M923A2 electrical problems

[spcwohl]

Howdy everyone I've had my 923A2 for over a yr now and have out over 3000 miles on it and I was driving it one day it was a bit chilly out so bad the heater goin on the high side and as soon as I shut the ignition off I lost all 24 volt power to my ignition and all my other systems however I still had power to my lights and the low speed of my heater which if I'm not mistaken low is 12 volt and high is 24 but anyway I had not power to anything else when I turn the battery switch on and off I could hear the relay but when I turned the ignition switch on there still wasn't any power to the starter any of my warning lights abs etc. I kept trying to get it goin several times then I opened up the batter box and unhooked everything and hooked it back up and still nothing so I bounced the positive wire off the battery a few times and finally got everything to kick back on so I fired up the truck and my voltmeter was way in the red on the high side so could this be a generator problem protection Box or battery problem? When it turns over it sounds strong but if I let it runs to long I loose all my 24 volt power as soon as I turn the ignition off

 

[crolfe1984]

I want others chime in with a more experienced opinion, but my first thought goes right to the PCB (protective control box). Giving it a good whack or two when you don't get 24v on ignition usually gets things going again. This of course is a sign you'll need a new or rebuilt PCB. I recall a member on here selling them rebuilt for $150.

 

[Swamp Donkey]

I agree with failing or bad PCB. Multiple electrical issues popping up at once are usually caused by a failing or bad PCB. The 24V side of the blower motor runs through the PCB while the 12V side does not. Charging issues are also a symptom. If the batteries run down from lack of charging, your ABS light might come on since that system has a minimum voltage it wants to see. Another symptom is the gauges failing to respond when the power switch is turned on.

Most of the time cycling the power switch multiple times or tapping on the PCB will get you going. As you can see, you're on borrowed time though.

Now that you have a direction to take, search for some of the PCB threads. I think you'll find even more confirming information along with your options for rebuilding or replacement.

 

[spcwohl]

Thank you guys I appriciate the reply's. I too am leaning strongly towards the PCB cause gen tests out good, batteries test good on both high and low end tests so that more than likely just leaves the PCB. But I'll check out the other threads aswell always good to plug the brain with more info. Thanks again!!