939 PCB help

Steel Soldiers is supported by:

gimpyrobb

dumpsterlandingfromorbit!
Steel Soldiers Supporter
27,655
217
63
Location
Cincy Ohio
I was contacted by a member that needs some help and I am not very versed in troubleshooting the 939 protective control box. Here is what I was sent:

My symptoms: With the PCB box unplugged, the switches in off position, battery cable unhooked, I get the following when I connect the battery cable: ABS warning light on, Low Air Light on and buzzer, Parking Brake light on.

Other information: Several
month ago I drove the truck everything was fine. About a month later went to drive it and the batteries were dead (switches in off position). When I started charging the batteries as they got energy I got ABS warning light on, Low Air Light on and buzzer, Parking Brake light on.
I was able to start the truck and everything seemed to be in
normal state no ABS light, no Low Pressure light, No parking brake light when put down, when the air came to pressure the warning buzzer went off. I could drive the truck everything seemed normal. The only problem was that the switch would not turn the engine off. I had to pull the emergency shutoff to stop the running engine.

I thought when the PCB was unplugged I thought nothing had power but guess I am mistaken in that thought. I did try a PCB that died on another truck, would not allow the truck to start, and got the same failures.

I also unhooked each wire from both switches individually and the symptoms did not change.

Where do I start or need to look at please? My son-in-law the mechanic is not available to help me right now but I do have good basic skills.

Thank you for your time and help.



If anyone could offer some help, I would really appreciate it.
 

fuzzytoaster

Well-known member
Steel Soldiers Supporter
3,603
268
83
Location
Fort Worth, Texas
If it's acting the same even with a different PCB then I'd look into a potential wiring issue or if the power switch has been bypassed. If this truck is an RRAD "overhaul" it would not be the first PCB wiring issue like this. Start tracing.
 

lstmate

Member
302
0
16
Location
Jasper, IN
Up date on trouble shooting for this problem..... On the positive terminal there is the + side for the slave receptical, + cable running to starter and one other wire looks to be 12 gauge. When this smaller wire is removed from the connection the buzzer and lights stop. I did not have time to finish some more trouble shooting tonight (reinstalling switches and starting the truck and see if the switch will turn engine off, trace outwire) will get back at it tomorrow.
 

lstmate

Member
302
0
16
Location
Jasper, IN
OK here is the latest update... Today I tested the truck with wire #68 disconnected from the battery. The truck started and shut down without and problems. I traced out #68 itgoes straight to the diagnostic plug under the dash on the passenger side. I found 2 bare wires not connected and suspect several other wires bare and disconnected in the diagnostic plug. My plan is to pull the plug out and verify everything is insulated and leave wire # 68 disconnected in the battery box...

Thoughts or suggestions????
 

lstmate

Member
302
0
16
Location
Jasper, IN
20170702_152156.jpg20170702_152156.jpgMy diagnostic connector delete complete. removed all wires form the connector and put heat shrink tubing on each wire.
 
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website like our supporting vendors. Their ads help keep Steel Soldiers going. Please consider disabling your ad blockers for the site. Thanks!

I've Disabled AdBlock
No Thanks