Glow Plug Indicator Light Out
 

I have a 1983 300D, glow plug indicator light not lighting upon turn of key. Does this indicate a glow plug out or is it just a fuse or bulb??

First check the bulb. If the bulb is OK, it is either a defective relay or the relay is telling yopu that you have one or more glow plugs out. Check the glow plugs with an ohmmeter. Each should measure less than one (1) ohm. Replace bad glow plugs as necessary. If the glow plugs are all good, then the relay may have failed.

Are you having problems starting the car?

On mine, it was an indication of a failed gp, I tested with an ohm meter, and found the bad one.

How do I go about checking the bulb? I really am having no trouble starting it, plug it in when it is too cold out and it starts as good as can be expected for wintertime

Also, is there anyone nearby in Ct area that can help me that has an ohmeter and would be willing to check the glow plugs for me?

Pull the instrument cluster, lots of threads here describe how. Then pull the lower-right-most bulb (in a socket with a wire pair coming out) and remove the bulb. Test with an ohmmeter or replace with a known good bulb.

Remove the smaller connector on top of the relay box. Jump battery voltage (the large wire to the relay box is always hot) to terminal #3 (blue/white wire) on the connector. The lamp should illuminate.

Bulb would be the last thing I'd check. Ohm meter on the glow plugs would be first. Not only is it a whole lot more likely that it's a glow plug problem, but it's also a whole lot easier to check.

i accidentally discovered when troubleshooting glowplugs last time in my 85td when the light quit coming on, that if i left the connector to the plugs from the gp relay unplugged and then turned the key to glow, that the dash light would come on and go off real quick. Dont know why its like that, but may be an easier way to test the bulb than pulling the cluster

Can you check the plug resistance with a paper clip?