1980 300CD glow plug timer troubles

My glow plug timer seems to have stopped working on my 1980 300CD. The dash light flashes but will not stay on with the ignition switch at position 2. I
went through the diagnosis section in the mercedes engine manual and everything checked out. I replaced the glow plug timer and the new one acts the same as the old one. There is still no current going the glow plugs.
I've checked the resistance of all the glow plugs along with the lines to the plugs. I've also checked the resistance of the lines to the temperature sensors? I believe there are two in the head. The sensors seem fine. Now I'm really annoyed, plus I have a $174 part which I hope is not defective. The glow plug timer on my 1980 300CD was used for exactly one model year.
Any suggestions are most welcome.
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What a coincidence, I am having the exact same problem, if you find the problem please let us all know!

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Basic question: Have you replaced the 80 amp fusible link?
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Good question, I'm not sure.
If you mean the metal fuse under the relay cover, yes it looks OK. If there is a wire that is a fusable link, I did not know of it. Is there a fusable link wire?
I am thinking my problem might be the switch because the light does not go on sometimes and if I turn the key more forcefully the light goes on for about two seconds.

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That's too basic of a question. I tested the resistance of the 80 amp fusible link on my old glow plug timer and it was 0.1 ohm. The new timer in the car right now came with a new 80 amp fusible link. It's pretty unlikely that it's the fusible link.
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If fusible link is OK I'd check the ignition switch.
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OK but why? I have switched current going to the glow plug timer at terminal #2. You really think it's the ignition switch?
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Check out this site.
http://skinnerbox.steaky.org/123_DISK2/program/123-cd-index.html
It has info on the System. 15 - Electrical system engine (ignition system, preheating system, starter, alternator) That should/might give you some help...
Bill
Writes:

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Bill: Thanks for the link to the factory manual. Actually, I already had it bookmarked and I also have the factory book. I've been through the factory diagnosis and it seems that I may have a new defective glow plug timer.
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