Battery Drained and Blown Fuse ...

[Duffman]

OK, my battery needed to be recharged as it died on me after 10 days or so of non use. I recharged the battery (w/charger) and noticed my 10 amp "Dome and Gauge Light" fuse was blown. I put a new fuse in and it blew as well, with the car turned off. Now, I shouldn't have any draw on that fuse with the car off, so I am confused. I hooked up a multimeter and noticed a draw of about 50 amps going thru the fuse terminals. I also checked the battery with the car off and noticed about the same draw on the battery, with the blown fuse out. A short somewhere? Any ideas of where to look? I just installed a new stereo, but the connections are not part of that fuse. I disconnected the stereo just to make sure and no difference.

[Duffman]

Any thoughts? I am thinking ground or a misconnection somewhere. What makes this weird is that the fuse for the instrument panel/dome light blows when the car is not turned on. Still checking around my connections, open to any ideas.

Help!!:eek:

[EScanlon]

The dome light wiring is always live.... ignition on or off. Sounds as though you have one of the wires at the door pillars or at the connections (at the extreme ends of the dash) making ground.

Since you just installed the stereo, are you sure you didn't tap into the dash light circuitry with the radio's wiring?

FWIW

E

[Duffman]

Thanks, E, I appreciate your response. I will follow up on both ideas. Since the fuse is blowing with the ignition off, it may be the wires at the door pillars grounding out. Will let you know!

[Arne]

So that's the fuse that has the red/blue wire on the output side? If so, it supplies the key buzzer, map light, glove box light, dome light and step lights (if you had them) on it's way to the combo switch. I'd start by systematically disconnecting those items and their switches (if separate) one by one.

The amount of current being drawn (50 amps!) makes me think there's a dead short somewhere in that circuit. My first step would be to disconnect the combo switch.

[Duffman]

Thanks, Arne, good idea. I just cleaned up the signal switch a few weeks ago and may have reconnected something incorrectly.

[EScanlon]

My prior comment may be more misleading than helpful.

If one of the wires going to the switches at the door, or at the dome lamp makes contact with the body metal, i.e. grounds itself, it will complete the circuit for the dome lamp. That will drain the battery within a short period of time. However, I doubt that it would blow the fuse.

A 50 amp draw? That's a major draw... more like what I would expect a starter or the headlights (combined) to draw.

Once again, I would check the radio installation as that seems to be the common item.

E

[Duffman]

OK, finally have a chance to work on this problem. I believe I have a positive lead connected to a negative lead somewhere in my system. As I have said before, my Dash Light fuse (10 amp) blows. Checking the draw on the fuse terminals shows me 12.5 volts, which is identical to my battery current. I checked the reading between my - battery terminal and the cable and also came up with 12.5 volts. So, even with my fuse blown and disconnected, I am still getting a 12.5 volt reading off my negative battery terminal. I am thinking I am creating a circuit that is constant even with the fuse blown.

I have disconnected my stereo, my combo switch and A/C, to no avail. Am thinking I have some ground wire that is connected to a positive lead. Would that cause the problem? Am I way off on this? Any other thoughts?

[Duffman]

As I am thinking about this, I cannot understand the high current reflected off of the negative battery terminal if the fuse is blown. I shouldn't be getting the draw with a blown fuse, or I should have other blown fuses. Therefore, I must have something directly off of the battery that is connected through the blown fuse. With that in mind, will look at battery connections and see if something is amiss. Any other thoughts, throw them my way!!!

[EScanlon]

Stephen;

I'm confused by your comment that in checking the "draw" you are reading 12.5 VOLTS at the fuse box. Yet to my understanding what you are measuring is 12.5 volts of potential at the fuse box and not the DRAW, which should be in AMPS.

So, do the following.

Get a 1156 bulb (single filament lamp) and insert it into the battery wire clamp of the negative cable. Insert it such that it won't slip out or through. Next, lay the bottom solder ball of the bulb onto the negative pole of the battery. If the bulb glows.... you have a current flowing; no glow, either no current or so small as to not be the cause of your discharge. (Although over time it CAN deplete it.)

Now, with the bulb aglow, start disconnecting fuses. When the glow disappears, you have found the circuit that's causing the draw. That's where you begin. Now, if you haven't got a glowing bulb, insert the Dome Lamp fuse and see how bright the bulb then glows.

Checking the value of the current draw (by connecting your multi-meter inline with the battery cables) is helpful only in knowing that you have a High or a Low current draw.

FWIW

E

[Duffman]

Thanks, E, I am a neophyte electrician, as you can tell. I am reading the wrong gauge, will focus on the amperage.

Is it normal to have a full 12+ voltage reading between my negative pole and cable? I can understand that it would read that between the + and - poles. I believe that something is wrong as I get that voltage even with the blown fuse missing! It is confusing to me ...

[Duffman]

Ok, I was under the assumption that the "Dome Light" fuse also covered the gauge lights, am I wrong? The reason I ask is that when I connect the battery, with the Dome Light fuse blown, the gauge lights all work when I turn on the headlights. But the clock does not work, which it did before. What a brain twister!!