Alternator case

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dart67

dart67

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I was testing some wires with a test light and noticed that the alternator case is (hot) lites up when the light was on it and the key is off, do I need to ground the alternator better? (74 duster with 360)
Thanks
 
Sounds like yes....but....

What 'light was on' when doing this testing? What was the - lead of the test light connected to?

Is the alternator and its brackets bolted well into the engine, with clean metal-to-metal contact? If so, then look at the ground leads from the battery to engine block and from the block to chassis.
 
Yes the test light lite was on, the lead was on the shock bolt , Ill check all the grounds
Thanks
 
LET'S START OVER!!!!!!!!!!!!!

1.......Are you sure your lamp is a 12V test lamp and NOT a continuity tester?

(That is, does this lamp have a battery inside?)

2.......The "shock bolt" is unlikely to be a good ground. It might not be grounded AT ALL. This is because shocks have those funny things, "whut" are they called? Oh yeah, RUBBER BUSHINGS

3.......WHAT KIND of alternator is this?

All the original type Mopar alternators from numbah 1 in the early 60's clear up into the 80's? are direct mounted to the block, and the BELT TENSIONER will ground it if nothing else

I'm speaking of the common, small frame type, either round or squareback:





What you are saying here, makes almost no sense at all without more SPECIFIC information

A photo of the test lamp and the alternator "might" be helpful
 
Your doing something wrong, if the case was "hot" ,12 volts, and grounded, something would burn! The shock bolt is not grounded. What problem are you having with the car or are you just playing with a test light?
 
KitCarlson said:
On the early style, the rectifier assembly near the output stud is not at ground!
Click to expand...

THAT is probably EXACTLY what the OP did!!!

The parts I colored in are not grounded
 

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I was removing my exhaust manifold and the wrench hit the alternator case and it sparked, I noticed that the power wire to the alternator has power to it even when the car is off, is that right?
Thanks
 
Yes, that output stud is hot all the time and is NOT fused, except for the "last ditch" fuse link up between the bulkhead connector and the battery

Originally, these had a plastic snap cover that "sort of" shielded them from such welding activities
 
That is correct. It is possible to damage diodes due to the inductive related spike from the short. It is always best to remove the ground cable at battery for any service work.
 
Thanks everyone for your help
 
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