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Alternator light on but charging volts and amps good.

Sent to Car Experts September 16, 2004 5:52 p.m.

Alternator light on. 1984 Ranger 2.8L auto, ps. Charging system (voltage and amps) checks good. Iï¿½mwondering if there is a blown diode that used to block the current to the idiot light now letting current through? Or... the wires in this old truck are, ahem, aging. Maybe a short somewhere?
Thank you, Doug in western NC

Edited by Customer (name blocked for privacy) on September 17 2004 at 11:46pm

Customer (name blocked for privacy)

Status: Closed Value: $1

Answer
September 16, 2004 6:05 p.m. (12 minutes and 57 seconds later)

REPLIED

depends wher you checked the alternator..it may have a fuse link between the alternator and the battery..that will make the light stay on...dicconect the negative from the battery for 3 sec ( no more than that) and see if the car stops...if stops sice you say the alternator is good that is the fuse link or cable....i might be wrong but i say that it is unles a diode in the alternator is bad.

FeedMySheep -- Auto Mechanic/Technician -- 81% Positive Feedback on 87 Car Accepts
Operate Mercy Auto Clinic

Reply
Sent September 16, 2004 11:43 p.m. (5 hours and 38 minutes later)

Response to MercyAutoClinic's Post: I'm sitting inside as Ivan dumps its rain... not looking under the hood. But if I have the above response correctly, Mercy Auto Clinic is looking to check the connection between the positive terminals of the alternator and battery for an open circuit. To the best of my knowledge this path is intact. As evidence I submit that the battery is being charged to something around 14 volts, drives with the lights on at night, starts up everytime. I even left the lights on recently on a rainy day while I went into a store and it cranked just fine upon my return. If that fuse link was blown I will presume that the battery would go dead. Doug

Customer (name blocked for privacy)

Reply
Sent September 17, 2004 11:48 p.m. (1 day and 0 hours later)

Just refreshing the question to see if there is another response that makes sense for me.
Doug

Customer (name blocked for privacy)

Answer
September 18, 2004 8:37 a.m. (8 hours and 49 minutes later)

REPLIED

all wires at the battery are in the right place

as far as i know a light will stay on if:

the alternator belt is brocken

internal alternator problems

brocken or disconnected wires

defective voltage regulator

FeedMySheep -- Auto Mechanic/Technician -- 81% Positive Feedback on 87 Car Accepts
Operate Mercy Auto Clinic

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