M1009 Electical Bizarro Problem - Need Guidance and help...!

[Asmoday]

M1009 Electrical Bizarro Problem - Need Guidance and help...!

Hello all,

I haven't posted in a while but I have been lurking a bit... I now have a major issue with my M1009.

This AM I went out to start her up...waited for the "wait" light to go out...turned the key...got a quick starter engage and that was it....everything went dim. I turned off the ignition and back on again and now have the repeatable scenario in the video that follows.

When I first turn on the ignition the Volt Gauge reads nothing but eventually begins to show activity. The appropriate instrument lights glow very dim.

Play close attention how the system eventually seems to return to normal but once I turn the key to try and start it...it starts it's weirdness all over again.

The video is worth a thousand explanations...

View attachment Cucv-1.mov

The batteries tested out fine but I went ahead and put a new fully charged battery in the rear and the scenario is the same. The driver side alternator was replaced new about 4 months ago.

All the 12v and 24v voltages measure correctly with a Fluke meter at the normal points but once I turn the ignition on and the glow plug relay starts chattering the voltage drops to between 4.5 - 5 volts.

It has the Doghead starter relay mod as well as the glow plug relay mod. The electrical system has been near perfect until now....

I'm definitely going to need some help and guidance on this one...!

Thank you,
Adam

 

[GunnyM1009]

Mine did this once it turned out to be bad grounds and bad connection at the terminals

 

[tim292stro]

How did you test the batteries? Volt meter only or load tester? The front battery is the 0-12V battery and is the one which powers everything (except the glow plugs plugs and starter if 100% original wiring - GP relay and controller are still powered from 12V). Changing a rear battery only is not going to have much effect on your 12V symptoms.

Make sure you clean any electrical contact you touch - it's funny how many volts you can lose with dirty or partially corroded battery terminals...

 

[dougco1]

How did you test the batteries? Volt meter only or load tester? The front battery is the 0-12V battery and is the one which powers everything (except the glow plugs plugs and starter if 100% original wiring - GP relay and controller are still powered from 12V). Changing a rear battery only is not going to have much effect on your 12V symptoms.
Make sure you clean any electrical contact you touch - it's funny how many volts you can lose with dirty or partially corroded battery terminals...

I agree with Tim, mine had the same symptoms as yours. I checked the voltage on both batteries and they read good. So thinking the batteries were good I went on a gremlin hunt for the next 3 hrs. Was ready to bite the bullet and drop the starter but decided to Load test both batteries first. The front one had a bad cell. They were both 7 years old so I replaced them both. All is fine now.

 

[Asmoday]

Thanks all for the suggestions.

Both batteries were load tested and fine (they're also less than 3 years old... Interstate 6TL models). All contacts, battery terminals etc. are shiny clean and clamps are tight etc. All the basic stuff has been checked. There are no loose connections that I can find.

The glow plug resistor has been removed and the 12v glow plug relay was installed a couple years ago along with the appropriate glow plugs.

The vehicle has been a daily driver for the last few years. Realize it literally was like flipping the juju switch and the problem was there...

 

[royalflush55]

I would suspect the fusible link that feeds the ignition switch or the ignition switch itself. I am not talking about the keyed cylinder but the electrical contact ignition switch mounted underneath on the column. The wire that feeds this switch is located on the 12 volt diamond on the front of the firewall by the glow plug relay. Pull on the fusible links good to check for one partially burned into. Good luck!

 

[eme411]

sounds like batteries to me , I have had the same thing , replaced both batteries and never looked back, the 6TL like to short out inside , anybody close to you that can slave your truck?

 

[MarcusOReallyus]

I would suspect the fusible link that feeds the ignition switch or the ignition switch itself. I am not talking about the keyed cylinder but the electrical contact ignition switch mounted underneath on the column. The wire that feeds this switch is located on the 12 volt diamond on the front of the firewall by the glow plug relay. Pull on the fusible links good to check for one partially burned into. Good luck!

What he said.

 

[Rustyshackelford]

I agree it sounds like bad batteries or a bad connection. I don't mean to be condescending but you know what "load" testing means right? It is super imperative that the batteries are load tested and not just tested with the multi-meter. I had a 9 month old interstate battery that showed 12.8V but load tested as a bad battery. I spent an extra day chasing gremlins just because I was lazy about load testing.

 

[tim292stro]

I would suspect the fusible link that feeds the ignition switch or the ignition switch itself...

What he said.

Ditto

 

[antennaclimber]

http://www.steelsoldiers.com/showthread.php?72880-Battery-Wiring-Maintenance&highlight=

Some other things to check are mentioned in this thread.

I suspect you have a bad battery, connection, wire or other issue with the front battery.
The GP relay chattering means that it is not getting a solid dependable 12 volts to it.

Can you put a voltmeter directly on the front battery terminals and see what the voltage is while cranking the engine?