1976 300D location of glow plug fuse and timer relay? - PeachParts Mercedes-Benz Forum

mercedes hawker · #1 03-28-2006, 06:57 PM

Hello does any one out there have a quick description of where the glow plug fuse would be located on a 1976 300d? The glow plug timer relay?, It is not the newer style that is on the fender with the plug connections
Thanks
mercedes hawker

#2 03-28-2006, 07:22 PM

It does not have one unless some one upgraded the type of glow plugs. If you have, a solid, un-insulated wire shaped like a W running from glow plug to glow plug. The pull start (gorilla knob) turns the plugs on and off you look at the salt shaker a little round thingy to the left of the steering wheel until it glows red then pull the start handle all the way out to crank the engine. The disadvantage of these older glow plugs is if one plug dies they all fail to work and the salt shaker on the dash that glows red when the plugs are hot is actually a glow plug in there glowing red if it burns out you are really screwed. What is it you are trying to do?
Dave S

mercedes hawker · #3 03-28-2006, 07:32 PM

hello thanks for your reply. This 300D has a key start and stop. NO knobs to pull. Turn the key on and let it sit a second ( only light is the red alternator light) then try and start ( cold nothing , a little tiny shot of starter fluid and it starts up fine and idles fine. Turn it off and it starts back up. just not cold starting. I have a haynes manual but the closest Wiring diagram I can find is a 1977 300d and it show a 50 amp fuse in line with the glowplugs down line from the timer relay.
any more help is appreciated
thanks
mercedes hawker

#4 03-28-2006, 07:48 PM

Sorry then that is how my 1976 W115 is and I thought all were that way a lot of people have converted there’s to the newer style glow plugs eliminating the long wait for warm up and eliminating the gorilla knob completely. There is a thread some one just started asking a similar question mix 'n match glowplug relay...?
In it some one states Mercedes used the old glow plugs like I described until 1981 so maybe some one has upgraded your car to the pencil style plugs using that as a search word may come up with something helpful.
Dave S

300SDog · #5 03-28-2006, 08:07 PM

Is this 300D a w123? If so its got the old loop style plugs and the fuse is a strip of metal in rubber box on the firewall where the GP wire comes from. You can fake this fuse using a cut up aluminum can. Dealership sells the fuse for about $1.89. The relay will be a larger rubber box on the driver's side fender well. And if loop plugs burn out its really obvious, the loops will be severed like burnt out light bulb filaments.

mercedes hawker · #6 03-28-2006, 08:13 PM

I am going to call this a 115 as that is what the vin # starts with. I think it has the old style glow plugs . I can not find the timer relay anywhere on the drivers fender. The main glow plug wire comes out of the wire bundle near the firewall. I am guessing it goes from rear to front. At the last glow plug near the radiator end the wire doubles back and goes to some sort of temperature sensor? Does that make sense?
thanks
merc hawker

mercedes hawker · #7 03-28-2006, 08:18 PM

Still looking for the glow plug fuse and relay on the 1976 300D,. The whole search started with a cold start problem, then I found no voltage on any of the glow plugs as described in the haynes manual.
any help would be appreciated
mercedes hawker

hawthorne90250 · #8 03-28-2006, 08:48 PM

The relay for my 79 is inside the car near the steering wheelshaft,just remove the foot panel and i can see it, i cannot say for certain where yours is, but have a look there.

mercedes hawker · #9 03-28-2006, 09:13 PM

Thanks for the reply I will check in the morning. Any body else have the location for a 1976 300d glow plug fuse and relay

doppx006 · #10 03-28-2006, 10:10 PM

I will look tomorrow on my 1976 300D 115, but for mattdave was your 76 115 a 300D? Because I thought I remember reading in the owners manual that the 240D had the old style pull knob, but the 300D had the key. I believe all 300D 115's had the key, well good luck i will look tomorrow.

#11 03-28-2006, 10:41 PM

Your right mine is a W115 1976 240D
Dave S

mercedes hawker · #12 03-28-2006, 11:21 PM

I checked the firewall, and the fender no joy. I will have to wait until day light to check the footwell I am guessing you all are talking about next to the steering column, above your knees if you were sitting in the drivers seat. The wire that feeds the glow plugs disappears into the main wireing harness. I would hate to have to cut that open. It seems some one will know where it is .
thanks for your continued help still looking
mercedes hawker

joshhol · #13 03-29-2006, 06:54 AM

Hey, preglow timer relay is a silver box underneath the dashboard right by the steering wheel. Unscrew the cardboard vanity panel and look on the left of the steering column. I don't have a picture but maybe you can see a picture on fastlane. It's silver with a flange attached with screw holes. I never did figure out how to attach it but it just hangs up there when you re attach the cardboard. My glow plugs wouldn't shut off when it went bad.

Cheap part, easy fix!

joshhol · #14 03-29-2006, 11:44 AM

By the way, please tell me you're not using starting fluid anymore!!!!!!!!!!!
Unless you are trying to kill your car.

mercedes hawker · #15 03-29-2006, 11:51 AM

Thanks for your reply's,. There are quite a few relays and such up under the dash. There is one that looks as you describe almost mounted on the left side of the steering column. THere is also another a little to the left it is much bigger and is mounted on some sort of bracked I guess. I am trying a picture. It is the one on the rights side of the pic correct? The auto zone price is like $130, is that correct?
thanks for your continued help
mercedes hawker