M923A2 Starting issues

[TURKEY131]

I have an M923 that I have not been able to get it running since I picked it up. I am new to 5 tons and have been reading the TM's but have not been able to come up with anything. I have been searching though different threads and have not been able to come up with anything. My issue is that the starter is not engaging when I hit the switch. I thought it may be the starter so I replaced it. It was a bitch of a job. It took me about a total of 4 hrs and as nothing but a hassle. So after all that I went to try it out and nothing. The truck powers up and I hear a couple of clicks, when I go to engage the starter all is I hear is a click and nothing. I am stumped any ideas would be greatly appreciated.

 

[MtnSnow]

Have you tried engaging the starter with a mechanic's manual starter switch? aka Remote Starter Switch

Have you checked out the PCB (protection Control Box) to see if it's working correctly?

 

[plode]

Just looked at the electrical system on the P2P software. Looks to me like it would either be the starter solenoid or the protective control box(black box on the firewall). Personally, I'd check the solenoid since you said you're still getting a click. The click you hear is typically the solenoid. Sounds like power either isn't getting through the solenoid.
That, and the obvious, you have good power from the batteries to the solenoid, right?

 

[TURKEY131]

Plode that for the input. I replaced the starter with a brand new one so I hope it's not the starter. When checking the starter how would I check to make sure the starter is getting power?

 

[searls84]

My 923a2 had the same symptoms, power, click but nothing at the starter. I could start it by crossing the terminals at the starter solenoid but not by using the switch. Long story short, I ran a wire directly from the small terminal on the starter up to the start switch and problem solved. So maybe check and make sure you are getting power to starter when you turn the lower switch to the "Start" position. If not you may have a bad wire.

 

[plode]

Plode that for the input. I replaced the starter with a brand new one so I hope it's not the starter. When checking the starter how would I check to make sure the starter is getting power?

On the solenoid, there are three essential wires connecting to it(there might be a few more, but they aren't required for the starter to crank). One hot all the time, one to the starter, and the "signal" from the start lever(through the PCB box). The solenoid is essentially a big relay. Get out your volt meter(I guess a test light would tell you what you need to know too) and check the one terminal on the starter solenoid to see if it's getting 24v constant. Have someone hit the starter while you check the other terminal for 24v. If power is getting through to the other terminal and it's still not cranking, then I'd suspect the starter is bad(also check to be sure the engine itself isn't locked up). If not, then check the "signal" wire from the start lever while someone engages it to see if it's getting juice. If it isn't there might be an issue in the PCB box or at the start lever(if all of the wiring is in good condition).

The more I read on here, the more I suspect it'll end up being a bad solenoid inside the PCB box.

 

[TURKEY131]

(UPDATE) Today my neighbour and me went to try to figure out this starter problem. I was getting 24 volts with the switch off. With the switch on I was getting 19.3 volts at the small starter wire. When I checked the top log I was only getting 1.3 volts. We tried jumping the terminals and oh boy did it spark. Even with the wrench firmly against the terminals it was still arcing. With this all being said I am not sure where to go from here. We were thinking of bench testing the older starter but ran out of time today. Any ideas on what to try next?

 

[ClintA]

I am having the same problems with a new to me M931, it was running when I shut it down for the night and the next day it will not even turn over, It was overcharging when I shut her down and now I am scratching my head wondering what I do next? I put 4 new Batteries in her, I get my guages to come on and hear a "click" my ECU light comes on then goes back off, but no crank, therefore I subscribed.

 

[Hawssie]

These trucks ignition wise are about as simple as they get except for that control box. I know its too late now but you should try and jump start it first before buying or replacing the starter. At least I would. I was messing with mine today because I need to pick up another A2 that says its not running and since its 350 miles away I figured I may need to be ready o go around the ignition system at least to get it out of the lot. I was able to start one of my current trucks with one 8 "zip tie and a crescent wrench. Zip tied the kill solenoid up and jumped it with the wrench and it fired right up. Mine didn't spark but if it gets a chance you could be arc welding so be careful, it will spark a lot more due to the 24V. Of course make sure its out of gear and the E brake is on first. At least you can hear her run that way and get more motivated. Also one of mine has the opposite problem in that it doesn't always want to turn off with the switch. Sometimes it does sometimes it doesnt. I haven't messed with it yet, just using the pull stop for now.

 

[thesledge]

I had a similar issue on my 923A2 and it ended up being the Protective Control Box. I ended up taking the box apart and came to find that moisture had got into there. So, I took apart each of the connections and cleaned everything up in there and then put it all back together. This fixed my strange electrical issues. I am not sure if this would work on your 923 but i figured it would be at least worth sharing if it could possibly help.

 

[5tonman1971]

Do you know where your clicking is coming from? Have soldier B listen to the control box when you try to crank it. If the control box is clicking then you need to replace it. That should solve your problem. The control boxes are a 1/3 the cost of a starter

 

[aheilmann68]

Pcb failure. Are the clicks the abs system proving? One of my trucks intermittently would engage the starter. Rebuilt the pcb as the control boards were shot with the solder bridges delaminating not a single problem since.

 

[74M35A2]

This should be fairly simple. Begin at the starter. It should have 3 connection points to it (but possibly more than 3 wires total). Grounds on the very back of the starter which go directly to battery "-", positive cable on the starter solenoid which goes directly to battery "+", and a smaller gauge wire which sends 24V+ to the starter to be engaged.

As long as you have 24V+ on the positive, and 24V- on the grounds (check with meter, including when trying to crank), then you can run a jumper wire right at the starter from the 24v+ connection to the smaller solenoid connection, as others have mentioned. This removes the protective control box and the ignition switch out of the equation.

If all you are getting is a firm "click" at the starter, then possibly the engine is locked up. "Mis-enagagement" happens in heavy duty applications 1-3% of the time, which is a tooth-tooth flat interference as the pinion gear is extended out via the solenoid, but without meshing. Usually on the second attempt, it is fine though. Rotate your engine over slightly to make sure it is free. Also make sure all of your battery cable connections are tight on both ends, and the batteries are up to snuff from a charge perspective. Check the cables which connect the batteries together also.

 

[Jatsfirebird]

I've been reading this, I'm new and have the same problem. Where is the box on the firewall?

 

[simp5782]

I've been reading this, I'm new and have the same problem. Where is the box on the firewall?

Drivere side black and square behind the washer bottle