1997 Dodge Truck alternator intermittent charging

Tiny
RUT145
  • MEMBER
  • 1997 DODGE TRUCK
  • 6 CYL
  • 2WD
  • MANUAL
  • 326,000 MILES
My 5.9 diesel will quit charging when im driving if I open the hood and tap on the black box, that is the electrical connection to the back of my alternator, it starts charging again I thought this was the voltage regulator but u cant buy one. So I looked at your forum and it says the VR is in the puter so what is going on? My alt. Tests fine on the machine at the parts store. Thank you in advance rut
Friday, October 17th, 2008 AT 6:37 PM

3 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
It is true that the voltage regulation is done by a circuit in the PCM, but if you can tap on the back of the alternator and it starts charging, it must have a defictive brush or rectifier inside, or a loose connection, did you tap on it while bench testing it? I dont think the PCM would feel the tapping on the alt!
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Saturday, October 18th, 2008 AT 7:41 AM
Tiny
RUT145
  • MEMBER
  • 2 POSTS
I changed the alt and found a replacement contact block and now when I start the truck itwill charge for 10 secs then drop out then do this again 18 ttimes then it keeps charging. So far so good but I havent driven yet will find out tommorow is this cycling normal I dont remember it doing this before
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Tuesday, October 28th, 2008 AT 10:28 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Not really normal. Buit remember it is a rebuilt, try another one!
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Thursday, October 30th, 2008 AT 3:39 PM

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