PeachParts Mercedes-Benz Forum - View Single Post

JimSmith · #9 12-14-2004, 07:28 PM

85drtysthbenz,

First, you need to confirm you have the right connector. The black box on the driver's side fender, forward side, has a couple of wire ways entering it. The one that comes from the engine (it should be visibly traceable to the glow plugs) has five connections in it, and one blank spot, with an orientation pin so you can only get it on one way. If you look at the underside of the connector after you get it off, it should have "1, 2, 3, 4, 5" labels for each cylinder's glow plug kind of cast into the plastic. Once you confirm that is the plug you have, you put the red lead from the multimeter to the electrical connector (a sleeve) in the plug, and the black lead to the valve cover or some other covenient grounded surface. The multimeter should be set to the lowest scale you can pick over 1 Ohm as the reading should be around 0.9 Ohms.

Go from connector pin to connector pin. Make sure you get a good contact between the sleeve and the red multimeter lead probe, and on the black, ground probe.

Write down the values. If they are less than the 0.9 Ohm value, report back. If they are barely more than that, report back. If there is a dead short (zero Ohms) or a break, or a few or more Ohms, the plug is bad. Like Larry said, if one is bad, you might as well replace them all, and keep the ones you think are good as emergency spares. I found the new ratcheting box end wrenches from Sears worked wonders for removing and replacing glow plugs as I just did one on my 1982 240D. No cut up hands and I got around the fuel delivery tubing. Good luck, Jim