Low Then regular voltage????


Old 02-27-15, 04:41 AM
Thread Starter
Join Date: Aug 2002
Location: Pennsylvania
Posts: 96
Low Then regular voltage????

Hi, I have a 2006 Chevy Uplander...runs good. Two nights in a row while I'm driving, the headlights will dim and at the same time the heater fan winds down a bit and the radio cuts out and then it goes back to normal....maybe a half hour later the same thing. Alternator? Any suggestions.
Sponsored Links
Old 02-27-15, 04:49 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 43,370
Many auto parts stores will test your alternator/charging system for free. I'd also check the connections on the battery and ground cable.
Old 02-27-15, 05:36 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,968
It's not a diesel, is it? In really cold weather, heater grids, if used, will kick in and put an enormous load on the system.
Old 02-27-15, 07:18 AM
Join Date: Jun 2002
Location: Northern Minnesota
Posts: 1,467
Not sure if this would apply to newer cars today but years ago I had a Cutlass that did the same thing--lights would dim then it would charge like crazy.

Turned out to be a part in the alternator, trio diode I think it was called. Easy fix if that is it.
Old 02-27-15, 08:21 AM
Rough Rooster's Avatar
Join Date: Feb 2014
Location: USA
Posts: 381
Check the chassis ground wire that comes off the negative battery post and goes to chassis. It is a smaller wire than the battery cable, but is interconnected with it at the battery connection and then goes to chassis ground. Corrosion and loose connections here can cause the symptoms you describe. I have cured these problems with new wires and adding an additional grounding wire from chassis ground to engine ground. Most notorious of these was the Jeep that lights and gauges flickered like a fluorescent bulb on its way out. Two new grounding wires cured it.
Hope your problem is as simple to fix. They can be difficult to diagnose, though.

Baldwin's suggestion is a good one also. It is called a diode trio and is inside alternator.

Happy hunting,

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes