Pennock's Fiero Forum
  Technical Discussion & Questions
  New, tested Alternator isn't charging - light is on, but no voltage at terminal B

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
New, tested Alternator isn't charging - light is on, but no voltage at terminal B by donridenour3134
Started on: 07-17-2014 05:21 PM
Replies: 3 (117 views)
Last post by: Bloozberry on 08-16-2014 05:30 PM
donridenour3134
Member
Posts: 41
From: Kokomo, IN, USA
Registered: Jul 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post07-17-2014 05:21 PM Click Here to See the Profile for donridenour3134Click Here to Email donridenour3134Send a Private Message to donridenour3134Edit/Delete MessageReply w/QuoteDirect Link to This Post
85 GT 3.4pr conversion. Alternator stopped charging, so I had it tested and it failed. New alternator also didn't charge. It tested good. The indicator light is on with key on engine not running and with engine running. There is very low or no voltage at terminal B on the alternator. BAT and A show normal battery voltage. The manual says volts should be between 2 and 4 at B. I've traced circuit to C500 and no volts for that wire (B3) there either. The fuse is good, the bulb is good. I don't know what to check next. Any help would be appreciated.
Thanks!

------------------
Don Ridenour
85 GT 3.4

IP: Logged
PFF
System Bot
donridenour3134
Member
Posts: 41
From: Kokomo, IN, USA
Registered: Jul 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post08-16-2014 04:26 PM Click Here to See the Profile for donridenour3134Click Here to Email donridenour3134Send a Private Message to donridenour3134Edit/Delete MessageReply w/QuoteDirect Link to This Post
Bump! No responses...Anyone?
IP: Logged
Arns85GT
Member
Posts: 11147
From: London, Ontario, Canada
Registered: Jul 2003


Feedback score: (1)
Leave feedback





Total ratings: 200
Rate this member

Report this Post08-16-2014 05:13 PM Click Here to See the Profile for Arns85GTClick Here to Email Arns85GTSend a Private Message to Arns85GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
Your C500 can get corroded, or one of the inline fusible links can fail. Best to test the battery terminals with the engine running.

You should get about 14 v across the battery terminals if the alternator is charging.

Arn
IP: Logged
Bloozberry
Member
Posts: 7760
From:
Registered: Jan 2009


Feedback score: N/A
Leave feedback





Total ratings: 308
Rate this member

Report this Post08-16-2014 05:30 PM Click Here to See the Profile for BloozberrySend a Private Message to BloozberryEdit/Delete MessageReply w/QuoteDirect Link to This Post
In the GT's, there is an in-line diode on the brown wire between the charge indicator and C500 pin B3. The diode is hiding in the wire harness below the rear bulkhead grommet in the engine compartment so you'll need to peel back the plastic loom. It's possible that your diode is fried.
IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock