Hy gents, This dammened machine certainly is cursed... Came from auction... Several lights on EMS were lit, and some of the gauges were not functioning properly... Managed to get everithing running except the alternator light does not extinguish. All fine with ALT and wiring, also i guess the alarm light does not blink... but it used too. Reading from a publication it was suposed to be a buzzer along with the alarm light? EMS light test fine. 2 questions , its possible to repair the EMS? if so does anyone have a wiring diagram of the box? Can someone explain the logic around this EMS Machine # 1DD05648 Thanks in advace.
I've never seen an illustration of the internal wiring of the unit. In my opinion they are not of sufficiently high retail value to make it economical for electronic repairers to attempt to fix them. Does the hourmeter work.? You mean when you press the test button all the EMS lights + the Master Fault Lamp flash.? Have you tried applying battery voltage to the Action Alarm horn to see if it works.?
My bad Yes, alt wiring was fixed and we have now ground with engine off and 28 with eng running in both EMS and hour metter wire. master fault does not flash upon test No i did not, it was not clear system had it
Do you have an electrical schematic.?
Yes i have.
From the schematic the Action Alarm is a separate component. You can unplug the 2-pin connector and apply Batt+ to Pin 1 while connecting Pin 2 to ground. If the alarm sounds then it is good but is receiving no signal from the Monitor, another sign that something is wrong internally in the Monitor.
I can do that. Anyway u have any idea wich lamps triguer the light and alarm, or one or the other. The indicator and alarm logic...
I'm sorry I don't. If a Monitor Panel went bad we would simply replace it.
The Alt light is on because the tach signal is not putting out. only solution I know is to get a OR from Cat I never found a rebuilder that would fix that part of it
What u mean by a OR? Tach signal, u mean alternator signal? buh, i mean wich lights would triguer the alarm? maybe all or just some , i guess it does blink for some cases and not all or is somehow has a timing delay switch... i wonder what logic is behid it... thanks guys
Genuine Caterpillar Reman alternator. Alternator speed (tachometer) signal on wire 403-GN. This is NOT simply a voltage signal, it's more complex than that. I have no idea how the Monitor panel works or what internal logic it uses. We worked on the principle of - if it works fine, all well & good. If it doesn't, replace it.
Ok , it might be traced then... the alternator is a OEM unit, but it was repaired for a voltage regulator fault, it uses now a china crap regulator. Probably its what´s messing around, either voltage is low or high , i don´t think the system is counting anything else, as 403 wire is shared with the Hour metter, U guys Implying it should see the AC sinowave instead ? like some thacho´s ?
Exactly.
sure i can fix that... i wonder how the hour meter will work then? don´t think its AC powered...
OR original rebuilt there is a wire on the back that just pushes on it is used for a tach reading
Well, i conected the 403 wire to one conection that has GWD when alt is off and 28VDC when its running ... as some other wirings are ... But there are the W conection there wich usually is the tacho signal... so in your words the W conection will kill the light? Well there´s nothing like trying ... i´ll post findings... thanks