flickering alternator light
Thread Starter
|
Winching
Joined: May 2012
Posts: 676
Likes: 37
From: Wylie, TX
flickering alternator light
The battery light on the dash has random, intermittent flickering. Does not stay on. Battery is Interstate, less than 1 year old. I removed and cleaned battery connections. Starts strong. What can I test to find out what is causing flicker?
1- I plan to test the battery once my wife pulls the receipt to determine where we bought it.
2- The "small brown wire" that I was told could chafe, runs under the intake plenum. Don't want to pull that off to chase this wire.
3- Alternator is not loose, belt is new.
Ideas on how to go about this?
1- I plan to test the battery once my wife pulls the receipt to determine where we bought it.
2- The "small brown wire" that I was told could chafe, runs under the intake plenum. Don't want to pull that off to chase this wire.
3- Alternator is not loose, belt is new.
Ideas on how to go about this?
Pro Wrench
Joined: Nov 2015
Posts: 1,935
Likes: 189
From: Coastal Georgia
Have a meter? If so check batt voltage then start to check alt. voltage at same battery. No meter, purchase one, will need it in the future.
Or drive to one of big 3 parts stores and they will check it out for free.
If batt and alt checks good then look further.
......
Or drive to one of big 3 parts stores and they will check it out for free.
If batt and alt checks good then look further.
......
Last edited by number9; Jan 21, 2016 at 07:28 PM.
Thread Starter
|
Winching
Joined: May 2012
Posts: 676
Likes: 37
From: Wylie, TX
Tach not cutting out. Just a random flicker of the battery light from time to time.
I ordered a Multimeter online last night. I'm no multimeter expert but my basic understanding is check battery voltage first. If voltage within specs, start truck, check voltage while revving engine. If voltage ups to (I forget number) then drops, the alternator is charging. Last thing I heard was the positive terminal can be removed while running to see if the engine dies, in which case the truck is running off the battery. Don't think I'll do this, because the truck is showing no symptoms of weak starts or anything other than the light flickering.
I looked over all the wires again yesterday, the only wire I can't really trace well is the small brown wire that goes under the plenum.
I ordered a Multimeter online last night. I'm no multimeter expert but my basic understanding is check battery voltage first. If voltage within specs, start truck, check voltage while revving engine. If voltage ups to (I forget number) then drops, the alternator is charging. Last thing I heard was the positive terminal can be removed while running to see if the engine dies, in which case the truck is running off the battery. Don't think I'll do this, because the truck is showing no symptoms of weak starts or anything other than the light flickering.
I looked over all the wires again yesterday, the only wire I can't really trace well is the small brown wire that goes under the plenum.
I'm no multimeter expert but my basic understanding is check battery voltage first. If voltage within specs, start truck, check voltage while revving engine. If voltage ups to (I forget number) then drops, the alternator is charging. Last thing I heard was the positive terminal can be removed while running to see if the engine dies, in which case the truck is running off the battery. Don't think I'll do this, because the truck is showing no symptoms of weak starts or anything other than the light flickering.
A rudimentary alternator test without an amp clamp goes as following.
Connect positive to positive on battery and negative lead to chasis ground. .
Idle truck and look for constant voltage somwhere close to 14.V. Rev vehicle to 2000 rpm and turn on Lights( high beam), defroster, and heater on high, creating a load, the voltage should drop ( maybe a volt) and pick back up.
If this test is successful, drive until the engine is hot (15 minutes should do it). and retest. (Heat soak)
Your alternator may be shorting out when hot.
Results may vary.
Last edited by dgi 07; Jan 22, 2016 at 09:25 AM.
Thread Starter
|
Winching
Joined: May 2012
Posts: 676
Likes: 37
From: Wylie, TX
OK, will do, sounds like fun!
Have you made sure all your connections are tight?
A rudimentary alternator test without an amp clamp goes as following.
Connect positive to positive on battery and negative lead to chasis ground. .
Idle truck and look for constant voltage somwhere close to 14.V. Rev vehicle to 2000 rpm and turn on Lights( high beam), defroster, and heater on high, creating a load, the voltage should drop ( maybe a volt) and pick back up.
If this test is successful, drive until the engine is hot (15 minutes should do it). and retest. (Heat soak)
Your alternator may be shorting out when hot.
Results may vary.
A rudimentary alternator test without an amp clamp goes as following.
Connect positive to positive on battery and negative lead to chasis ground. .
Idle truck and look for constant voltage somwhere close to 14.V. Rev vehicle to 2000 rpm and turn on Lights( high beam), defroster, and heater on high, creating a load, the voltage should drop ( maybe a volt) and pick back up.
If this test is successful, drive until the engine is hot (15 minutes should do it). and retest. (Heat soak)
Your alternator may be shorting out when hot.
Results may vary.
Pro Wrench
Joined: Nov 2015
Posts: 1,935
Likes: 189
From: Coastal Georgia
......
Thread Starter
|
Winching
Joined: May 2012
Posts: 676
Likes: 37
From: Wylie, TX
Off, voltage 12.75
Engine idle warm 13.89 volts
Engine revved up to 2000 rpm, heater and lights 13.95 volts steady
Back to idle 13.89
Turn off heater and lights 14.08
Revved up no heater no lights 14.13
Hmmmmm. Not sure how well alternator is charging.
Engine idle warm 13.89 volts
Engine revved up to 2000 rpm, heater and lights 13.95 volts steady
Back to idle 13.89
Turn off heater and lights 14.08
Revved up no heater no lights 14.13
Hmmmmm. Not sure how well alternator is charging.
Last edited by jamieb; Jan 23, 2016 at 05:14 PM.