I can't find the voltage regulator anywhere in my shop manual for my Dash 3. Anybody know if these models have an external regulator or internal in Alternator? And if it is external, how I test it? And can an alternator just get a little bad without failing completely? My alternator is showing slightly low voltage output (approx 25 volts) when i put the multi meter on it. When I load the electrical with the heater it seems like the alternator can't keep up to keep the batteries charged. I'm not sure if its the alternator or regulator. I have new batteries. Do you think the alternator being a little low would cause this? I have a slight parasitic drain in the system as well, not sure where yet, I'll pull the fuses next weekend. Thanks!
Ok... Anyone know if 26 volts from the alternator is acceptable? That's what I have from the leads on the alt, but the batteries are only barely showing higher voltage when the engine is running and actually drop slightly with just the heater blower on. I put my multimeter in series on the battery cable...it's showing .7 amps when everything is off...think this is enough to keep the alternator from being able to maintain the batteries?
26v might be acceptable. It sounds like either your alternator is dying or else the batteries are very low on charge. 0.7 amps will drain the batteries in few hours, so that sounds like the main problem. Easiest to start with charged batteries and see if the alternator will keep up with the accessories, but it sounds like the alternator is struggling to "refill" the batteries and can't put out enough to handle any load at the same time, that's assuming you had only recently started the machine and were checking it right away, not after running for hours. Most likely the regulator is internal. And an alternator can be a little weak, but I'm betting on the batteries being drained, unless you tell me the machine runs all day and won't get a higher voltage. edit:maybe that would be a few days to drain, but .7 amps is still a LOT of drain.
Awesome info, tks. One battery is less than a year old, the other is barely 2. I ran the machine for several hours last weekend with the heater running the entire time. I turned it off and it wouldn't even start back up again. So I'm guessing it's my alternator. I pulled each fuse today as I watched the volt meter, but couldn't find the source of the .7 drain. Bugger.
Yep that's a bad alternator, assuming the alternator is hooked up correctly, and the batteries will hold a charge. If you pulled all the fuses and still had the same drain, that's the alternator diodes that's leaking most likely both when off and not putting out when it's running. If you want to mess around with it you could replace just the diodes, and you could even diagnose it for sure on the machine (I can look up the steps), or if you can figure out how it hooks up you could replace it with a cheaper alternator. If it's an original Denso alternator, I'd fix it myself or find an auto electric rebuilder who can give you the same one back, just don't get a cheap "new rebuilt" or you'll be pulling it again in a year or two.
I'll check the price of it today or tomorrow. How difficult is it to replace diodes or diagnose? It is a Wilson 0-33000-5860, not sure if this is OEM or not. Thanks again for the info, its a great help! Here's a pic...
Wilson looks like an aftermarket rebuilder, doesn't look like they're OEM. So that's either a denso, delco or other OEM that's been rebuilt, or its a Wilson copy of the original. Might as well replace it. If it was the genuine article, it might be worth replacing the part to keep your other good parts... Not too hard to diagnose if you can identify the terminals and use a multimeter, pretty easy to take an alternator apart and replace parts, the hardest part is usually getting the alternator out of the machine, unless one of those long skinny bolts has become one with the aluminum body and snaps off.
Well, I did some shopping today... The Wilson alternator, which is a popular aftermarket maker in Canada, ranged from $340 to $550 at Komatsu dealer, NAPA and Carquest. The OEM alternator is $600 from Komatsu. A quick look on ebay got me a Nikko (a reputable aftermarket brand) for $126 plus $40 shipping! SOLD. Thanks for the help Delmer, hopefully this cures what ails me.
Yes the Komatsu uses a internal reg and when they give up it will drain your batteries down but you have solved that with your new alt. Komatsu also used to put a saftey sol on the hoes so when they were running the starter could not be engaged that little bugger also gave you grief.
New alternator installed fixed the problem...also, noticed the water was down in a few cells, most likely from having to charge batteries so much over the winter due to the crappy old alt. Topped those up as well and good as new. Thanks for the help.