Parasitic drain issue.

Starter ruined due to high voltage. I wonder if 24 volt machine which can be charged from truck engine 12 volt has something to do with this? I will checking that link.

 

positive wire touching the frame, etc..

 

If you disabled everything and it's all going wonky I'd check the main starter cable from the batteries. It's probably rubbing on the frame above the batteries.

 

OK because there is something mounted on the back end of the truck, try disconnecting that from the rest of the truck.

The flashing of lights and so on may be the body computer freaking out, this truck is something else with all the modules.

I don't see why you would get 7.8 volts, you need an amp meter - the power probe is good but they need to add a 100amp meter feature to it.

Also so you understand the complexity of this mess - the M2 - here are a couple links to electrical info for the M2. These explain a little about the modules and what wiring, fuses and so on are on the truck.

This is about the 2007 M2

https://secure.freightliner.com/acc...07 Electrical Body Builder Manual Rev New.pdf

This is about the 2010 M2 - it still helps if the chassis was uprated

https://secure.freightliner.com/acc...0ElectricalModels-M2106-M2112-108SD-114SD.pdf

 

Ridgeline you are the person!!! I got more info from that link than anything from freightliner. Thanx a million.

 

All the grounds were coated green. Pulled starter to get tested and it was inoperable due to high voltage and corrosion everywhere. Bought a big tub of bulb grease drilled holes in bottom of all turnsignals to drain water from rain out.

 

Changed starter and now it won't crank is there a way I could have miswired? There is only 2 posts 1 little and one big which has an adapter on it for the other 2 wires that are big. Will be checking for voltage to starter next. Read something about a fusebox in the VIM what is that and where is it?

 

bought cheap tester at menards thinking it would measure amps, but could only get ohms. 150 ohms on a 12 volt circuit= 14 amps. Also got exact same reading when i went directly to battery itself. Hope this helps.