A friend of mine has the above mentioned car. He said that it is not starting and he is trying to find the glow plug relay among all of the other relays. How can he identify which one is for the glow plugs? Is their a numbe or even better yet a picture? Thank you so much.

Follow the wires from the glow plugs back to the relay.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Thanks, so I can assume the relay is under the hood then? This is not my car and I'm talking to a friend about it away from the car so it makes things a little more difficult.

On the drivers side inner fender.

Attached Thumbnails

 

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83 SD

84 CD

It's under the hood, on the front edge of the left wheel well, next to the oil cooler (the skinny radiator next to the real radiator).

It is all black plastic, about 2" wide x 4" long by 4" tall, with a snap-on cover. Remove the cover to test the fuse (the little aluminum strip); remove both phillips screws and hold it in your hand. Do not just visually inspect it and determine that it's good. The fuses are about $0.45 at places which carry MB parts.

http://www.buymbparts.biz/ShopByVehicle.epc?q=1983-Mercedes--benz-300sd-Body--Electrical&yearid=1983%40%401983&makeid=63%40%40Mercedes%2DBenz&modelid=6207%3AMBC%7C1510%3AED%7C10000134%40%40300SD&catid=241959%40%40Body+Electrical&subcatid=242005@@Preglow+Time+Relay&mode=PA

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James Marriott
2003 Buick Regal
1983 300D (228k, frau Auto)
1996 Suburban K2500 (192k, 6.5 turbo diesel/4WD towmaster 10,000)
www.engineeringworks.biz
1987 300SDL junker 170k
1982 300SD junker, 265k

See Diesel Giant for easy glow troubleshooting. The relay may be good but the plug bad. You only need a volt meter to diagnose.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Ohm meter also.

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83 SD

84 CD

Is that the entirety of the glow control system, or is the timer somewhere else?

Timer is part of the relay. Relay makes an audible click when it times out. Relay is energized from the ignition switch. Relay switches main power to the GPs. Main power comes from the battery to the terminal strip in the right fenderwell, then over to the GP relay contacts and on to the GPs. When the relay is energized, you should see 12V at the tips. Just a tiny bit of resistance in the path from the battery through the relay contacts to the glow plugs can affect GP operation. Engine ground strap can affect GP operation too, but that would probably also affect the starter.

Reason you pull the fuse out to inspect is that it can crack in the middle.

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mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)

Ok, just wanted to make sure I had everything before the car goes away.