MattK

88 Max wagon with 172K. With the ingnition off I still have continuity between the (-) term and ground strap so I guess I have a short curcuit. A simple bulb tester blows as soon as I connect it but using a mutltimeter I can monitor continuity. I removed each fuse one by one and none of them broke the continuity. I diconnected the alternator as suggested by HAYNES but that didn't do it. BTW the alt was not charging as well as it should so I replaced it with a good spare I had and now I have a steady 15V charge that does does drop with accessories on etc( the oldone was hovering around 12-13 lately. I am wondering if perhaps I always had this problem and it showed up now because the ALT died.

ANy thoughts on where to look beyond the fused circuits? I am guessing that if the short occurred before the fuse then fuse removal would do nothing.

thanks for any help

MattK

blackmaxima88

WAIT!!!!!! STOP!!!!!

DON'T use a continuity tester to make this test! that is why you keep burning them out! Use a 12-volt circuit tester. a continuity tester has its own internal power, a battery, for continuity checks, they're useful for fuses, switches, etc.

a 12-volt circuit tester is different. it's simply a light bulb that can withstand automotive voltage (usually up to 28 volts). THIS is what you want to use!

if you're using a multimeter, make sure you are using a DC VOLTS scale. also note that any ammeter function gets connected differently than a voltmeter. an ohmmeter has no purpose in this test.

here's the procedure:

(1) start with a fully charged battery.
(2) disconnect the negative battery cable from the post.
(3) connect one end of the circuit tester to the end of the battery cable, touch the other end to the negative battery post. so now, essentially, that tester is connected between the battery and the cable.

if the tester lights, there is a drain. NOW you can pull the fuses, disconnect the alternator, etc.

also try this, it just came to mind: disconnect the positive battery cable from the solenoid terminal on the starter. perhaps there may be a bad winding in the solenoid. not likely, because it's controlled by the ignition switch, but possible.

only other thing I can think of... possibly..... on your positive battery cable, at the battery terminal end, there should be a few plugs and disconnects. these are for the ignition, etc., anything that receives +12v from the battery other than the starter/solenoid. maybe you can try disconnecting these and running the checks again.

you can also check the fusable links, they're in a little plastic case next to the battery, about 1" wide and 3-4" long. I think there are 4 of them, the cover has a diagram. the first one should say "ALT. NAT. BATTERY", another one should say "Power Sunroof", and I think another one says "IGNITION"....but I'm not positive. I'm not so sure how helpful these are.

voltage across the battery terminals on a good alternator is generally 13-15 volts with the engine running at idle. on a dashboard voltmeter, like our maximas have, the needle should remain to the right of the 12 mark. on a dashboard ammeter, the needle should indicate charge, marked by "CHARGE", "C", or "+".

with the engine off, connect the voltmeter to the battery terminals. you should read about 12.5-13.5 volts, give or take. then turn the ignition switch to "ON" without cranking the engine. make sure the charge warning light ("battery light") on the dashboard comes on. if this light does not come on, it indicates either a burned out bulb, loose plug, or bad alternator. there is a 2-terminal plug on the alternator, the thin white wire goes to the charge warning light. the other is the field circuit from the ignition. this plug needs to be in completely for the alternator to create a magnetic field to be induced by the stator coils (work). if there's an internal malfunction in the alternator, -12v is sent to the charge warning light, causing it to light up.

now start the engine. make sure the charge warning light goes out. the dashboard voltmeter should be to the right of the 12 mark, and the voltmeter at the battery should be anywhere between 13.0 and 15.0 volts. any less will undercharge your battery, eventually draining it and condemning it to a shorter life. any more than 15.0 volts will overcharge the battery, causing it to heat up, gas violently, lose water, and start spewing battery acid. that's in addition to causing lights to burn out.

how old is the battery? it may be in your favor to check. a battery at or near the end of its life will simply lose power from sitting.
a battery that is well maintained and kept charged should last at least 6-7 years. a battery that is installed and then ignored will only last a few years. with more summer driving, the fan and a/c are used more. even when the engine is running, this puts a strain on the battery, cos the alternator doesn't have time to fully charge it.

with the engine off, take the caps off the battery (if you can) and look in the cells and check the fluid level. it must be at least above the lead plates. most batteries have a small split-ring tube that indicates proper fluid level. if it's low, get yourself some DISTILLED WATER and slowly add some to each cell until it's at the right level. this is because the water in the battery acid evaporates. heat speeds that process up.

you might also want to have the battery load-tested, most auto parts stores do this free of charge. this determines the battery's ability to supply the CCAs needed to start the engine.

if the battery needs to be charged, use a charger with a relatively low rate. using a high-amperage charger puts a lot of strain on the battery. a good rule is to go 1/10th of the amp-hours but batteries are no longer rated in amp-hours. a 6-amp charger is good, but I wouldn't go any higher than 10 amps.

also keep in mind that using an alternator to charge a dead battery (as in jump-starting) is a lot of wear and tear on the alternator. it's ok in an emergency but I wouldn't make a habit of it. a dead battery in a vehicle will pull more current than the alternator can supply, in most cases, causing the alternator to get hot, causing premature failure.

