Help - Alternator - Electrical smell
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Laughing Gas
Joined: Oct 2003
Posts: 967
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From: DC
Help - Alternator - Electrical smell
I replaced the alternator last night based on the following problem:
Battery light on with RPM below 800 or above 2000. Voltmeter was steady in the middle of the range.
Went for a test drive with my new (rebuilt) alternator. Worked fine for about 10 min, then battery light came on steady, volt meter pegged at 18v and headlights got much brighter. I figured the regulator died, so I got another alternator.
I replaced the alternator again. Ran the truck for about 5 min and started to smell electrical burning smell. So, I shut down and looked at wires and fuses. Nothing obvious. Any ideas? I'm posting this in the electric section too (I want to fix it tonite). Thanks.
Battery light on with RPM below 800 or above 2000. Voltmeter was steady in the middle of the range.
Went for a test drive with my new (rebuilt) alternator. Worked fine for about 10 min, then battery light came on steady, volt meter pegged at 18v and headlights got much brighter. I figured the regulator died, so I got another alternator.
I replaced the alternator again. Ran the truck for about 5 min and started to smell electrical burning smell. So, I shut down and looked at wires and fuses. Nothing obvious. Any ideas? I'm posting this in the electric section too (I want to fix it tonite). Thanks.
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Laughing Gas
Joined: Oct 2003
Posts: 967
Likes: 0
From: DC
According to my manual, the volt regulator is attached to the back of the alternator. I just ran the truck for about 3 min, and the alternator got pretty hot. I don't think that's normal. It's kinda acting like a bad alternator, but I'm skeptical about that. The wires all seem to be cool.
Hotshot
Joined: Jul 2005
Posts: 11,932
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i think you have a bad ground or electric plug connection somewhere. the regulator is telling the alternator the battery is dead and go to full charge. thats why the voltmeter reads 18 volts. bad connection between the alternator and the plug or it sgound wire. look at all the ground wiere and plug connections to the alternator and junction box for the hot wires from battery.
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Laughing Gas
Joined: Oct 2003
Posts: 967
Likes: 0
From: DC
I'm not currently seeing 18v. I've got 13v with the engine off and 15v running (at the battery). I'll add a couple of things since, per my Haynes, the off and running voltages are about normal.
It looks like the voltage regulator is doing it's job, otherwise I'd see much more than 15v at the batt when running, right?
Alternator getting hot could be a few things. 1. Failing mecahnically inside. 2. Huge amperage draw like in a dead short. But, I haven't blown a fuse. Can't find any wires getting hot (especially big ones). Alternator casing sure is getting hot though.
The first alternator had similar symtoms. Ran it for 10 min or so with no problems, and then steady BATT light and pegged voltmeter (as if the volt regulator fried). Strange thing is after it sat overnight, I started it and had no light and the gauge was normal, almost as if something happens when the alternator overheats.
I really want to believe I got two bad alternators (three if you count the original) but, a little voice says I have a problem somewhere else.
It looks like the voltage regulator is doing it's job, otherwise I'd see much more than 15v at the batt when running, right?
Alternator getting hot could be a few things. 1. Failing mecahnically inside. 2. Huge amperage draw like in a dead short. But, I haven't blown a fuse. Can't find any wires getting hot (especially big ones). Alternator casing sure is getting hot though.
The first alternator had similar symtoms. Ran it for 10 min or so with no problems, and then steady BATT light and pegged voltmeter (as if the volt regulator fried). Strange thing is after it sat overnight, I started it and had no light and the gauge was normal, almost as if something happens when the alternator overheats.
I really want to believe I got two bad alternators (three if you count the original) but, a little voice says I have a problem somewhere else.
