Police Camaro voltage drop *PLEASE HELP*
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Teching In
Joined: Apr 2012
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Police Camaro voltage drop *PLEASE HELP* So it started awhile back, I purchased an retired 2002 police interceptor Camaro off a lot near my house. After about a year the transmission went out(as expected). Being at school and not having my lift I purchased a new transmission and had it put in by a local auto shop. About a few months later I noticed upon startup my voltage will begin to drop once the power windows were used and the ac stopped working, along with the oil pressure sensor not working properly. The voltage than would drop to 8 volts when the headlights were turned on. After long nights of diagnosis and replacing the battery and alternator the issue did not go away. After about a year the issue became worse where upon startup the voltage will begin at 8 and then drop to red when using the power windows or turning on the headlights. The car then began having Vats issues where the security lock will engage and I was unable to start the car I chalked it up to the bcm and pulled one off another car to get reprogrammed. But before I paid 200 for Gm to do so I decided that After much frustration I took it over to Gm and shelled out 120 for a diagnosis. They then came back and told me that the alternator will charge at idle and then cease to after driving the car I don't know why this issue would be happening or what could cause the voltage and security issues.? The police Camaro came with 140 amp alternators and I currently have a brand new 160 amp one installed.
On The Tree
Joined: Dec 2014
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From: Mesa, AZ
Sounds like loose ground or bad alternator most likely. Get a voltmeter and check with then engine on, should be 13.5-14.5 volts with ac and everything off. Shouldn't drop under 13v with ac on and stuff like radio on. When you shut the engine off a good battery with proper charging system should be 12.6-12.8 volts with when the car is off. Just have someone start the car and measure it using a volt meter across the battery posts to see whats wrong. There should be be large grounding straps near the battery that you can visually check to make sure it's not torn or corroded too. By seeing what happens to voltage under loads and what not you should be able to identify the source of the problem
Last edited by McGinnis; Oct 11, 2015 at 05:58 PM.
Thread Starter
Teching In
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So I ran through the tests and everything checked out. But, I did see that the voltage gauge on the cluster was not displaying the same voltage. With the car running and the alternator charging the battery the gauge would read 12 v but I would read 14.5 at the battery. With the symptoms I've been exhibiting I believe it maybe a faulty BCM. I pulled one off a wrecked Camaro for 10 bucks and I will be taking it to GM on Friday to have it reprogramedreprogrammed. I will post the resultscompleted. e completed
Replace the voltage regulator electrical connector. I've had many many many camaros and TA's through shop same problem as yours and this has been the culprit almost every time. The factory alternator is notoriously short on power at full load for these cars upgrade to a truck alternator in future when the one on the car fails.
And search on here and do the big 3 upgrade it's mandatory and you won't be disappointed with the results.
BCM does not control alternator don't waste your money. When it starts having problems the windows and radio will intermittently not function.
And search on here and do the big 3 upgrade it's mandatory and you won't be disappointed with the results.
BCM does not control alternator don't waste your money. When it starts having problems the windows and radio will intermittently not function.
