... my CAT 416B, which won't start. Battery is great (12.6vdc, lives on a batt conditioner) batt connectors are great, but all I get is a rapid click that sounds like a snare drum when I turn the key. Somewhere between the starter relay and starter itself there be a problem. Anybody want to place bets?
Do you have an electrical schematic to help tracing power.? If not would you like one.?
I have a factory service manual, so I'm hoping it's in there somewhere? But I'll take whatever you've got for sure
In a paper service manual it will be a fold-out schematic maybe 36" x 24". In a digital SM it will be an Adobe pdf file with the same info.
It's an old manual (got it used) and it's definitely NOT in there. But I'd definitely be down with a PDF
A Serial Number gets you the correct one for your particular machine.
8SG05798
On the way. Check your messages.
Did the problem start out of the blue? or was there anything leading up to it? or any work done that could have contributed? Have you done any voltage testing under load? or how did you determine where the problem is already? I'd start with battery voltage under load, then move to the starter voltage under load. Should narrow it down fairly quickly.
The problem was kinda progressive over a few weeks. Occasionally I could get it to start, but now it just does the fast clicks. I've haven't load tested the battery myself, but I did take it to my local Batteries Plus store, and they did a 24-hour charge and test thing. They said it's fine. It's not too old, so that makes sense. I do notice that when I try to start it and it makes the super-fast clicks, the voltmeter on the console (which shows about 12.6 vdc with the key on) drops to virtually nothing, bouncing back and forth with each click.
That sounds like a bad connection somewhere if the battery checks out. By testing voltage under load, I mean to run some test leads to the starter for instance, hook them to a multimeter in the cab, and see what the voltage does when you turn the key and get the rapid clicking. If it's fine, move the test lead to the signal wire to the solenoid, keep moving based on what you find.
I'll take a faulty ground for $400 Alex
A few simple measurements and you can diagnose the problem instead of guessing. 1. Put a voltmeter on the battery and crank. if it goes below 10volts, time for a new battery 2. Put meter on DC volts. one lead on Battery positive the other on the positive battery connection at the starter. Crank and observed the voltage. If above 1 volt or so you have a bad connection from the battery to the starter. 3. Now put meter on DC volts. One lead on battery negative the other to the case of the starter. Crank. Again above 1 volt is bad. With those 3 quick checks you will know what is wrong. Bad battery, bad positive connection or bad ground. By the way @Vetech63 's guess is a suckers bet. Most likely is a bad ground but battery can be toast too.
Ah yes .... can I even count the number of times I've lost my mind and torn out my hair over some intermittent electrical gremlin that defies all logic, only to remember (too late) to just check the ground BEFORE I start taking everything apart? In this case it was solid and tight and looked perfect (even had all the original yellow CAT paint) with no corrosion visible at all ... until I removed the bolt and found rust on surfaces of the washers, and on all the threads (outside AND inside) so cleaned and polished it all and put it all back together and of course it fired right up. $400 for the win
LOL.....about time I had a win on this forum!