lights flickering??
Thread Starter
Instructor
Joined: Jul 2012
Posts: 222
Likes: 0
From: Salisbury Maryland
lights flickering??
Has anyone had this problem?? when i turn my car on and its been running for about 5 minutes my lights start to flicker or dim. Once it starts every 5 seconds all my lights flicker for a split second. if i raise the rpm just a little and hold the rpm steady the lights dont do it and when i am driving it dont do it. only at idle i am having this problem. once i let it go back to idle it starts again. its like its on a timer, if you count to five seconds they flicker or dim for a split second then it doesnt do it for another five seconds. i replaced my headlights with the projectors and thought that might be the problem but i unhooked the power to the headlights and it still does it so it isnt the headlights. This affects every light thats on, interior and exterior. They all do it at the same excact time. also i hear a hum like my fuel pump running and when the lights flicker or dim the hum also stops at the same time the lights dim. If anyone has any suggestions i would greatly appreciate your input. thanks for anyones time!!
Last edited by glasguydj; Dec 10, 2012 at 06:11 PM.
Thread Starter
Instructor
Joined: Jul 2012
Posts: 222
Likes: 0
From: Salisbury Maryland
Thats whats crazy, if it was a bad ground wouldnt i have a problem as soon as i turn the car on . it dont start the problem until the car is warmed up and the choke drops of and rpms lower to regular idle. if i give it gas (just alittle) and rais the rpm by 100 the lights dont do it this is what has me puzzled.
Heel & Toe
Joined: Mar 2012
Posts: 22
Likes: 1
Has anyone had this problem?? when i turn my car on and its been running for about 5 minutes my lights start to flicker or dim. Once it starts every 5 seconds all my lights flicker for a split second. if i raise the rpm just a little and hold the rpm steady the lights dont do it and when i am driving it dont do it. only at idle i am having this problem. once i let it go back to idle it starts again. its like its on a timer, if you count to five seconds they flicker or dim for a split second then it doesnt do it for another five seconds. i replaced my headlights with the projectors and thought that might be the problem but i unhooked the power to the headlights and it still does it so it isnt the headlights. This affects every light thats on, interior and exterior. They all do it at the same excact time. also i hear a hum like my fuel pump running and when the lights flicker or dim the hum also stops at the same time the lights dim. If anyone has any suggestions i would greatly appreciate your input. thanks for anyones time!!
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Could very well be bad grounds. God knows Ive had my share of them:
BUT,,,,,,,,,,,,,,,, It could also be BAD POWER connections too.
Start at the battery.. Clean and properly tighten the battery cables. They MUST be tightened to 11 ft/lbs...
Examine the statrer solenoid. the power to and from the alternator goes thru the connections on the solenoid. Check the B+ connection on the back of the alternator for being properly tight and clean.
BUT,,,,,,,,,,,,,,,, It could also be BAD POWER connections too.
Start at the battery.. Clean and properly tighten the battery cables. They MUST be tightened to 11 ft/lbs...
Examine the statrer solenoid. the power to and from the alternator goes thru the connections on the solenoid. Check the B+ connection on the back of the alternator for being properly tight and clean.
1st Gear
Joined: Oct 2025
Posts: 1
Likes: 0
Lights flickering
Has anyone had this problem?? when i turn my car on and its been running for about 5 minutes my lights start to flicker or dim. Once it starts every 5 seconds all my lights flicker for a split second. if i raise the rpm just a little and hold the rpm steady the lights dont do it and when i am driving it dont do it. only at idle i am having this problem. once i let it go back to idle it starts again. its like its on a timer, if you count to five seconds they flicker or dim for a split second then it doesnt do it for another five seconds. i replaced my headlights with the projectors and thought that might be the problem but i unhooked the power to the headlights and it still does it so it isnt the headlights. This affects every light thats on, interior and exterior. They all do it at the same excact time. also i hear a hum like my fuel pump running and when the lights flicker or dim the hum also stops at the same time the lights dim. If anyone has any suggestions i would greatly appreciate your input. thanks for anyones time!!
Melting Slicks
Joined: Sep 2021
Posts: 2,555
Likes: 1,213
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
If it were me, I would, go to Autozone or Advance Auto and have them do a complete charging system test. If it only does it once in the morning when cold, that test may not help.
Have them test the alternator under load to make sure the alternator output is with in spec. Your lights are on a BATTER Y POWERED (Hot at All Times) buss so the ignition switch is not suspect in this circuit. There is a headlight HDLP Circuit Breaker that feeds the headlight battery power in the passenger's foot well fuse center. That could be suspect. Poor corroded/burnt/worn contacts can cause those symptoms. All the head light functions go through the column multifunction switch. It could also be subject. They fail frequently. (bad melted contacts) .
You could measure the voltage on the output of that breaker and see if it fluctuates with the lights.
Have them test the alternator under load to make sure the alternator output is with in spec. Your lights are on a BATTER Y POWERED (Hot at All Times) buss so the ignition switch is not suspect in this circuit. There is a headlight HDLP Circuit Breaker that feeds the headlight battery power in the passenger's foot well fuse center. That could be suspect. Poor corroded/burnt/worn contacts can cause those symptoms. All the head light functions go through the column multifunction switch. It could also be subject. They fail frequently. (bad melted contacts) .
You could measure the voltage on the output of that breaker and see if it fluctuates with the lights.
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