1979 300D I have just changed the speedometer to mph from kilo. After i got done the glow plug circuit stop working. The light does not come on and there is no voltage on the glow plugs. so after looking at the schematic and making a few measurements on the glow plugs. I wanted to find the relay, but have not found it yet. any help would be nice. thanks russ

some of the early 123s had it under the steering column. This will be the case if your fuse is on the firewall. Speaking of which, did you check the fuse? If its under the steering column then just drop the plastic panel and it will be a silver color rectangular box about 2 inches wide and 3 inches long with 6 pins I think.

If your fuse is not on the firewall than your relay will be on the left wheelwell towards the front. The fuse will be under a cover. The fuse is a strip of metal with a screw at each end.

Hope this helps.

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1959 Gravely LI, 1963 Gravely L8, 1973 Gravely C12
1982 380SL
1978 450 SEL 6.9 euro restoration at 63% and climbing
1987 300 D
2005 CDI European Delivery
2006 CDI Handed down to daughter
2007 GL CDI. Wifes

The relay IS under the drivers kick panel. Do check the fuse on the firewall. Think of what you might have disturbed while pulling the instrument cluster. Did you pull it from above, (which you should) or did you try to push it out from underneath?

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.