Another glow plug issue

[Screamer27]

Yes I searched, for over 2 hours now reading post after post and found some very valuable info. I have done some diagnosing, and still coming up blank.

Over the last month the m1009 has been getting ALOT harder to start. Finally yesterday, It spins over fine, but just won't hit. If I go from the tip of each glow plug to ground, I have OL on the meter, meaning all of the glow plugs are dead. If I go to the wire terminals going to the plugs, and key on I get 24 volts for about a second, then I have 1 volt for 3 seconds, the relay keeps cycling about 3 times while the wait light is on, yet keeps cycling with the key on, but the wait light out indefinitely. If I jump the blue wire to ground from the relay, I have constant 24v at each glow plug. I relize all of the glow plugs are bad, but I want to fix any other issues before I blow 100 bucks on glow plugs, and have them all blow instantly. The wait light seems to be working fine,

 

[doghead]

All it takes with the original system, is for one GP to go bad, the rest will follow immediately. If you notice harder than normal starting, then you need to diagnose your GPs immediately

You should be able to find GPs for less than $100.

 

[Screamer27]

I understand that, but I want to make sure nothing else is wrong before I throw glow plugs in it and they all burnout again. I know something is up when I have 24v for a second, then 1volt for 3 seconds, 24v for another second, then 1 volt for 3 seconds, then the wait light goes out. I still have 24v for another second, then 1 volt for 3 seconds, and this will go on for 15 minutes or more, how ever long the key is on. In theory shouldn't I have 12v or 24v until the wait light goes out?

 

[doghead]

Yes, but the voltage cannot be measured/tested or expected to drop, unless you have 8 good GPs in it.

Also, there can be voltage applied to the GPs without the wait light on.