I have been having some cold start problems with my 1984 190D 2.2. The car I beleive had bad glow plugs so I replaced them. I have just finished the install and went to start the car. The glow plug light did not ocme on and the car wont start. The light worked before I installed the new ones. I need to troubleshoot this problem, and am wondering where to start. I do not think that damaged any of the wires installing the glow plugs. What does the glow plug relay look like and where do I go to check the resistance in the circuit???
Thanks in advance
Evan

The glow plug relay is a little black box located in the engine compartment on the front inside face of the drivers side wheel housing. The top cover comes off of the relay, and you can see a metal strip fuse - check that this is intact. Also confirm that you are getting +12V at the relay.

You can unplug the large plug; this contains the wires that run to the four glow plugs. Use a multimeter in resistance-measurement mode to test the resistance of each plug separately via the sockets on the cable (not the terminals on the relay). To do this, solidly ground one lead of the multimeter on the engine block near the glow plugs, and then stick the other lead of the multimeter into each of the plug sockets (only 4 of the sockets will be used on your car since there are 4 glow plugs). You should see something really low but non-zero (around 1 ohm if I remember correctly) if they're connected properly.

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1989 250TD Wagon 5-speed, 160,000mi ::: Dark gray metallic / black cloth
1984 190D-2.2 5-speed, 287,000mi ::: Silver-blue metallic / black MB-tex ::: SOLD

ok...thanks for the help. I found the problem, I have blown the fuse that is under that cover. Does anyone know what that fuse is....like amperage and the type? or is it mercedes specific? if mercedes specific, any idea of the part #?

Thanks
Evan

Part # P2015-84449 it costs $0.69 and it's listed as strip fuse in the Fastlane parts here on this site. If you want to check it out yourself, go to the Buy Parts tab at the top of the screen, give your model year, make and model, then look under Body Electrical.

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TXBill



Former owner of a few diesel MB cars
1998 Lexus ES 300 In Chicago We Trust

If the fuse is blown, that's usually a sign that there was/is a short circuit somewhere... Unless you fix that problem, it's possible that the new fuse will blow too. Check that none of the glow plug wires are shorted out against the engine before replacing the fuse. To do this, check the resistance on each glow plug wire by measuring them through the connector at the glow plug relay (as described earlier) and ensure that you don't get any zero-ohm measurements.

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1989 250TD Wagon 5-speed, 160,000mi ::: Dark gray metallic / black cloth
1984 190D-2.2 5-speed, 287,000mi ::: Silver-blue metallic / black MB-tex ::: SOLD

well im having more problems now. I checked the resistances on all the glow plugs and they are all close to but not equal to zero.. I believe that one of my glow plug wires shorted on the engine block, I have dealt with that. My next problem is.....I tried to bridge the broken fuse with a strip from a 24A fuse I had lying around and stil could not get the glow plug light to light up. I can hear a tick from under the hood when I turn the key to where the glow plugs should be used after a little bit. Where else should I start checking for problems?

If you want, you can send me a private message with your e-mail address and I can forward you a detailed troubleshooting PDF file from the service manual.

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1989 250TD Wagon 5-speed, 160,000mi ::: Dark gray metallic / black cloth
1984 190D-2.2 5-speed, 287,000mi ::: Silver-blue metallic / black MB-tex ::: SOLD