docmirror

Okay, sounds like you've got the bases covered. I just want to reiterate that electrical diagnosis and troubleshooting is a distinct field of study from the usual cams, carbs, cranks type of repair. The tools are different, the approach is different, and the emprical evidence is not usually as clear as with mechanical components. This gets many, many mechanics in over their head.

Best of luck, hope they find it(them) without too much time.

Doc

Dennis Wilson

Fuse 15 is the power antenna. Try pulling the power connection at the antenna. Fuse 23 is for your interior lights. This includes the light above the mirror, in the glove box and in the hatch. A couple common break areas are at the door switchs and the connections at the back of the light assemblys. Since these use battery power (circuit 30) any short would cause a constant drain. Try pulling the lights and switches and look for loose or frayed wires that could be contacting the body.

Dennis

bronto

I can tell this is going to get real frustrating

I decided to give it one more shot before taking it to the shop, this time getting a better multimeter and disconnecting all 3rd party accessories I could. Not a real expensive multimeter, but at least this one is digital and has an unfused 10 amp option so I could at least see how high the draw is.

First goal was go get a baseline reading before doing anything else. Huh. 1.5 amps. And the door was open with the dome light on. Shut the door, light goes off, draw is .15 amps. This seems "right" to me (doesn't it?). So I'm thinking that maybe pulling a relay caused it to close. Pretty hard finding a problem where there are no symptoms.

I tried hooking everything back up and starting the engine to see if anything would "stick" again. Started no problem, turned on lights, turned off lights turned off motor (about 2 minutes running in all). Retested circuit with same readings as above. HOWEVER, with the engine running, there was a sort of buzzing sound coming from the fuse panel area. More evidence of a bad relay? Really couldn't tell which one it was. Or maybe it's always been like that, but inaudible when the panel is covered...

So it seems that this may be an intermitant problem.

BTW, I also hooked up my bulb only circuit tester to see how brightly it shines, and it's the same brightness as before. So the high current may have disappeared several days ago for all I know.

Alan

Bronto - 0.15A is still not good thats 150mA - you still have a problem - you need to be looking for ideally 0.015A - 15mA or maybe up to 50mA but 150mA is too high - that is about the current taken by a relay coil tha is staying on for example.

It won't discharge your battery overnight but it will in a week or so if you drive infrequently...

Alan

bronto

OK, I guess I was a decimal place off of "normal". I'll try it again tomorrow.

F4GIB

You may find a trickle charger much "cheaper" in terms of hours and frustration. Jusy pull the car in the garage and plug it in each evening.

SharkSkin

Your circuit tester must have a low-wattage bulb. I think mine is a 5W bulb, which would have glowed very dimly at 150mA. Also, did you have any doors open or interior lights on while testing? That would show enough draw to light the tester.

One other thing -- I thought we had covered this, but there have been a few threads on this subject recently and glancing back at the posts I don't think we did: When you have had the car running and shut it down for the test, make sure that you *always* have the ground connected in the system.

In practical terms, this means connect your ammeter to ground, and to the ground cable before you disconnect the ground cable. This way you never interrupt power to the system. Sometimes a relay will remain latched and causing a power drain after you shut down, then unlatch when you disconnect the ground strap. Then when you connect up the meter, you won't see that drain on the system.

I've been bitten by this, found a different load when setting up this way, and had to go through the whole set of fuses all over again. Just ask Ron, Bill or Konstantin.

bronto

Darn it. Back to the drawing board.

SharkSkin

Sorry... I thought that I mentioned that in a similar thread recently, I was just mixed up as to which one. If you see the same current draw when hooking up this way, then there's no need to start over.

docmirror

Yep, I forgot to mention that too. It's ingrained in me to do it that way, but didn't bring it up. Wehn you are looking at the meter, be sure to get the decimals right. You could be reading "15x." or "15.x" and be off by a factor of ten. Usually, the meter will have a separate plug for the 10amp range. Make sure yuo are NOT in that range when you start the test.

So, gain access to the batt. Close door, start engine, stop engine, leave doors closed. Wait a few minutes, connect negative lead to negative batt terminal, connect positive lead to ground cable. Now remove the ground cable from the batt without interrupting the meter circuit.

Check current draw. Have helper watch meter and record as you pull fuses, then relays. Watch for changes on each pull. Isolate from the circuit when a reduction happens.
Doc

bronto

Why would I not want to be in that range? My last multimeter was limited to 200ma and blew fuses in the meter. When the dome lights are on, it draws 1.5 amps, which (if I've got my decimals right) comes out to 150 miliamps. If there's a higher spike than that at any time, I think I've got another blown meter fuse. (I find it odd, BTW, that the shops that sell meters don't have replacement fuses for them. Radioshack?) I really thought I bought the new meter so that I could use that circuit. I know it's dangerous to use an unfused circuit, but it seemed necessary here.

the flyin' scotsman

150 milliamps = 0.15 amps

You use the unfused circuit of the meter at the risk of destroying it.

bronto

"destroying it" = the meter? That's what I thought, and am prepared to sacrifice a $20 meter.

the flyin' scotsman

Yes, the meter................it should have different positions for the positive lead to handle the higher current.

docmirror

Well, if you are on the 10 amp range, you won't see much resolution when the changes are in the 150-15mA. The meter will only show 10.00 amps. So, on the 200mA range you can measure up to 200mA. That's why I said to close the door, and leave it closed. If you want to start on the ten amp range to insure you are below 200mA that's fine, but then you have to start the test all over again with the meter in the 200mA plug.

When you get fuses for the meter, get 5 of them, and be prepared to blow a few. This is what I was saying about using the right tools, and it being a challenge. If you had a 2 amp range on the meter that would be ideal, but we work with what we have. So, stay inside the car, don't open the doors, connect the meter, and check the load. Work your way down the fuses then the relays.

Doc