1.6A draw on 30A fuse 9 - '77 NYB 400

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Great_White

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Hi y'all,

I found my battery stone dead the other day. Key was off, no doors were open so no lights running, so I slapped in a new battery and started testing for current draw.

After some process-of-elimination pulling fuses, I found that the circuit with the big 30A metal fuse was drawing 1.6A.

Where is a good place to start looking? I'm concerned about disturbing old wiring, especially on an always-on 30A circuit , so I'd like to not mess with too much.

Thanks!
 
A "metal fuse" or a metal "circuit breaker"? What notation was near the fuse in the fuse block, as to what circuit it was?

In thinking about what could be drawing anything on those cars, is there some sort of alarm system on the car, OEM or aftermarket? There is the clock/Chronometer that runs all time. Even if the ar is turned off and all door closed, the dome light door switch or trunk light switch could have failed. Key thing is which circuit is operative. Although there are no FSMs of that model year in www.mymopar.com, the wiring on the 1973s might be similar enough to download and look at the schematics?

Disconnect the battery with the car parked in a very quiet place. After disconnected for several hours or over-night, touch the loose battery cable to its post on the battery. Listen for a faint "dingggg" when you do. IF that happens, the Chime Module has failed. That happened on my '80 Newport. The battery would run down if the car sat for a few days, but no issues if used daily. So when I would park it in my shop, I'd disconnect the battery cable. One night, when I touched the battery cable to the battery post, the shop was dead quiet, and I heard that "dinggggg", then went in search of what could make it. I unplugged the chime module (under the lh frt seat), charged the battery, and left it unplugged (as it was discontinued from Chrysler). Lost all of the key-in-ignition buzzers and such, but no more run-down new batteries either.

Enjoy!
CBODY67
 
CBODY67 said:
A "metal fuse" or a metal "circuit breaker"? What notation was near the fuse in the fuse block, as to what circuit it was?

In thinking about what could be drawing anything on those cars, is there some sort of alarm system on the car, OEM or aftermarket? There is the clock/Chronometer that runs all time. Even if the ar is turned off and all door closed, the dome light door switch or trunk light switch could have failed. Key thing is which circuit is operative. Although there are no FSMs of that model year in www.mymopar.com, the wiring on the 1973s might be similar enough to download and look at the schematics?

Disconnect the battery with the car parked in a very quiet place. After disconnected for several hours or over-night, touch the loose battery cable to its post on the battery. Listen for a faint "dingggg" when you do. IF that happens, the Chime Module has failed. That happened on my '80 Newport. The battery would run down if the car sat for a few days, but no issues if used daily. So when I would park it in my shop, I'd disconnect the battery cable. One night, when I touched the battery cable to the battery post, the shop was dead quiet, and I heard that "dinggggg", then went in search of what could make it. I unplugged the chime module (under the lh frt seat), charged the battery, and left it unplugged (as it was discontinued from Chrysler). Lost all of the key-in-ignition buzzers and such, but no more run-down new batteries either.

Enjoy!
CBODY67
Click to expand...
The chime module? Huh, wouldn't think of that. I'll test that tonight.
Yeah, it is a circuit breaker, not a fuse, it's in cavity 9 of the fuseblock. The owners manual says it's for the seats and windows. I'm looking at my FSM, and I see the wiring diagram for both systems, but I'd like to see what the expected resistance values are for the components to see if anything is wrong before I start tearing stuff apart. I'm afraid of moving stuff around and creating some short that I don't realize until the garage is up in flames some night.
 
I pulled down the fuseblock and found one of the connections for the circuit breaker socket had broken its retaining clip and was no longer connecting to the breaker. I had pulled and reinserted the breaker a couple of times in testing, so who knows if the socket was or wasn't close to failure to begin with. I reseated it and plugged it in so it is firmly connected, and then managed to blow up my cheapo meter when I went to check battery voltage with the meter set to amperage (poof, let the smoke out). The meter does still read voltage, so I reconnected the battery and I'm checking voltage periodically and it's steady as a rock so far. I'll check voltage again in the morning and grab another meter to do another current draw test.
 
Great_White said:
I pulled down the fuseblock and found one of the connections for the circuit breaker socket had broken its retaining clip and was no longer connecting to the breaker. I had pulled and reinserted the breaker a couple of times in testing, so who knows if the socket was or wasn't close to failure to begin with. I reseated it and plugged it in so it is firmly connected, and then managed to blow up my cheapo meter when I went to check battery voltage with the meter set to amperage (poof, let the smoke out). The meter does still read voltage, so I reconnected the battery and I'm checking voltage periodically and it's steady as a rock so far. I'll check voltage again in the morning and grab another meter to do another current draw test.
Click to expand...
Usually, a decent meter will have one or two fuses inside just for that.
 
