M1009 lost all electrical power

[deercoker]

I still think it was a bad battery.

My M1009 acted the same way as your ride and had me buffaloed for days. I went through all the motions of checking everything electrical. I even disconnected and cleaned all the grounds and fuse holders with no joy.
The battery and its connections was the first thing and then again last thing I checked. The clue finally came to me when the battery wouldn't charge above 12 volts nor hold the charge overnight. The next day it would read 10 volts.
I brought it to NAPA, their load tester said FUBAR when my el-cheepo home tester said it was good.
Hooked up the new "group 31 truck battery" they sold me and problem solved.

IMHO,
These CUCVs were well engineered back in their day but all their components must be "working together" as designed. If one part of the system is broken, bypassed, missing, or modified, it most likely will show up as a bigger issue down the line.

Not really sure but my loadtester has always proven to be working correctly, I will add also in my original post I forget to add that the voltmeter gauge worked up until the day truck died and didn't give it much thought because I have had the issue before even though both alternators were working properly in a previous cucv, after the relay change and new battery the voltmeter gauge is working again.

 

[deercoker]

Not really sure but my loadtester has always proven to be working correctly, I will add also in my original post I forget to add that the voltmeter gauge worked up until the day truck died and didn't give it much thought because I have had the issue before even though both alternators were working properly in a previous cucv, after the relay change and new battery the voltmeter gauge is working again.

I meant to say it worked up until the day I drove it and the died but that day it was not working

 

[Guyfang]

Don't think it was according to my load tester, however I changed it out because it was smaller than the back so they were miss matched and the bracket was not sitting on it correctly, I will use it on my boat though, still puzzled how the glow plug relay could shut off the power to the ignition switch and engine


Try this, if you still have the bad relay. Take a Multi meter and switch to ohms. Read from first one big terminal to the relay housing/case. Then the other. If you had a direct short to ground, that might just give you the symptoms you saw. Inside the relay could have been shorted to the case, and you would not see the damage.

 

[deercoker]

Don't think it was according to my load tester, however I changed it out because it was smaller than the back so they were miss matched and the bracket was not sitting on it correctly, I will use it on my boat though, still puzzled how the glow plug relay could shut off the power to the ignition switch and engine


Try this, if you still have the bad relay. Take a Multi meter and switch to ohms. Read from first one big terminal to the relay housing/case. Then the other. If you had a direct short to ground, that might just give you the symptoms you saw. Inside the relay could have been shorted to the case, and you would not see the damage.

Thanks