TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > Electrical - non engine
  New Posts New Posts RSS Feed - possible gauge issue?
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

possible gauge issue?

 Post Reply Post Reply
Author
Message
Have2SC's View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/30/2011
Location: Norwalk, OH
Status: Offline
Points: 1253
Post Options Post Options   Thanks (0) Thanks(0)   Quote Have2SC's Quote  Post ReplyReply Direct Link To This Post Topic: possible gauge issue?
    Posted: Sep/17/2021 at 3:20pm
    1970 Javelin with factory rally pack option and gauges.  Several weeks ago i started the car and noticed the car not running smoothly and the oil pressure needle on the gauge going bonkers then the car just quit like someone shut off the key. No lights, no nothing. Doin a little investigation we found a good battery.  We found power to the top small post on the rally pack junction block but none at the large post at the bottom of the block and no power at the alternator either. At the suggestion of a friend we attached a jumper wire from the small post to the large post on the junction block and we had power back. Figured at that point we had a issue with the junction block and got a replacement.  Replaced the junction block and it lasted about 30 seconds before doing the same thing!! On a side note after the second junction block we notice the oil pressure/amp gauge lens completely cracked from one end to another. Coincidence?  We feel we may have a issue with the oil pressure, amp gauge. Currently running car with amp gauge unhooked and having no issues of any kind. Is there a way to check this gauge? Anyone else have this problem.   Lee        
1971 SC360 Hornet 4 speed   1970 Javelin 390 4 speed "Base Model" 1967 Rambler 220 X code 343 4 speed
Back to Top
Trader View Drop Down
AMC Addicted
AMC Addicted


Joined: May/15/2018
Location: Ontario
Status: Offline
Points: 6751
Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Sep/18/2021 at 10:41pm
The problem with and Ammeter is that ALL the AMP"s  from the alternator run through it. If the old wiring is not up to the task, you can have major problems of overloaded wiring.
Suspect that the fusible link - wire used as a fuse has failed.
The gauge may be OK but definitely overheated. It can be checked with a known 12 VDC power source and load.
Use the TSM to find the fusible link location, close to the alternator.
Many times this will happen when alternator is upgraded for things like heavy AMP sound systems or headlights, but the wiring not upgraded as well.
The TSM is required to determine were the fault likely occurred and if wiring/alternator have been altered, this needs to be documented on a wiring diagram and loads traced, fused, connected orderly.
On my car, the halogen headlights are on relays and separate fuses - just an example. Not even going into the breaker in the headlight switch - you need the TSM, which by your vehicles posted, you already have.
Back to Top
Have2SC's View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/30/2011
Location: Norwalk, OH
Status: Offline
Points: 1253
Post Options Post Options   Thanks (0) Thanks(0)   Quote Have2SC's Quote  Post ReplyReply Direct Link To This Post Posted: Sep/19/2021 at 5:06pm
Originally posted by Trader Trader wrote:

The problem with and Ammeter is that ALL the AMP"s  from the alternator run through it. If the old wiring is not up to the task, you can have major problems of overloaded wiring.
Suspect that the fusible link - wire used as a fuse has failed.
The gauge may be OK but definitely overheated. It can be checked with a known 12 VDC power source and load.
Use the TSM to find the fusible link location, close to the alternator.
Many times this will happen when alternator is upgraded for things like heavy AMP sound systems or headlights, but the wiring not upgraded as well.
The TSM is required to determine were the fault likely occurred and if wiring/alternator have been altered, this needs to be documented on a wiring diagram and loads traced, fused, connected orderly.
On my car, the halogen headlights are on relays and separate fuses - just an example. Not even going into the breaker in the headlight switch - you need the TSM, which by your vehicles posted, you already have.
Trader, thanxs for the reply but the car is currently running without the amp gauge hooked up.  Main harness is a repop harness and what appears to be a repop rally pack harness.  Fusible link in main should not be the issue or the vehicle wouldnt run nor does it appear the fusible link in the rally pack harness is a issue so i am at a loss for the real culprit of the problem other than the possibility of the gauge itself.     
1971 SC360 Hornet 4 speed   1970 Javelin 390 4 speed "Base Model" 1967 Rambler 220 X code 343 4 speed
Back to Top
Trader View Drop Down
AMC Addicted
AMC Addicted


Joined: May/15/2018
Location: Ontario
Status: Offline
Points: 6751
Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Sep/19/2021 at 5:39pm
A loose terminal on the back of an Ammeter will create a lot of heat. If everything else is fine, it's likely the terminal connections on the back of the gauge.
Take the Ammeter out and test it. Look for any arcing on the terminals or heat damage on the connecting wires.
Back to Top
Have2SC's View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/30/2011
Location: Norwalk, OH
Status: Offline
Points: 1253
Post Options Post Options   Thanks (0) Thanks(0)   Quote Have2SC's Quote  Post ReplyReply Direct Link To This Post Posted: Sep/21/2021 at 11:17am
Originally posted by Trader Trader wrote:

A loose terminal on the back of an Ammeter will create a lot of heat. If everything else is fine, it's likely the terminal connections on the back of the gauge.
Take the Ammeter out and test it. Look for any arcing on the terminals or heat damage on the connecting wires.
Trader,  thanxs for the info, will see if that is the problem. 
1971 SC360 Hornet 4 speed   1970 Javelin 390 4 speed "Base Model" 1967 Rambler 220 X code 343 4 speed
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.688 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or