where is the glow plug relay on my 1980 300D?

Errmm.......I think it is on the front drivers side fender just aft of the headlamp assembly...Black box with cover....80amp fuse underneath ?

Enquiring minds wanna know !

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The last post is probably right. Relay was originally located above drivers footwell in dash around the top of brake pedal. The only reason I mention this is I was not sure of year they moved it to the engine compartment. Was above the drivers footwell in 1977 for sure. I think a way to find it easily is to find and follow the lead from the glow plugs. It will go to a strip fuse holder. From the other side of the strip fuse it will go to the relay I believe. Just not personally familiar with your year.

My '80 wagon had the GP relay on drivers side inner fender behind headlight, as mentioned above.

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Uhmm, in my post above I mentioned my 80 wagon, and how the relay was on inner driver fender. Non-turbo...
It may have to do with the pencil style plugs vs the older style.

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

It's also on the inner fender on my (non-turbo) 83 240D.

in my 79 non turbo it is underneath the dash...

I'm sure you'll find it!

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'87 300SDL, intensely modified Greasecar setup, with nickle plated heat exchanger, 3 valve setup, 312,000 miles
'95 Suburban diesel, Greasecar basics, 16 plate heat exchanger, mercedes fuel lines, Racor filter
'85 Renault Alliance converted full electric vehicle

This would help support the "old style" vs "new style" glow plug relay location. (or I guess it could just be a "year" thing)
And voice, no worries. I'm guessing out my backside as it is........

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

I am not going on ebay to buy a 1980 123 diesel to find out. Would not help anyways as relay would probably not work. So the one way you can find it for sure. When relay has finished its function it clicks off. If your hearing is normal you should be able to detect it's location by sound. If all else fails ask the wife.

If you have the pencil style plugs then its on the inner fender. If you have the loop style plugs then its under the dash.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
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I love the smell of diesel smoke in my hair

Glad in a combined effort we can nail down these large issues. Squiggly bare wires between the glow plugs should put the relay inside the car. Just normal wires to the glow plugs should identify its location to under the hood. Either way at this point function is more important than location perhaps. That is unless you have found out already it is not functioning. You might just be in the final transition year as well. Also quite a few of the series plug cars were converted to the newer function plugs and the original relay was left functional up on that pedal assembley with the conversion. Think all possible variations have now been covered. Tell us you found the relay yesterday.