I know there is a lot of information here that I just wrote, I hope at least some of it helps you.

blackmaxima88

and one more thing: chances are your problem is not a "short". if there was a short, believe me you'd know about it. a short is (in this case) positive touching negative with no load, no resistance between them. this would do a lot of damage really fast. it'd create a lot of heat, burn the insulation off the wire, causing smoke, and make a really bad smell. then either you'd blow a fuse or a fusable link, or the main fusable link. yes, there is a main fusable link. automotive electrical systems aren't vulnerable. shorts don't linger around. if there is no fuse, whatever wire was shorted would get red-hot and start a fire within seconds, almost guaranteed.

I take it this isn't the problem.

this happened to me one time in my VW Fox, the positive battery cable touched the exhaust manifold and shorted the battery. I put my flashers on, the wiring for them was melted and instantly caught fire. I felt like a moron driving that car to begin with, I felt even dumber standing on the side of the road spraying a fire extingusher under the hood.

so you probably have a drain, something that is actually using that power. these maximas have features that use battery power even when the ignition isn't on.... for example, the power seats, or radio memory, headlights, trunk lamp, hazard flashers, security system, the list goes on.

but just try the test with a 12-volt tester this time (not a continuity tester) and let us know where you end up. I'm sorry to tell you there is no simple or quick solution to these problems.

Good luck and I hope I've been of some help!

Dan

MattK

Thanks for all the great info Dan and the effort you put into the post. Using the multimeter I do get 12V across the battery. Also the battery is new and now the alternator is vritually new. The system is chrging better now.
This all started with a dead battery that was fairly old so I knew it was time to replace. Then 2 days later the new battery was dead.

You are right that if this was a short to ground something would be fried which is not the case. I did go through most of the fusible links. removal of them did not break continuity I disconnected the front drivers seat motor with no luck. I will try the starter as you suggested and I think I will go through all the basic systems and check each powered item one by one.

it is frustrating that removing fuses won't allow me to isolate it.

Matt

blackmaxima88

yeah there's no quick or simple solution to a battery drain problem, sorry to tell you, it usually takes a while to figure it out.

another thing that receives power when the ignition is off is the factory alarm system. I have a sedan, and the control unit for it is in the trunk. since you have a wagon, it's probably in a different spot. I can look it up in the factory service manual and let you know where it is. all you need to do is unplug it. see if that doesn't help.

MattK

Thanks Dan

I do know where it is int he trunk are of the wagon. I'll try it

thanks

matt

86Wagon

You will have continuity between between the (-) battery
terminal and the ground strap.

This is normal... the ground strap makes sure the engine/
body/frame are all at the same ground potential.

If you have a short or a "leak", something is either across
the (+) terminal and ground, or you might have a bad ground
somewhere causing the circuit to "float" above ground.

Scott

MattK

[QUOTE]Originally posted by 86Wagon
[B]

You will have continuity between between the (-) battery
terminal and the ground strap.

This is normal... the ground strap makes sure the engine/
body/frame are all at the same ground potential.

I definitely see what your saying but why does Haynes suggest trouble shooting the problem this way? or Should I be looking for a 12V draw with the ignition off?

I beleive the new alternator has soved the problem. I guess the one with 172K although charging jus wasn't able to keep up with the summer demands of A/C etc.

matt

blackmaxima88

(1) look for a 12v draw with the ignition and all electrical accessories OFF, doors and tailgate closed, etc. connect the 12v test light between the battery's (-) post and the battery cable. this is a simple "series" circuit and the lamp inside the test light uses so little current that any "leak" will cause it to glow.

(2) summer and winter are the hardest on your battery, in the summer people tend to make more shorter trips, therefore the alternator doesn't have a chance to fully charge the battery. in addition, the A/C demands more power from the engine, causing the alternator to work harder to keep up. the a/c compressor is what turns the alternator. alternators have a variable field that causes them to demand more mechanical power (rotation from the engine) if the output current is high. older cars with generators (pre-70s) do not have this.

in the winter, generally people will use the heater, defogger, headlights, etc., thus taking away some battery power. not only that, cold weather decreases a battery's starting power. I don't know what the max output current is from our alternators but it's very easy to draw 30 or 40 amps. what the alternator can't handle must come from the battery.

keeping a battery charged on occasion with a charger, especially in the winter, is a great idea and the battery will last considerably longer. like the rest of the car, the battery needs maintenance too.

blackmaxima88

I was wrong, a generator field can do the same...I think...not positive though, depends if it has a fixed magnet or electromagnet. I've disassembled and rebuilt alternators, but no generators....

although it's irrelevant to your problem. it's just there to show how summer and winter demands are typically harder on the battery.

Sorry. to make a long story short, yes, summer can cause that....