I have morooka mst 2200vd s/n 223690 I am having issues with the parking brake alarm and the shift button. The light for the p/brake doesn't come on even on the initial start up-light check neither does the shift light. The gauges are starting to act up too, they are starting to not register. It is acting like a ground problem, but I need a wiring diagram to make sense of it. I am open to any suggestions
Hi Chepe, I have what I think is the correct schematic and parts book for that machine, but it's six separate PDF files part CAT, part Morooka. That has the C7 CAT engine, correct? Give me a little time to study these sheets, I'll see if I can help. First guess would be there's an interface module, CAT number 274-8068 on the right side wall of the cab I think, funny looking thing like a half circle kind of? Has two six wire plugs. One of those carries power and ground for those two lights and the three gauges. Probably just a loose or overloaded pin. If you can locate it, on connector J1, pin 1 is a red wire, that's power in to the module, pin 6 is black wire, ground. The outputs are on connector J2, pin 4 is gage ground black wire, pin 5 is gage + red wire. Here's the parts book in case you don't have one to start with, you can find the module by searching the part number: https://www.dropbox.com/s/fp19lcyqwxik3dg/MST-2200VD_223101-1-1.pdf?dl=0 I'll be back......
I found the interface module, and I do have power coming in but I don't have power going out to the gauges. Would that also affect the brake buzzer? Right now the machine starts but gauges are stuck, fuel at full, volts at low and water temp at the low end.
Are you having issues with the two speed shifting also? The two speed control unit and the parking brake buzzer are (don't ask me why) grounded back through pin 4 of J2 on that module along with all three gauges and the brake and Hi-Speed lamps. Pin 5 supplies power to the Temp and Voltage gauges. Sounds like you lost both power and gage ground. You might want to check the two indicator lamps, if the bulbs are replaceable make sure one of them isn't shorted, might have taken out the power supply and ground? The good news is I think the CAT part of the system is fine, this interface module supports the gauges and indicator lights for setups that don't have a monitor screen. I'll try to get these sheets uploaded to Dropbox so you can have fun following these silly circuits too.
Yeah the 2 speed is just making a clicking sound from a module bolted to the back. I already checked the bulbs by doing some trading with the ones that are lighting and they checked out ok. So are you telling me that the power supply and ground coming out of the module is bad? Telling me I might have to get 274-8068 module from cat?
I've started a new thread, hopefully one or more of the CAT guys that have SIS access will be able to give us more info on that module and the power it puts out. Any markings on the gauges as to make/model/voltage? I will give you this warning before I suggest this, I don't think it will do any harm, as it's ground, but I can't swear to it... you might try grounding the wire from pin 4 of J2 or jumpering it to the wire connected to pin 6 of J1 which is battery ground. That should clear up half the problems I think. Then we just need to figure out what voltage the gauges actually run on, might be just raw 24V or it could be regulated 5V, sadly the schematics don't show it, but if the lamps are all the same bulbs I would guess raw 24V.
Here's the pinout but unfortunately, no voltage. I can't find any specs for it or for the gauges that it runs. I would be very reluctant to try powering the gauges with battery voltage. As you suggest, I would think 5 or 8v more likely.
Thanks Cmark, more sleuthing will ensue. If I had a machine handy I would sally forth with DMM in hand and ascertain the truth....
The module is commonly found on M series graders so if anyone out there has one in the workshop and can check the output voltage............?
Tomorrow I will try running a ground to pin 4 of j2 and see if that fixes the problem. I will let you know. Thanks guys.
Did you double check for a good ground on pin 6 of J1? I know you said you had power, but did you ohm the ground wire to a chassis ground? Just curious.
I'm with Cmark. If the gauges ran on battery voltage there wouldn't be any need for the interface module. Most likely the output is 5 or 8v, but I would think in the case of this module it would be a digital supply even though it doesnt explicitly come out and say so. TBH i'm not even sure you can guarantee that the ground on J1 pin 6 will be even connected to the ground on J2 pin 4. You could try it with a DMM but don't be surprised if it comes out as open circuit. These electronic whizzbang boxes can have all sorts of weird **** in them, so take nothing for granted IMHO. I agree with lantraxco, make sure you have a really good connection to ground on J1 pin 6 before proceeding further.
Nige, you may well be right, but on the other hand this setup converts J1939 to a serial bus for analog gauges and the harnesses daisy chain from this unit to a string of gauges. The power and ground could indeed be regulated with all sorts of circuits or it could be nothing more than copper traces direct from one connector to the other. Lacking the simple courtesy of noting a voltage on the schematics, hoping someone can slap a meter on one that's working, lol. I think these gauges and such are actually Murphy with the CAT logo on them.....
Here's the link to the schematic sections, quality is not the greatest but better than not having them: https://www.dropbox.com/sh/ux0cz8cow8vkapf/AACmDY_Qu946z1RrOjromx9Pa?dl=0
Lantraxco you know your machines, putting ground to pin 4 j1 gave me back my gauges and my two speed switch and light, however now my parking brake is tripping the 10 amp fuse. When I replace the fuse if the parking brake is off it survives, but the minute I put it on to start the machine it blows. Guess I am going to have to trace a circuit to see where it is rubbing.
Hmmm. dammit there's some sheets missing from this schematic :Banghead The brake solenoid takes power to release the brakes, I *think* the only thing drawing power with the brake ON is the silly buzzer and the lamp in the panel. I think the buzzer is in the plastic below the gauge panel? Check the lamp wiring and disconnect the buzzer if you can find it. This short is probably what took out the ground circuit in that module. There is an interlock to prevent you from starting the machine with the brake OFF, so that may also play a part, but I'll have to see if I can get somebody to send me the rest of the schematic to trace that out.
I will find and disconnect that buzzer tomorrow. These machines are impressive, we have four on site three cats and one cummins the cats seem to be unstoppable but the cummins is having dpf issues. Thanks again the help is much appreciated.
Hey, we do what we can, always happy if I can be helpful..... I guess you can't win with the new engines, one dealer I talked to back in Mississippi I think said roughly a third of their CAT powered machines had had major issues at 2,500 hours and below, mostly valve/head issues. Cummins is supposed to be the Tier 4F answer.... Where you working at, and whose machines are they? Just curious, lol. Let us know what you find!
We are working in the redding area. As to who's machines they are I don't know they are rentals but they don't even have stickers on them of the parent company.
Probably rerents sourced from the Morooka distributor, but you never know, it's a funny system... Rode through Redding a time or two, what kind of project is it, reclamation, or?
We are stabilizing a slope under some transmission lines that began to slide last year for pg&e. I am told that we renting from a guy in Texas who calls a company in Virginia who stores some morookas in Oregon. Like you said it doesn't make sense. By the way the short was the buzzer. I disconnected and everything worked as it should. Thank you for the help.
As a matter of interest could you measure the voltages that was the subject of earlier posts Mark
Okay, sounds like an interesting job, if you get the chance how about some pictures? Yeah, it's the wild west with these things, lol. The distributor does have a warehouse and yard in Portland, they get machines and parts from Japan through Seattle. Isn't that crazy? Shorted buzzer, and the ground carried less than the 10 amp fuse. Wow. Glad we got it, good job!