Friends,
Thanks in advance for any advice you might have! I've recently replaced the old series style glow plugs in my 76 300d with converted pencil style relay plugs and wiring.

I purchased a voltage meter today to see if they were working. To my dismay, there was no reading when the ignition in the "2" position. However, after some playing around (and dumb luck), I learned that the glow plugs do indead kick on in the "2" position AFTER a crank attempt. They each get a very nice, even 11.5 volts. They do this consistently, and shut off after about 30 seconds of the engine running. So, there doesn't appear to be any issue. Perhaps the relay just needs a jolt?

Has anyone else ever experienced this?