Voltage drop with air on
Thread Starter
TECH Enthusiast
iTrader: (2)
Joined: Jan 2007
Posts: 519
Likes: 7
From: Northern Virginia
Voltage drop with air on Hey folks,
I don't know that anyone would know and it's probably a long shot. But my 1999 WS6 has an electronic draw when I turn on the air, both AC and heat. The battery meter drops below mid of the gauge then and the lights dim slightly. I've replaced the alternator and the battery which made a marginal difference. It also had a Bosch alternator on it prior to this, which was also experiencing a drop. I don't see any fuses blown. Do you folks happen to know where I might be able to find a likely electrical gremlin causing a voltage drop? Maybe the fan motor?
Thanks!
I don't know that anyone would know and it's probably a long shot. But my 1999 WS6 has an electronic draw when I turn on the air, both AC and heat. The battery meter drops below mid of the gauge then and the lights dim slightly. I've replaced the alternator and the battery which made a marginal difference. It also had a Bosch alternator on it prior to this, which was also experiencing a drop. I don't see any fuses blown. Do you folks happen to know where I might be able to find a likely electrical gremlin causing a voltage drop? Maybe the fan motor?
Thanks!
How low is it dropping? 13 volts or slightly under at idle with the fan blowing and other accessories on is normal. The voltage should rise a bit once the RPM comes up off idle. Don't forget when you turn the A/C on, that also turns the radiator cooling fans on. Those alone will draw quite a bit of power.
TECH Fanatic
Joined: Dec 2017
Posts: 1,467
Likes: 265
From: Bossier City, Louisiana
Use a multimeter and check for DC volts at the battery terminals with the engine and all lights, A/C, fans and accessories turned on. I will bet you lunch that the multimeter will show that your electrical system is actually at least a half a volt DC better than your dash gauge indicates. In other words, you don't really have much of an electrical problem. It's running OK, most likely.
If you really want to get ambitious here, clean up all of your grounds around the vehicle and you might recover another .2 volts or so of performance. More, if they are highly resistive.
Rick
If you really want to get ambitious here, clean up all of your grounds around the vehicle and you might recover another .2 volts or so of performance. More, if they are highly resistive.
Rick
Thread Starter
TECH Enthusiast
iTrader: (2)
Joined: Jan 2007
Posts: 519
Likes: 7
From: Northern Virginia
How low is it dropping? 13 volts or slightly under at idle with the fan blowing and other accessories on is normal. The voltage should rise a bit once the RPM comes up off idle. Don't forget when you turn the A/C on, that also turns the radiator cooling fans on. Those alone will draw quite a bit of power.
Sounds normal. Engine idling and everything off, turn on AC and rpm drops because of increased load ( takes power to run AC compressor), voltage drops because AC clutch is using some and fans (both radiator and cabin) are using some.
This is a great point. Every car has a voltage drop when the AC comes on, but it should not drop to the warning levels. If the voltage is in the normal when driving, I'd definitely check the idle conditions.
Trending Topics
Thread Starter
TECH Enthusiast
iTrader: (2)
Joined: Jan 2007
Posts: 519
Likes: 7
From: Northern Virginia
Do any of you folks happen to know where the grounds for the AC system might be?
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