I picked up a new multimeter and confirmed the draw with key off and all lights out to be in milliamps, so fixing the connection in the fuseblock seems to have done the trick. Incidentally, the meter I popped didn't blow its fuse, but the metal braid that ran between the amp probe socket and the regular probe socket blowed up read good! You can see it on bottom left.

So all's well that ends well, I guess. For my next trick, I gotta pull the instrument bezel to get at the rear window defroster timer relay. It's gotta require less contortion than getting at the fuseblock, right? RIGHT?!? :confused:

1124231051_HDR.jpg
 
I thought I fixed the bugger, but the Dead Batteries (not a punk band) say no... Dove back in with a fresh meter and a chastened attitude. I'm getting 800mA draw on fuse 6, and 1A draw on the circuit breaker in slot 9. This was measured with an DMM in the 10A range inline between the negative battery post and negative cable. I disconnected the 3 electrical connections under the carpet on the drivers side, no change on the draw. I also tested voltage drop over the fuses, these circuits are the only ones with any notable readings.

Slot 6 is a bunch of things, so I guess I'm pulling the dash bezel next, unless y'all have another approach. As for the breaker in slot 9, the only other thing on it to my understanding is the power windows and maybe the locks? Is there a way to test the circuits and/or components with a ohmmeter?

mark_knife.jpg
 
Great_White said:
I thought I fixed the bugger, but the Dead Batteries (not a punk band) say no... Dove back in with a fresh meter and a chastened attitude. I'm getting 800mA draw on fuse 6, and 1A draw on the circuit breaker in slot 9. This was measured with an DMM in the 10A range inline between the negative battery post and negative cable. I disconnected the 3 electrical connections under the carpet on the drivers side, no change on the draw. I also tested voltage drop over the fuses, these circuits are the only ones with any notable readings.

Slot 6 is a bunch of things, so I guess I'm pulling the dash bezel next, unless y'all have another approach. As for the breaker in slot 9, the only other thing on it to my understanding is the power windows and maybe the locks? Is there a way to test the circuits and/or components with a ohmmeter?

View attachment 631547
Click to expand...
You could measure the resistance of a circuit. Tracing your situation is going to require a LOT of patience!
 
Some of those electrical draws are hard to find. Diligence is your friend here. I once had a small draw like that ended up to be the damn light in the glove box. Switch failed to turn off the light when the glove box was closed. I found it by accident when I went out at after dark and spotted a glow under the dash that shouldn't have been there. Good luck tracking it down.
You need a wiring diagram to see what slot 9 feeds. How about a trunk light that is not shutting off?
 
Last edited:
Sixpactogo said:
Some of those electrical draws are hard to find. Diligence is your friend here. I once had a small draw like that ended up to be the damn light in the glove box. Switch failed to turn off the light when the glove box was closed. I found it by accident when I went out at after dark and spotted a glow under the dash that shouldn't have been there. Good luck tracking it down.
Click to expand...
I had a similar problem on my 65 Ranchero.
 
Son of a...

So I picked up an amp clamp and a battery charger and dove back in... Got the battery fully charged and started looking for clues, but before i tried tearing the dash apart I thought I'd try a hail-Mary, so I closed the garage door and turned off the lights, checking to see if I'd missed a glovebox light dimly lit or something. Sure enough, I saw the light on the driver side C-pillar was lit, key off and all doors closed! Tested all the doors and trunk to see that all the other lights operated normally, but this one remained on when everything was buttoned up. Took the trim panel off, pulled the bulb, and 48 hours later the battery hasn't budged. Turns out the only dim bulb was me!

Patience paid off. Now on to the half-dozen other things that have been put off until I got this figured out...

received_230752060052549.jpeg
 
I don't think it's a switch, at least not a door switch, because they work properly and all the other interior lights go on and off as the switches open and close. The trunk light switch, glovebox light switch and map light switch all work as expected. The one rear C-pillar light remains on 24/7 regardless of key or door position. If removing the bulb fixes the draw, I'm fine with that. I've been chasing electrical stuff for quite a while now and need to move on to other matters.

For example, I don't have a title yet because the state of North Cackalacky requires me to get a safety inspection first (?). Before I can do that, I need the front end gone over and aligned. I finally found a shop to do the work, but had to cancel because the battery kept dying.
 
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