Puzzle for you electrical experts out there (1 Viewer)

Nov 17, 2007
Utah/summer Florida/winter
I'm struggling to get my 79 BJ43 from New Hampshire down to Florida. Last weekend I got as far as Baltimore before a loose alternator bracket caused a total electrical failure and some over heating issues to boot. Got that squared away but I wasn't completely convinced it would not happen again as the speeds I'm operating at and the road conditions on various parts of I-95 subject me to a lot of vibration.

This morning I started out from Chester, VA and after just under an hour I noticed the temp running high again. The same bolt bracket seemed to be the culprit. But this time after tightening everything down it seemed that the alternator was only producing electricity at idle and definitely not at highway speeds.

I'm guessing now Voltage Regulator or bad Alt diode or maybe a loose alternator connection ????? Doesn't really matter now as both batteries are dead and starting is out of the question till I can get the batts topped off again. Any ideas would be greatly appreciated.


Ron R

Drive a Landruiser, enjoy life
Dec 20, 2006
The Netherlands
There is no direct relation between your temp problem and the alternator not charging as long as the belt is sound and tight.
Because you say the alternator is charging at low RPMs I would suspect the brushes and/or slipring, but check the connections (alternator - batt ) and grounds as well.
Jul 4, 2006
Do you have a voltmeter? get one, check the voltage on the battery at idle and when you turn the throttle by hand, this will tell how the alternator behave. Between the engine and the frame there is a cable for the ground, maybe you have a loose bolt and you loose the ground when the motor is reving (higher vibration)
Nov 4, 2007
Is your belt slipping?

not generating electricity when spinning fast, and not cooling your engine down?

But I would think it would be really loud, and you would smell rubber...

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