Hey everyone i want to start off by saying i'am a newb and i need some diagnostic help.

The problem is my glow plugs aren't working on my 79 300D.
I replaced the fuse in the relay box but nothing...So i re wired the Glow Plugs hopeing the first plug was shot, but still nothing.

Is there anything else that could be causing them not to be working Other than the Relay?


Also i'am unsure if this is related so i'll mention it anyways.
I noticed a humming noise coming fron a black box on the passenger side fenderwell when i turn the car on. *I beleive it is the KLIMA box.*
The KLIMA has been replaced fairly recently, but before i purchased the car.
I figured i should mention it just incase i'am mistaken and it is not a KLIMA box and it has something to do with the plugs.

Thanking you in advance,
Jay.

Are they the original loop types? If one of those go bad non of them will work. There is also a fuse on the fire wall, it looks like a small metal plate. follow the wire from the plug closest to the fire wall up to the fire wall, the fuse is there underneath a plastic cover.

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Sonny


86 190D N/A 2.5L Auto 265k "Ruby" -Sold-
79 300D 242k "Condi" my first -sold- RIP
2013 chevy sonic hatchback - had to for work

They are the Old loop style plugs, but i rewired them so if one burns out the others will still work.
And
Yes i replaced that fuse also.

Thanks for your reply.

Anyone else?

'Splain how you did this.....

__________________
Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

When you rewired did you change over to the pin style glow plugs.

my set up with pin type glow plugs has a fuse in the glow plug relay(BLACK BOX)
box. Check that.

Check these diy's they might help

http://dieselgiant.com/mercedesvoltageregulatorinstall.htm
http://dieselgiant.com/glowplugrepair.htm
http://dieselgiant.com/mercedesdieselloopglowplugrepair.htm

Nandopsis, Wiring all the loop style plugs is not recommended! Picture what happens when you wire all your miniature christmas tree lights in parrallel. Series wiring is protecting your glowplugs from overvoltage. You have burned out your glow plugs so you might as well replace them with the pencil type because those are meant to work in parrallel. (independently) you loop plugs are like those tree lights, they only take 3.5 to 4 volts each, but if you wire them together one after the other, you can wire up enough of them to plug your light string into 120 volts household current. But, if you wire them independently, you will be putting 120 volts into a 4 volt bulb and it will burn out immediately, understand? I believe this is what you did to your glow plugs! Now get the solid pencil type and wire those in parrellel, their meant for it and they are much more dependable anyway. I'm not sure about your relay, if the one you have will work with the pencil type glow plugs because those will have a higher current draw than the series loop type, but that relay will not be hard to find and if I remember correctly, it will plug directly into your socket where your old one came out. let us know what happens! If anyone has more info on the relay, correct me as I'm a bit foggy in that area. It's been awhile

I am thinking that this may be your problem...
John
oh, and kilma came out in 85 I believe, and it controls the A/C compressor.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

The feeder wires between the plugs are a resistor in themselves or at least the squiggly ones are. Thats why they heat up when the glowplugs are on. Any attempt to change the wiring is going to either burn out some if not all the plugs. Or result in all voltage seeing open circuits.
The only way the plugs may still be good is if you thought they were grounded to the block internally and only fed one wire to each plug. Then you would tend to have multiple open circuits. Post exactley what you have done. The situation may still be salvagable with a little luck.
I think the plugs are only raterd for about 1.3 volts individually. This must be applied between the two points on each plug. Between either point on each plug and the ground of the block no harm is done other than they will not work. The plugs are rated only for about a volt and a half individually. This voltage and description of course only applies to the large loop plugs for series operation.
Also my 79 240d still has the glow plug relay under the dash. There is a black box on the drivers inner fender though. It seems to contain three ice cube relays. These have nothing to do with the glow plug function at all I believe. You are right though whatever it is should not be buzzing. You are not hearing a door open buzzer are you? I do not even know if you have one.