M923a1 dead in the water,,,,

[chevy427]

No power to my 5ton...one day good next day dead....no power to the dash....nothing...read the forum threads and did the most likely...the 2 batteries in it have 12.5 volts....replaced the ignition then the PCB...still no power Im no electical genius by any stretch and any help would be very much appreciated!!!

 

[98G]

You replaced the master power switch? (Upper switch)

Jiggle the cable to post connection....

 

[marchplumber]

Got voltage from batteries? At switch? Tried slaving it off? I'm not an electrical guru either, but they ARE here on the site, maybe they'll chime in too.

 

[chevy427]

dead in the water

Got voltage from batteries? At switch? Tried slaving it off? I'm not an electrical guru eith er, but they ARE here on the site, maybe they'll chime in too.

Tested the batteries they both have 12.5 volts and they are alittle weak on the load test but still not bad still no power to the dash...just dont understand why good one day the next dead....would dash power come thru the starter selinoid? going to start trying to trace the power and clean all the ground connections...any insite would be appriciated....how do you slave it off? thanks!

 

[chevy427]

allso....replaced the "top" power switch and the PCB...

 

[marchplumber]

Suggest TM'S as reference. Start from battery and follow the 24volt? Weird from one day to next, but in my experience electrical doesn't give a lot of "warning". By slave off, I meant have you tried using a slave cable from one MV to another. (Imagine really large jumper cables) Slave port for 939 series is on passenger side just behind door opening.

 

[chevy427]

First and fore most Tony, God bless you to!!!been working crazy hours and haven't had time to mess with my 11 ton paper weight...Thanks for solving another mystery....now I know what the "slave" is and where it is at lol! I have nothing to jump it tomorrow Im going to start chasing the volts,,,and see where it leads...one person commented the most common problem he has encountered is the wire from the pcb to the starter cylinoid sooooooo I'll try and chase the power.....hope the New Pcb is good !

 

[marchplumber]

There are other threads here about the PCB box....might check into them. Still suggest referencing TM'S available here in site and go through the trouble shooting section. =) There's a lot of info....go slow....she's not goin anywhere and she's not in danger....send out a few PMS to other members who are more experienced. Frustrating as these problems can be, they are definitely a learning experience about these trucks. When the solution is found, be sure to share it here so others can benefit from your endeavor.

 

[marchplumber]

Any updates? Hope ya found the problem!

 

[chevy427]

God bless you to Tony....no not yet....cleaned all the grounds REAL good,,,but havent had the time...going to tear the old control box apart to see if any of the diods are burnt....Ive heard stories about new control boxes being bad....Ill keep after as time allows....thanks Tony!

 

[marchplumber]

Check out the thread about the PCB box and it's rebuild. Several members have done it and it is well documented here on the site. You'll get her running again! Take a look at the members map and ask a couple of members that are local to ya for some assistance. Most on here are willing to help those that try to help themselves! =)

 

[Andyrv6av8r]

Read this thread and check out post #21 about using a jumper to eliminate the PCB. It's how I found out mine needed rebuilding.

http://www.steelsoldiers.com/showthread.php?113634-Ever-see-inside-the-Protective-Control-Box/page3

 

[marchplumber]

Do you have any solution to this yet?!??! Always nice to put a "conclusion/problem solved" on a thread whenever possible. If not, what are you working on next as far as gettin her up and running?

 

[chevy427]

Hey Tony,
Sorry for delay! Got her running! Ultimately it was the brain box...gonna try and rebuild the old one so I got a spare...In all my charging and cleaning batteries I got them hooked up wrong and had no ground... Got that straightened out and she runs! 20 minutes latter I was stuck on a sand hill High sided on the frame! Nothing a day with a idiot spoon didnt solve lol! thanks for every thing Tony and God Bless you and yours! dirk

 

[marchplumber]

Glad you got her running! Haven't heard that term, "Idiot Spoon" in quite a while! ENJOY the truck!