300D glow plug problem
 

The glow plugs have stopped working on my 85 300D. Symptoms are no indicator light and extremely hard starting. I have found the relay but I am not sure where to find the fuse. I looked in the panel on the firewall. Is there a fuse and/or a fuseable link somewhere? Is there a way to test the relay?

Pull the plastic cover off the top of the relay and you will see a bar fuse between two screw terminals. This fuse will often crack from vibration and you will not easily see the crack.

Use a voltmeter on one of the glow plugs referenced to ground and have someone turn on the ignition. If you don't see voltage at the plug, then work back to the relay and fuse. If there IS voltage at the plug, replace all the glow plugs.

Good luck,