I got alternator problems. Here's what's up:
I got my 720 about 6 months ago. Shortly after buying it the battery died on me. It was an old battery so I had it replaced under warranty. After driving it a few more times though the battery died again. I got the alternator tested and folks at the auto parts store said it wasn't sending any charge to the battery. So, I bought a new alternator. After I put it in I figured it was fixed. I drove it around for a bit, pulled into the driveway happy as can be, and turned my key to the off position but, when I did the car kept running. I was freaked out like my car was about to go "Christine" on me and kill everyone I loved. But I kept my cool, popped the hood, and got out to have a looksee at the engine bay. Everything looked normal, nothing weird happening. But I needed to shut the truck off so, I disconnected the battery. And then I was really concerned. It kept running. What the DUCK!? My car is alive!
I scratched my head for a second and thought deeply, "what...the....duck?" Frantically, I got back in the cab, put it in gear, and let off the clutch to kill the engine. To my relief, my truck was not a sentient psychopathic killer and it cut off.
But I still had the problem of it running when I turned the ignition switch off. I figured there might be a bad connection in the old key/ignition switch so I ordered another one offline. It came, I installed it, and again it wouldn't cut the engine off when I turned the key to OFF.I called my car Dr. pops and we realized if the car is running and the alternator is sending a charge to my mechanical injection pump, that'd be enough to keep it goin since it's diesel and it doesn't need a spark to ignite fuel. It was time to trace the wires. I traced a wire off the alternator, a blue & white one, to the mechanical injection pump. Bingo! And on talking with my knowledgeable father, we decided we'd detach that wire from the terminal and see if the truck would cut off without it. It worked!!! I E-taped the blue & white wire up to stop current and then taped it down to the wiring harness so it'd be secure.
I drove it a few more times and again the battery died. This time on the winding mountain road to my parents' house.
I pushed the car around with help of a passer by, ran it down hill, and popped the clutch. It turned over but didn't have enough power to propel me across the terrain. I hitched a ride home with a cop. Not the kind of ride I like taking...Nonetheless, I got home, went and took my battery out, charged it over night, and retrieved my steed in the morning. So this is where I'm at. I'm lookin at my alternator, there are three wires comin off it goin into a three prong terminal that hooks to my truck's wiring harness. (See Photos 1 and 2 below)
The terminal on my truck's wiring harness, the one I pulled the fuel injection pump wire from, now has one prong left. That wire is not leading to the positive battery pole. (See photos 3 and 4)
Doesn't there have to be a wire that goes direct from the alternator to the battery to charge it? On top of that, when I pulled the makeshift tape wiring harness apart that my lovely car salesman had installed, a lot of the wires were in bad shape. (See Photo 5) Some wires are just twisted together, not even soldered.
I'm thinkin, "where should I start?" I'm gonna put the alternator back in tomorrow, hook my blue & white wire back up to it, and test the alt with a digital voltmeter to see if the blue & white also carries voltage to the battery. Does anyone have a wiring diagram for a 1981 diesel 720 SD22, in case I have to fix the electrician's handy work? Anyone ever had this kind of thing happen?