Chasis shorted to positive

[solardude]

Hard to know where to start. I am a certified electrician/ licensed electrical contractor with 45 years experience in residential, commercial and industrial new construction and service. I was installing the "new" cassette tape players in my neighbors cars in the 70's when I was 16. I have owned a few boats and have done extensive wiring on 12vdc systems. I have worked with grid tied solar systems for the past 6-8 years. 3 years ago I bought an older conversion van and turned it into a camper, I put a 300 watt solar system of my own design on it and it has not failed to perform to this day. I honestly think I know what I am doing, however I am NOT and never have claimed to be an "automotive electrician"
So the issue is that I took pity on a 70 year old neighbor who could no longer afford rent, bought an Astro and is going nomad. I have had (2) Astros myself as work trucks. I installed a Renology 200 watt "kit" solar system with two Interstate GC2 batteries (as I used on my own van) for her at no charge for labor and since she was short the cost I added $200 of my own money to the 20 hours of work I volunteered. A few weeks later electrical problems developed in the van, the door locks are not working. Now both the owner and her mechanic are saying it's all my fault, "my" solar system is energizing the chasis. I tried to explain that the the solar system is isolated and not in any way connected to the van but she has no clue and he does not speak English and is probably embarrassed that he cannot find the problem. Easier to blame it on the solar installation that he does not understand. He thinks that when I attached the panels to the roof using the provided screws I tagged a wire to a dome light or something. Okay, reasonable and possible. My thought is to pull fuses one by one until the problem goes away, does that seem reasonable? Obviously something is shorted to ground.

[N6KB]

With your resume' I don't understand why you are asking this question. Yeah you could either remove fuses one by one until the problem goes away, or remove them all and put them back in one by one until the problem reappears. Of course whether either of these methods will work sort of depends on whether the problem is there without the ignition switch on and the engine running. It will be much easier to find if the problem is there all the time without the ignition on and the engine running, because if you first remove all of the fuses you're not going to get the engine started. I prefer removing all the fuses first and putting them back in one at a time while you are monitoring battery current with your DMM. As soon as you put in a fuse that causes current draw you need to determine if it is feeding a proper load or a fault load.

[Rod's Trucks]

A 'short to the chassis' would blow a fuse or burn out a wire if it was improperly fused, so I would first look for a blown fuse ( both fuse panels).
It is also quite possible that the door lock failure is not at all related to your installation, and that it is just a random, poorly timed and somewhat common, failure. But, you were the unlucky 'last person to have worked on the van' so it is easy for an incompetent mechanic to blame you.
The Central Locking System gets quite a bit of ink here.

Do none of the locks work? Just some? Key on or Key off?
Any other clues or other things that do not work?
You will need a wiring diagram that shows the circuitry and fuses in detail, but with your background that diagram should be able to lead you to determine what has failed.
Rod J

[97cargocrawler]

Look for a cable coming off the starter that could be rubbing on or near the motor mount. I had a short to chassis there once.

[AstroWill]

There isn't a lot of wiring up there, pulling the fuses for the dome lights would exclude you from the problem.

Not sure if you are going to help diagnose the issue or not, but I would get a more detailed description of what is happening if you are going to move forward with it. Just be careful, because you could create more of a liability for yourself.

[sixsix]

... My thought is to pull fuses one by one until the problem goes away, does that seem reasonable?

With your resume' I don't understand why you are asking this question. ...

Haha... was thinking the same thing at first too.
Then I pondered...