06 trailblazer. Lights dimming, engine Kept cutting off when I came to a stop or let the engine idle. Was basically having to operate the gas and brake with 2 feet. Cleaned the throttle body, lights quit dimming and no more low idle or engine stalls.The idle should ALWAYS be rock solid at 600-625 RPM. Any time it dips below that when a load gets added, whether it's from the alternator or the AC compressor, the throttle body should instantly compensate. If the RPM dips to 500 or 550, and this is a lot easier to see on a scangauge or scan tool than the tach, then the alternator isn't going to keep up and stay in voltage regulation around 14V. Then the voltage will dip to whatever the battery can put out, like 12.1 to 12.5.
But my money is on a dirty throttle body when the idle dips, unless you have a true misfire. But misfires are usually bad all the time and then you get a flashing SES light, or bad for a short enough time that you get a P030X code for an identified misfire.
If the whine is not mechanically induced, it might be the High Freq "excitement" of the alternator as it is fed 400Hz to artificially induce the alternator to produce higher voltage to compensate for a low --- or going low --- battery voltage.I am not trying to lead anyone to say it was the alternator... but I'm open to suggestions.
BTW My TB has the same whine as the rest. Mine sounds like it is on the right side... I'm again thinking alternator...Yes the whine is RPM controlled.
STAY AWAY FROM PEP BOYS, they will sell you anything but you went in for. especially Garner, NC. go to advance or auto zone. at least they are honest, but still want to sell ya something. better than pep buys!!!!I have a 2006 and my issues are similar to several others but still unique. My wife informs me that when she was sitting at a stop light she says the engine acts like its going to die and the lights dim. So I drive it a cpl days and nothing. I took it to Auto Zone to see if any Engine codes were stored and "no codes". Finally it happened for me. I was sitting still and the engine RPM's dropped to 3-400. The lights dimmed. The Voltage gage showed 9.5 -10. The motor was NOT missing. It was running smooth. Weird.
I have a new battery installed. I put a voltage meter on the battery and was messing around turning things on and off... The normal reading with low "draw" was 13.9 - 14.1. I then turned EVERYTHING on I could and the idle dropped low again. The test reading was all over the place. Constantly moving from 13.75, 3, 10, 0.22, 5, etc. It bounced all over. So I thought alternator. So I went back to Auto Zone and had them run Diagnostic. The Alternator passed all tests. Weird
Now I am confused. I have no issues if I am just running "normally". Lights, radio, and heat on low ( 1 or 2) however if I turn on the heat or defrost to 4 or 5 when idle ling at light then it will drop down again and act like it wants to die.
I don't have the money to throw parts at it. I am not trying to lead anyone to say it was the alternator... but I'm open to suggestions.
BTW My TB has the same whine as the rest. Mine sounds like it is on the right side... I'm again thinking alternator...Yes the whine is RPM controlled.
Pep Boys says they will test the alternator for free if I take it off, but want $25 to test it on. It doesn't seem that easy to take off. I have basic to moderate skills.
Does this sound like anything to the Masters on here?
Mileage is at 110K if that matters. Battery is less than 2 wks old. Just replaced original battery due to cold temps.
sounds like the switch for ur heat/ac might be going bad/drawing too much power when switched to higher speeds…or the wiring to the resistor is heating up and drawing too much power….these things have everything regulated through the pcm and it has some sort of charge controlling crap in it so that it won’t turn in the alternator to charge all the time so it helps save horsepower somehow…I’m not sure how it works but it’s just another thorn in the side of the owner…when I first got my 05 trailblazer, it melted the harness to the resistor and fan in the passenger side behind the glove box…so I got another one…same thing happened…so I cut the ends of the melted harness off and put my own clips on and made it work….it worked for a few months then melts those off….what finally seemed to work was adding another foot of wire and putting a new harness end on it and then replacing the resistor…it seems the extra foot of wire prevents the harness end from heating up too badly and melting it…the resistor is a problem in these things…idk why they went all electronic with the heating cuz in the middle of nowhere and -28 degrees out and the heater decides to stop working almost made a bad situation much worse…the people who engineer these junk vehicles today are intentionally making them cheap and impossible to work on…there is no reliability with vehicles anymore and is why I won’t buy anything new …when I sell my trailblazer I’m getting a 98ish Dodge Ram with the 318 cuz they’re the last reliable model ever made…I have a 2006 and my issues are similar to several others but still unique. My wife informs me that when she was sitting at a stop light she says the engine acts like its going to die and the lights dim. So I drive it a cpl days and nothing. I took it to Auto Zone to see if any Engine codes were stored and "no codes". Finally it happened for me. I was sitting still and the engine RPM's dropped to 3-400. The lights dimmed. The Voltage gage showed 9.5 -10. The motor was NOT missing. It was running smooth. Weird.
I have a new battery installed. I put a voltage meter on the battery and was messing around turning things on and off... The normal reading with low "draw" was 13.9 - 14.1. I then turned EVERYTHING on I could and the idle dropped low again. The test reading was all over the place. Constantly moving from 13.75, 3, 10, 0.22, 5, etc. It bounced all over. So I thought alternator. So I went back to Auto Zone and had them run Diagnostic. The Alternator passed all tests. Weird
Now I am confused. I have no issues if I am just running "normally". Lights, radio, and heat on low ( 1 or 2) however if I turn on the heat or defrost to 4 or 5 when idle ling at light then it will drop down again and act like it wants to die.
I don't have the money to throw parts at it. I am not trying to lead anyone to say it was the alternator... but I'm open to suggestions.
BTW My TB has the same whine as the rest. Mine sounds like it is on the right side... I'm again thinking alternator...Yes the whine is RPM controlled.
Pep Boys says they will test the alternator for free if I take it off, but want $25 to test it on. It doesn't seem that easy to take off. I have basic to moderate skills.
Does this sound like anything to the Masters on here?
Mileage is at 110K if that matters. Battery is less than 2 wks old. Just replaced original battery due to cold temps.