What does the control box in a 900 series 5 ton actually do?

[jonsm114]

Control box....what does it control?

Jon

 

[usmcm35a2]

Prevents the operator from engaging the starter again once the truck is running.

 

[Stein12501]

I had problems with mine when I picked up the truck. I opened it up and mine contained 2-24vdc relays. One was for the power switch and one was for the starter relay. I will try and post pic of mine. Where in St. Louis do you live?

 

[jonsm114]

Defiance....Just picked up a 5 ton Tractor in Jefferson City.......

 

[Stein12501]

Yes I live across the river from Jefferson City. I've picked up my Deuce and 923 both from JC. My aunt used to live in Defiance. Was you truck batteries dead when you got your truck?

 

[commandojeff]

Jon, Have you put the charger on your batteries yet? Also check their voltages while you have them out.

I have a spare box that will work to get an idea if that is the problem. Let me know, I can try putting it in tomorrow morning if the weather shapes up. It doesn't take long to do.

 

[jonsm114]

Oh yeah./......JUMP in chalk on the drivers door......alternator inop, guages inop.....other than air....oil pressure....

ran like a scalded ape......drove her home to St Louis after getting a jomp from the yard boss.....

Jon

 

[Stein12501]

Yeah Jon mine had JUMP written all over it. They jumped it in the yard and off she went. All of my gauges worked though and I showed a charge but as soon as I shut it off she was dead. Replaced 2 batteries and still had problems. Found it to be the lower relay in the PCB. I know that the power switch energizes the lower relay that supplies power to all of the gauges, alt and the upper starter relay. At least that is the way mine is set up. Most of the PCB boxes are more elaborate. Is commandojeff going to let you use his spare that would be an easy fix or at least know if that is the problem. If not let me know I can pull mine and meet you somewhere and you can try it. I live a mile off of 94 but at the other end. Let me know.

 

[steelandcanvas]

If you do a search for the 5 ton 800 series control box, you'll find a very good article written by Cranetruck, complete with schematic.

 

[diesel dave]

When replacing batteries in heavy trucks,you should always replace them all. If you don't ,you will likely continue either now or in the near future,to have battery problems. This advice was given to me years ago by heavy diesel mechanics after doing the same. I was constantly replacing batteries in a truck-chasing my tail -until a mechanic talked me into replacing all.

 

[jonsm114]

Thanks Stein........going to test and charge all batteries.....reinstall them and then attack the control box.......I have been told to tap it, and see if it will get the relays moving...lacking that, I am going to install Jeff's spare and give it a try.

I will post the results...

Jon

 

[Stein12501]

Sounds good Jon. In my case the relay would energize when I would flip switch off it would not de-energize draining the batteries. Bought new relay from golf cart shop works great. Sad thing was all four batteries were trashed. Bought 2 new ones and now running it on 2 batteries instead of 4. Let me know how it comes out.

 

[jonsm114]

there were broken alternator belts under the hood....I figure it just ran out of juice..and had to be jumped. the control box was not sending current to the alternator. I have started charging the batteries. Individually, 10Amps ...for a day or so then drop back to 2 amps for the rest of sunday and monday. Will load test the batteries Tuesday to see what I have. if they test out...cool..if not...I have several new group 24 batteries with threaded studs that will do the trick....

Stay tuned......

Jon

 

[commandojeff]

Jon, another thing I noticed is that I don't hear the normal clicks when turning your run switch on. I think that has to do with your ABS light staying on. Another member had that issue and I read about it a couple weeks ago. If I track it down I will let you know. I can't quite remember what the fix was. I read so much stuff on here that it all blends together... We will get it running... Well... it runs great! We will get it starting I mean .

 

[rrrr]

Jon, congrats on the new truck. Look forward to seeing it at a few events this year.

The abs light will stay on if you don't get a good self check. This could be a result of the battery/alternator issue since the unit needs I believe 21-31 volts to operate; I need to look in the manual. I have the abs diagnostic control unit so if you still have problems we can plug your truck in and get the codes.


These trucks need 4 good batteries in cold weather to start up. Just the nature of the big NHC250. I put a block heater in mine and it works great. My 4 new batteries also helped on the cold days.