Driving & smelled wire electrical burning smell, pulled over, no smoke visible in cab or under hood. Smell went away. Drove to Oil change place for oil change, had them check battery & alternator. They said alternator only putting out 10.67 volts under load. Battery drained.Had vehicle towed home. Replaced alternator, charged battery for 10 hours. Now, pickup starts, everything appears to work but, battery light won't go out. Does this mean new alternator is bad? Is there a way I can test this?
The new alternator is probably ok.
I would say you burned a fuseable link in the wiring harness.
The alternator has a fuse wire between it and the battery to protect it from overload.
Have someone check the wires coming out of the back of the alternator. The big wire should have battery voltage, the small wires energize the alternator when you start the engine.
When I hook up a 12v test light to the negative battery post and touch the positive post I get a light. When I touch it to the negative post and touch it to the large post/wire coming off the back of the alternator I get nothing, with the engine running, of course.
When I touch the test light to one side of the MEGA FUSE 100A I get light on the red wire on one side but not to the red wide on the other side of the Mega Fuse.
So you are telling me the mega fuse is blown and there is no voltage at the battery cable on the back of the alternator. Have you replaced the fuse yet ?
I am automotively challanged, should there be power on both posts of that mega fuse with key off? How about key on/engine running? Both posts of the fuse have red wires. Is there a way for me to take that mega fuse out and test it?
Not to worry. Even the best mechanics miss stuff from time to time. Yes the mega fuse should have voltage on both sides with the key on or off. I would have to see the fuse to tell you how to take it out.
Took fuse out, tested it with a continuity tester and got nothing. Going to get a new 100A fuse. Will let you guys know. Thanks.
I would check the circuit for a short to ground before you put that new fuse in.
When an alternator goes out, I have been told that often it sends a "surge of power" that can blow fuses. Is that possibly what caused the Mega fuse to blow? They are only $6 bucks so, not a lot lost if it is not.
A surge is possible, but not common. You said you smelled wire burning, I'm going to bet the short that caused the smell and the blown fuse is still present.
Okay, I will check it out as best as I can. Any suggestions where to start? The wire between the alternator and the fuse block?
Probably. You may need a shop manual to get the wiring diagrams. I don't know if there is anything else on that wire besides the alternator. It may include circuits in the fuse box.
And the buring wire may have melted more than one circuit together somewhere in the harness.
Great, thanks. I will give it a try.
Sorry, I had to leave town early yesterday and never got the chance to pickup the part or complete the fix. I am going to do that this morning as soon as the roads thaw out. I will get back to you.
ALRIGHT! MEGA fuse installed, continuity tests good. Started vehicle, ran it for 5 minutes, then drove it around for 10 to 15 minutes more. No battery light, no wiring smell, everything appears fine.
Sounds good. Keep your fingers crossed on the burnt wire issue. Something had to cook that first fuse. Hopefully it was the original alternator.
When I was talking to the folks at the Napa auto parts & Speedee Oil they said that it is not uncommon for the alternator to give off a "Burning insulation" smell when it goes out. Also, I could still smell a little odor of it when I sniffed the old alternator. So, keeping my fingers crossed. They also said that id there indeed was a short, it should be evident within just a couple minutes.
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SOURCE: Bad Smell only when window is down...Smells like propane
no the ring and pinion seems ok from what you are saying...you wouldn't smell it up front while moving do to wind and what not,
oil can smell at low temps.
you may have an exhaust leak at an O2 sensor seal. or something relative to that.
SOURCE: coolant smell inside cab when you turn on car/heat
Likely you are in the beginning stage of a heater core leak. at this point, you may be able to temporarily solve the problem by using a good system sealer (I'm partial to the kind that comes as a silver powder) Since we don't actually know the condition of the core, temporary may mean a week or several years, but replacement is expensive and time consuming so I'd definitely give it a try.
SOURCE: Can an alternator drain the car battery in a few
Yes, the internal voltage regulator can stick and drain your battery in no time at all.
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SOURCE: Electrical Problem - dead battery
Sounds to me like you may need a new rectifier put in the alternator,a shorted diode in the alternator could be powering up things that should go dead with the key in the off position.To prove this,instead of pulling the fuse,take the plug out of the alternator and if all is well,you have your answer.
SOURCE: battery drain 2001 gmc 2500 hd pickup
On cold start up, starts fine.When i start driving all gauges needles start to sweep.. fuel empty to full spedo 0 to 100 amps and oil gauges sweep back and fourth. emerg brake gos on and off message center flashes battery in red and yellow.
seems like its possessed..
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