I have a 55 1/2 ton w/BBW 235/3spd w/OD. I replaced the wiring harness with a new one from classic auto with the original wire colors. Everything works great except after starting it discharges the battery. If the battery is disconnected after starting, truck runs fine. Everything is new or has checked out, generator/voltage regulator etc. All connections have been quadruple checked and I have verified multiple times that each wire is where it belongs. As I said, all lights/horn/guages/radio/heater/turn signals work fine. Anyone have any ideas? I'm at wits end and have worked on this for 3 years and would really love to get this on the road and drive it? Thanks!!!
discharge From what you tell us, you have a generator and it must work with the battery unhooked as you drive, that means the generator is working. Normally, if a generator is turning, it is charging, with nothing to control it, it will charge wide open, the voltage regulator does that job. I have never heard of a problem like this before but I will give you my opinion anyway for what it is worth.You said this started after installing the new wiring harness, if everything else is working properly then it would seem like the problem is in the harness. Sounds like something is grounded and shouldn't be. When it is parked and not running, if the battery is hooked up does the battery run down? Good luck, don't you just hate wiring problems? Gerald in Florida
Does it run fine but show discharge on the dashboard ammeter ? . Maybe the ammeter wires are reversed , easy to check by watching the voltage at the battery ~ after starting it should rise to 13 +/- VDC above idle . Once in a long while the generator gets reverse polarity , usually from someone trying to ' polarize ' it and making sparks like a welder instead of the 1/10th of a second touch it needed...
Ampmeter is new, shows minimal discharge at idle, increases discharge amount with speed, generator has be polaraized, wiring connections checked/reverified including connections on ampmeter. Old wiring scheme had 2 wires to ampmeter (one red on passenger side/black on drivers side. The new harness had two connections (red) on passenger side/one black on drivers side. I checked the repair manual, the wiring diagram showed 4 wires, an additional 12 guage black wire from drivers side of ampmeter to the starter/positive battery cable hookup so I tried this fix, it made no difference. All parts in the charging system (Voltage regulator/horn relay/starter solenoid/ampmeter are new. The only not new part is the generator itself and I had it checked out and it works fine. Any other ideas?
Basic Questions So then ; It runs fine but always shows a discharge ? . Y/N Does the battery go dead when you leave it parked ? Y/N TIA ,
Yes it runs fine, and yes it shows discharge on the ampmeter while running. No it does not discharge when not running.
One More Question : If , when the engine is running above idle speed , you disconnect the ground battery cable , will it die or keep running ? Y/N . WARNING ! : when Field Testing the charging system by disconnecting the battery ground cable , you must never , EVER allow it to touch the battery again until you've shut off the engine ! . Tuck it down behind the battery then go turn off the key or have your assistant shut it off and do not touch the cable to the battery post until the engine is at rest .
I don't want to steal Nate's thunder, but can I guess at the answer????? There is one more question that Nate will ask that will nail down the answer for sure. By the way, I really like the way you diagnosed the problem Nate.
Thanx Bill ; I had mucho onions for lunch so the thunder , you really don't want it . ASK AWAY my Freind .
Engine off. Observe ammeter. Turn on headlights. What difference on ammeter? I'm betting it is showing a charge. If so, ammeter is wired in backwards. By the way, this answer is from me in Taipwan. I leave for the States tomorrow morning.
The Answer BINGO ! . I hope you have an uneventful trip home . I'd certainly love to go there where Mass Tiddlers are to be found......
" Tiddlers " ...Is a word from Jolley Olde Englande , it means Motocycles with one cylinder engines of not more than 100 C.C. displacement . Most Countries apart from America , figure the license tag $ on the engine displacement , this means everywhere but America , 100 C.C. or smaller Motos are the most popular . Anywhere in Asia , you'll find scads of tiny Motos clogging the roads . As it's impossible to be overly serious or whatnot on one of these tiny things , I find riding them to be much fun indeed and have quite a few my ownself . I often Tour the Desert back roads , going to Death Valley from Pasadena and so on as there's much to see when puttering along @ 35 ~ 45 MPH .
