'83 Mercedes 300CD

[DaveMcDonald]

Hello, Need some insight into a glow plug(s) debacle. My wifes '83 300CD would not start this morning. ( I was not home) Out of frustration she kept trying to start it and it finally fired up. My first suspicion was the relay strip fuse. It was OK. Second, I swapped out the relay. Still no light coming on for glow plugs. Third, I happen to have a excellent turbo deisel on an engine stand, so I changed all the glow plugs from one engine to the other ( just to see if in fact I had a glow plug problem.) Made no difference. Is there another fuse or perhaps I'm overlooking something?? The glow plugs are getting power, confirmed with my test light., but the glow plug light does not come on. ( No its not the bulb, it starts very hard- no glow plug heating.) Any help would be appreciated. Thanks! Dave