Forum | Marketplace | Knowledge Base | | H1 site | H2 site | H3 site
Click Here To Visit H-Line Conversions
Click Here To Visit H-Line Conversions
Click Here To Visit Tustin GMC/Hummer
Click Here To Visit Tustin GMC/Hummer
Click here for a listing of all HUMMER Network sponsors

Hummer Knowledge Base

The Hummer Knowledge Base

Voltage Drops at Higher Speeds:

If I drive my truck under 35 MPH, it's in the 13.8/14V range. If I go over 40 MPH it's in the 11.8/12v mark and go down further.. to 10v.


Drive in first with the engine RPMs at the same level as at 40+ MPH. Drops? Yes, then it is engine speed related. (Almost has to be anyway, but...)

Possible problems (in my order of checking):

  1. Belt(s) loose and slipping.

  2. Pulley slipping

  3. Bad brushes.

  4. Bad regulator.

  5. Other internal faults in the alternator.

One might ask how could the regulator be bad if it charges OK at idle... It may fail when asked to control voltage when speed is increased--this is not common but can happen.

Peter


Back to main page

The Hummer Knowledge Base is a collection of informative posts from the Hummer Network forums and mailing lists, contributed material and links to outside web sites.
The Hummer Network is not responsible for the accuracy of the information contained herein or on outside web sites, nor for any situation arising from the use thereof.
2006-2011 by The Hummer Network. No material from the Hummer Knowledge Base may be reprinted or republished in any form without permission.