Technical Need some electrical hints.

I went to a chiropractor years ago that used an infrared camera to shoot pictures of me. The result showed hot spots where I had alignment issues that he could address. Pretty sensitive camera that he filled with liquid nitrogen, weird science stuff. But it does make me wonder, in today's electronic marvel world, if a camera could take a picture of a car and identify the heat signature of a short or draw. Sure would save time fussing about.

 

Good advice here. Do you have a schematic from Painless that you're working from? If so than make sure that each of the circuits that your trace out match the schematic, and if they don't, correct it, one at a time. If you don't have a schematic, then start drawing one as you trace out each circuit.

I didn't wire my 30 pickup, it was already wired up and a driving vehicle when I acquired it. It doesn't looks like a commercial wiring kit was used, just some guy with a ball of wire and some wire cutters and crimpers. Behind the dash is a rats nest of wires. I know that one of these days I'm going to have to drag it all out and redo it all, I'm just putting it off for now cause it works; but I know what really needs to be done, just haven't talked myself into doing it yet.

 

Well, my advice has already been given. Most of the time when I encounter a vehicle that drains the battery over a period of time, I find the problem in the alternator. I actually have one doing that now….so I just unhook the battery cable, as I rarely drive it and the battery will last several days! But yours draining the battery in 8 hours is a fairly large drain, or you have a comprised battery.

Do the light bulb thing and eliminate each circuit, one at a time. As has already been mentioned. This is the path to the solution! Plus you might want to have the capacity of your battery tested or substitute a known good battery.



Bones

 

Guys have been using infrared cameras to do this for quite a while. I've seen some comments that doesn't always work and isn't necessarily faster than old fashioned circuit tracing. It does seem like it would at least point you in a direction.

 

Used "thermal cameras" to uncover the heat signature on the circuit boards of several electronics products over the years.

 

Someday I am going to catch one of those electrical gremlins and see what the little bugger looks like! SOMEDAY!

Ben

 

If you have a multimeter, when everything is turned off and fuses are removed, disconnect the negative battery cable and then measure current between the cable and battery. It gives you a better idea of just how big the current draw is, compared to using a test light. On a modern car there's always going to be a few milliamps because of computers, digital clocks, etc. but on a HAMB friendly car the current draw should be zero or close to it.

Just to eliminate it as the problem, make sure you don't have a bum battery that's self discharging overnight. Swap in a known good battery, or take it to the local auto parts store and have it tested.

Also, assuming you have an alternator make sure it's not defective. If the internal diode pack fails, there can be a continuous current draw. Finally, make sure the previous owner didn't make some basic error when he installed the new wiring. I remember when I was a kid I tried to convert my car from a generator to an alternator, and while it charged normally when the engine was running I made some mistake that would drain the battery overnight.

 

Hmmmm. I've actually used one of those thermal cameras at my old workplace. Found which of three, three-phase lugs in a high current contactor was causing an issue.
The above mention of it does have merit. One could trace ANY warm or hot spot in real time, to find a heat signature. Remember, ANY current flow, whether it be in a wire, or through an electrical load, will also cause a heat signature that can be found.

The issue is that those cameras are not a low-budget item.

Roger

 

What I use is one of the old Ford or GM seat belt buzzers. Connect between the battery cable and the post. Any draw will make it buzz. This has the effect of letting you know when you have fixed it while anywhere in the garage and it's annoying so you work fast!
As said, if this is happening while the key is off, concentrate on the circuits that are unswitched. Horn, lights (brake switch is common), power to ignition. Anything that works with ignition off. This depends on how it was wired, but just try everything and write down what's constant.
Stuff that is switched can all be removed/disconnected at the ignition feed.They shouldn't be a drain if not powered.

They made different tools to do this job. One used a auto resetting circuit breaker to kick on and off power. You also got a small gauge that would react to the power going through the wire, so you could move it along the circuit and see when the on/off signal stopped.
They also have non-contact ammeters but you need to be able to have them surround the harness/wire.

 

Well, it's been a while. I gave up and walked away from it for a while. I have plenty of other crap that had to be done. Today I dug in again. It didn't go well. I decided to pull the light switch and wiper switch to check the wiring. The light switch is always hot so I thought there might be a drain there. Nothing. I put everything back together and the short seems to be gone. All I did was move some wires around, including the Vintage Air controls. I couldn't find anything rubbing on a sharp edge. I hate to see it end this way because I didn't fix a damn thing. All I can do now is wait to see if it comes back. For all the guys who suggested the alternator, it shows a very slight draw when connected. It's not enough to light the bulb and my test probe indicates that it's under three volts. I'm going to try disconnected for a while then connected to see if it makes a difference. Thanks to everyone for the suggestions.

 

I'm quite suspicious of things that suddenly fix themselves .

 

Absolutely