I forgot to ask if despite the Glow Plug Light issue if your Engine is starting OK?
You have been a member a long time. If you have read any of the threads or posts on this I believe the first thing folks would say to check as the Glow Plugs themselvers as the first plasce to start.
You can go to the Diesel Giant Site and follow his pictorial with the Ohm/Volt Meter (multimeter) or you can go to the DIY section and see if we have a proceedure. His pictorial I believe is for a 123 but the method is the same.
The good thing here is you can check the Glow Plugs without removing the Intake Manifold.
If it turns out any of them are no good I would read up on removing them before I tried to do that as the long Glow Plugs in the Aluminum Heads sometimes break off in the Head when you try to remove them.
DIY Repair Links
http://www.peachparts.com/shopforum/diy-links-parts-category/
http://www.peachparts.com/Wikka/DoItYourSelf
If the Glow Plugs appear to be OK and your system has a ExternalTemp Sensor connected to your Glow Plug Relay I would suspect that.