5 ton just clicks??

[Augdog1964]

Hey all,

Well my M923A1 is having an issue. I turn the master power switch on and instead of the "initialization" sound you normally hear, all I hear is a single click... then when the starter switch is moved up, nothing happens. Batteries are new... any ideas?

 

[commandojeff]

PCB box. Protective Control Box located on the firewall, left side to the driver. Right behind the ether can. You can smack it with a hammer while someone else starts the truck. It is the solenoid inside that box that is bad... usually.

 

[commandojeff]

Some things I might add as well. My ABS light started turning on every time I drove the truck. Then my PCB box was acting up, so I replaced it. Now my ABS light no longer comes on... weird.

Do your gauges not flip over when you turn the main power on as well?

 

[Derrickl112]

The PCB box. I had the same issue with my m939.

 

[Augdog1964]

Thanks guys!

Anybody know where I can get a PCB box!

Thanks!

 

[Augdog1964]

Gauges

No my gauges do not cycle or do anything...

 

[davey8943]

Augdog,

Erik's surplus sells them:

www.eriksmilitarysurplus.com/elcoboxform9.html

at $345 they are a bit pricey.

I have seen them for sale on ebay and a few other places, but no where that is readily and usually in stock..

Happy part hunting!

Dave

 

[Augdog1964]

Thats half the fun, or is that half the frustration? LOL!

You guys are the best!

 

[pad_cdr]

This may be a dumb question, but did you actually check the batteries with a volt meter? I've had new batteries (and starters and alternators) go bad.

 

[73m819]

As much problems the PCBs cause WHY not get rid of it, really in the 900s, all it is is a NEUTALE SAFETY SWITCH and ENGINE ROTATION NO START SWITCH (oil pressure switch), along with a master power on/off solenoid, I am sure you can here the engine running and know better to start in gear, if you want a neutral safety switch, that would not be hard to rig, what ever is done it could be a couple of solenoids mounted on the firewall where it is easy to get to to fix with EASY to get parts.

 

[wsucougarx]

I bought my PCB box off e*ay for $130 for my M923. It is being sold from a CAGE manufacturer who makes them for the military.

 

[wsucougarx]

Due to site rules, I cannot give you the direct link but it is sold by member "cage-1y875"

 

[commandojeff]

Smack it with a hammer. It will start .

 

[Augdog1964]

As much problems the PCBs cause WHY not get rid of it, really in the 900s, all it is is a NEUTALE SAFETY SWITCH and ENGINE ROTATION NO START SWITCH (oil pressure switch), along with a master power on/off solenoid, I am sure you can here the engine running and know better to start in gear, if you want a neutral safety switch, that would not be hard to rig, what ever is done it could be a couple of solenoids mounted on the firewall where it is easy to get to to fix with EASY to get parts.

WOW, if you can tell me how to do that, I'd be game! I'd love to get rid of the whole thing...

 

[commandojeff]

Can you just short out the solenoid? Seems like that would get rid of the problems all together.

 

[doghead]

I bought my PCB box off e*ay for $130 for my M923. It is being sold from a CAGE manufacturer who makes them for the military.

That seller is only listing one PCB, with an NSN of 2920-00-472-1642, and that is not the correct PCB for an 923 truck( it is correct for an 809 series truck) and they are not interchangeable, both ways. You can use a 900 series PCB in an 809 series truck, but you cannot use an 809 series PCB in a 923 truck.

 

[73m819]

WOW, if you can tell me how to do that, I'd be game! I'd love to get rid of the whole thing...

PM sent, call me

 

[davey8943]

WOW, if you can tell me how to do that, I'd be game! I'd love to get rid of the whole thing...

If you can get 24 volts to the selonoid on top of the fuel pump (the one that opens to allow fuel to the injectors), the engine will start by jumping voltage across the starter selonoid.

I have been starting my M934 like this for a few weeks now, until I can get a replacement PCB.... I'm not sure what running the truck without powering the ABS will do to that system though. My battery and run switches work, I just don't get any cranking when i engage the momentary switch to run the starter.

YMMV

Dave

 

[juanprado]

Abs draws power from the PCB so those issues can be the same problem.

 

[Augdog1964]

Well went out to the field where she was stranded, took a wrench and smacked it a few times, it ended up initializing and I was able to start her...

Just what is in that thing that hitting it would make it work? I'm not Fonzy that's for sure!