and wire in a ford starter solenoid and a push button switch (at least temporarily) since I don't know if there is a wiring problem. I don't want to start it with starting fluid at all, so that may be a stop gap solution until I figure out the relay situation.

Thanks for any pics or help you can give, and I might take you up on that relay and wire

jblueep · #6 12-22-2006, 11:25 AM

Anyone have a picture for me? Please

rrgrassi · #7 12-22-2006, 11:44 AM

For the $175 you paid, you could have bought the upgraded parallel relay and glow plugs from Phil, (Fastlane) the reason this forum is available.

I do not have any pic's and my car is an '82.

jblueep · #8 12-23-2006, 05:41 PM

Well, for now I did a nice little $20 fix with a ford starter solenoid and push button switch. Worked like a charm, and I can completely (albeit manually) control the glow cycle.

I still would like to know where the relay is so I can fix it "right".

Stevo · #9 12-23-2006, 07:19 PM

Quote:

Originally Posted by jblueep

Well, for now I did a nice little $20 fix with a ford starter solenoid and push button switch. Worked like a charm, and I can completely (albeit manually) control the glow cycle.

I still would like to know where the relay is so I can fix it "right".

Using the "push button system" you can easly switch to the new style GPs just go to a 80 amp strip fuse. I have the push button system in my "79" and when the relay craps out in my "85" it will become a manual system also.

carusle · #10 12-23-2006, 08:01 PM

try this http://dieselgiant.com/mercedesdieselloopglowplugrepair.htm

jblueep · #11 12-24-2006, 11:25 AM

I had already purchased the old style plugs, so I stayed with those for now. If I need to replace them in the future, I'll switch to the new style.

I'm just glad to be off the starter fluid!