I'm having some really weird electrical issues. It started when I went out to start the van after not driving it for a couple of weeks. Turned the key to run, glow plugs fired, Wait to Start turned off, no problems yet, everything normal.
Turned the key to start and everything went dead. No engine turnover, no starter turning, not even a solenoid click. I turned everything off and started over. This time when I got to "Run" (before turning to "Start"), my voltmeter on the dash showed weird voltage swings between 0 and 8 volts. A handheld voltmeter on the battery posts showed 12 volts, but the headlights wouldn't work, no accessories worked, auto locks wouldn't work. Meanwhile, the house system is fine.
I tried to jump start the van. No luck. I used a trickle charger. No luck. The van batteries were replaced just over a year ago.
I suspected a short in the starter motor, and my brother has had to replace two starter motors in his van, so I bought a starter motor and installed it. As soon as it was installed, I turned the key to run, and everything was normal. At start the engine turned over but wouldn't start due to low batteries. I charged the batteries with the trickle charger. It started! Problem solved! I drove around for a while. Everything worked except the radio. Okay, will deal with that later.
Got home, parked, idled while I hosed down the driveway (big driveway and lots of dirt from the van). Then parked and turned it off.
Went out the next day to take a drive. The keyless entry worked fine, but the van wouldn't start and was back to weird voltage fluctuations between 0 and 8 volts. After this, the keyless entry no longer worked, and everything was dead in the water. Radio still didn't work. Battery still read 12 volts with nothing on.
I checked all the cables under the hood and there are no obvious worn spots. I bought a battery load tester. I checked the batteries (2 chassis batteries in parallel on the diesel). Still 12 volts, but only 200 cold cranking amps. Okay the batteries are low. I turned the ignition switch to radio - the radio works! So that's not the problem.
I dug into the house electrical system. The house battery is at 11.4 volts, and when on shore power with the breaker on, still on 11.4 volts. Problem with the converter? Checked the converter. Both 30 Amp fuses on the output of the converter are blown. Pulled the fuses. Disconnected the shore power. Disconnected the house battery from the distribution bus. Replaced the fuses. Tried to reconnect the house battery to the distribution bus - arced and blew the two fuses on the converter again. No other loads on the house bus except for the CO sensor on its 3 Amp fuse, and it was fine.
Which brings me to my theory:
BAD CONVERTER. Thus, I can't charge the house battery from shore power, so, when the van is running, the house battery is sucking charge from the chassis batteries and the chassis batteries aren't recharging enough unless I drive for a really long time, which I haven't done.
So, my questions for those of you who know more about electrical than I do:
1. Am I making any sense?
2. Would a bad converter result in this problem?
3. What is the easiest way to isolate the house battery from the chassis batteries?
4. Can I hook up the trickle charger to the 12V positive distribution bus and the ground inside the van to charge the house battery, or will this cause problems? (I'm thinking of charging the house battery, then charging the chassis batteries so that I can get back in business while a source a new converter.)
5. Did I just buy myself a spare starter motor?
Thank you for your help!