I had an interesting issue this morning on my way to work. I was driving and noticed my floor lights were on. Dome light off. Flipped the dome light on and off no change. Pulled up to a light and opened the door and the floor lights turned off and the dome light came on as normal. When I got to work I had to pull the bulbs to keep the battery from draining.

It seems like a reverse polarity issue, but not sure what caused it. Wasn't like that when I parked the car last night that I know of. I would think I would have come out to a dead battery this morning. Anyone else run into this issue?

fuse is blown
See my Cave, Sneak Path

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

I agree with the Ogre. Check your fuses.

Thank you Ogre. Just got home from work and checked. The culprit....blown BATT fuse. I'm off to the parts store for a fuse and some extras for the extra fuse bank. Only had one 5 amp fuse in there. My radio has been flaky too. Wonder if that has anything to do with it.

I believe it's 20 amp.

quote Originally posted by Blacktree: I believe it's 20 amp.

Ok thanks. The fuse may have blown for a reason...don't want to put a larger fuse in there and fry something.

Update: according to the repair manual, it's a 20 amp fuse that powers the dome lamps, horn relay, radio clock, and cigarette lighter. If the fuse blows again, I'd check the horn relay and the cig lighter. They're the most likely culprits.

Wow. Went to plug in the fuse and it had a small arc. Tried again and the arc was larger. I stopped there......

Like I said before, the radio was flaky and appeared that it didn't have power for a couple weeks. No light issue though until this morning. After the arc the radio clock turned on but radio doesn't work. could the radio be flaking the circuit?

Check for a coin in the cigarette lighter socket. Take it out and unplug it and see if the trouble clears.



That or the horn or the radio, but my guess is the coin in the lighter socket.

[This message has been edited by phonedawgz (edited 09-19-2016).]

quote Originally posted by phonedawgz: Check for a coin in the cigarette lighter socket. Take it out and unplug it and see if the trouble clears. That or the horn or the radio, but my guess is the coin in the lighter socket.

Thanks Phonedawgs. No coin in the socket. Checked that already. Why such a big arc when trying to replace the fuse?

One of those items is shorting to ground. Don't try a bigger fuse. Unplug the items that are shown on to be powered by the fuse and see which one stops the fuse blowing. If you didn't yet unplug the cig lighter that would be the first for me. It's easy to get to and still seems most likely even without the coin.

Any chance the Orange wire that connects to the lighter circuit is not on it and has fallen onto a screw and is shorting to ground?

Since the radio is still doing something I would put that low on the list. But unplugging the radio will eliminate it from the circuit/

Any chance there has been damage to the wiring harness? If you haven't seen it, consider it fairly unlikely.

To eliminate the horn from the circuit unplug the horn relay




While it takes a few fuses, troubleshooting a direct short is much easier to do than troubleshooting a poor short to ground or an intermittent one.

[This message has been edited by phonedawgz (edited 09-19-2016).]

Lighter socket can have other problems blowing Batt fuse.
Unplug the socket.
See my Cave, Lighter

Batt circuit is memory power to radio. GM Radios often won't turn on w/o this but won't normally blow any fuse when radio is bad.

Could be a jam switch broke (front of door frame) and allow wire(s) to short to frame.

Horn switch etc can short out too.
Unplug relay then steering column to quick test

[This message has been edited by theogre (edited 09-19-2016).]

The trunk light is also on the same fuse as the courtesy lights. (At least mine is, but mine was added later. Didn't come with it.)

quote Originally posted by Raydar: The trunk light is also on the same fuse as the courtesy lights. (At least mine is, but mine was added later. Didn't come with it.)

My trunk light is functional but no bulb. I pop the hoods at shows and want to avoid the battery drain. I also have the front trunk light too. I should replace the bulb in that one though, or have one on hand. Could come in handy.

Issue is resolved. I disconnected the neg battery cable, plugged in the 20 amp fuse. Reconnected and all systems are normal.

Now to replace those floor lamps with red LEDs.

quote Originally posted by Jason88Notchie: Issue is resolved. I disconnected the neg battery cable, plugged in the 20 amp fuse. Reconnected and all systems are normal.

Likely the battery will die because have too much power draw w/ key off.
Nothing should draw enough power to spark on Batt fuse.
Iffy lighter and/or socket can be big problems or even start a fire.

quote Originally posted by theogre: Likely the battery will die because have too much power draw w/ key off. Nothing should draw enough power to spark on Batt fuse. Iffy lighter and/or socket can be big problems or even start a fire.

Wouldn't the fuse hopefully blow before that happens?

I had my cell phone charging off the lighter for a good part of the day before I recognized the issue the next morning. The charger plug did get pretty warm to the touch when I unplugged it. Do you think the power draw from the phone over that period of time may have blown the fuse?

[This message has been edited by Jason88Notchie (edited 09-22-2016).]

quote Originally posted by Jason88Notchie: Wouldn't the fuse hopefully blow before that happens? I had my cell phone charging off the lighter for a good part of the day before I recognized the issue the next morning. The charger plug did get pretty warm to the touch when I unplugged it. Do you think the power draw from the phone over that period of time may have blown the fuse?

No.

Not by itself. All USB car chargers get warm to hot because they just regulate 12-15v down to 5v 1a to close to 3a max.

[This message has been edited by theogre (edited 09-23-2016).]

quote Originally posted by theogre: [QUOTE]Originally posted by Jason88Notchie: Wouldn't the fuse hopefully blow before that happens? I had my cell phone charging off the lighter for a good part of the day before I recognized the issue the next morning. The charger plug did get pretty warm to the touch when I unplugged it. Do you think the power draw from the phone over that period of time may have blown the fuse?

No.

Not by itself. All USB car chargers get warm to hot because they just regulate 12-15v down to 5v 1a to close to 3a max.

[/QUOTE]

Ok. Thank you Ogre. I'll keep a close eye on it and dig into it over the weekend.
[/QUOTE]

[This message has been edited by Jason88Notchie (edited 09-23-2016).]