Ammeter wires oh so hot!

woodwiz

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It was a good day here in the desert…Still can’t stop thinking about the folks in Florida that are not having a good day. A car issue is pretty far down their list of priorities at the moment
Got the new under dash harness in with a friends help.
Temp gauge came to life and new ammeter gauge seems to not be bouncing from the + to -
side anymore.‘Twas a good day!

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Russ69Runner

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Hope this is the solution to the hot wire issue. Sounds like you're getting all the bugs worked out. Good connections will make a difference and new wire over the old, tired wire is a plus. Maybe you can drive the car and not have to worry any more. :thumbsup2:
 

woodwiz

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Yup! That’s the plan…It’s cool’s down here in the desert & car shows are up next. Ya’ll have a good day!!
 

woodwiz

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The new harness is in along with the new ammeter gauge.
All is hooked up right,but I notice when running the ammeter leans just to the negative side but does not bounce around like the old one. Presumably that was due to a bad gauge and it’s insulation on the cluster. I also ran a 10ga. wire from the alternator to the start relay with a fuse link inline. Will that have a positive effect on the new gauge or harness?
 
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I also ran a 10ga. wire from the alternator to the start relay with a fuse link inline. Will that have a positive effect on the new gauge or harness?
If you want the ammeter to function correctly it's a negative effect, running the alternator to starter relay by-passes the ammeter altogether, defeats it's purpose. It’s not moving around because the charging/discharging current has been re-routed. The factory “fleet by-pass” by-passes the charge circuit bulkhead connections, the real weak link in that design, leaves the ammeter fully functional.
 
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Carl Ray

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What 72 is saying is, to get your Ammeter to read properly instead of connecting the "extra" 10 gauge wire to the starter relay connect that wire to the same side of the Ammeter you connected the RED harness wire to. Also, when most people do the this bypass they use 8 gauge wire.
 

woodwiz

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So now that I have the new harness and ammeter,running that additional wire from the alternator to the start relay w/fuse link I don’t see any movement on the gauge. Should I disconnect that wire?
Doesn’t seem like it helps. It wasn’t there before.
 

Carl Ray

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It helps because it takes load off the connectors within the bulkhead, but your Ammeter is not going to ready accurately the way you have it wired
 

woodwiz

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I agree! Run the wire as stated. The electrical system on Chrysler vehicles does not get a lot of applause around here,but with the new harness and ammeter gauge in I feel better about driving her and not waiting to smell smoke. I will be putting in the digital dash in the near future.
 

woodwiz

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When I first got this car I would open the door and notice the old ammeter gauge would bounce from the dome light. Then the gauge just stopped working and I inspected the gauge connectors and they got pretty hot. So avoiding a fire and getting it all redone is a good thing. Now I just have to figure out why my newer temp gauge moves up to higher temps erratically. Someone said there are 2 different types of sending units for temperature,one is for cars with idiot lights and those like mine with a gauge….Is this a possibility?
Thanks for all the help!!!
 
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Yes, idiot lights used a switching sending unit and gauges used a variable resistance sending unit. But only true for oil pressure on Chrysler products from this time. No idiot lights used for temp monitoring. Check the sender resistance to ground, should be about 74 ohms cold, decreasing to about 10 ohms full scale hot. The sensor lead touching ground intermittently will cause intermittent full-scale readings.
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What 72 is saying is, to get your Ammeter to read properly instead of connecting the "extra" 10 gauge wire to the starter relay connect that wire to the same side of the Ammeter you connected the RED harness wire to. Also, when most people do the this bypass they use 8 gauge wire.
To be clear, the “fleet” or bulkhead by-pass would involve a direct wire run from the alternator to the alternator side of the ammeter (black ammeter original wire) and another run directly from the battery side of the ammeter (red wire) to the fusible link, by-passing the weak bulkhead connections only.
 
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Also put a voltage meter on the battery when idling and unless I don’t have the meter set right the needle pegs all the way past 15v…any clues,did I hook up wrong?
Curious, did the over-voltage charging condition mentioned in the first post get addressed? The wiring discussion here wouldn’t normally resolve an over-voltage condition as described.
 

woodwiz

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That issue was resolved with a new bulkhead/underdash harness. That 10ga.wire was removed from the alt-start relay. Issues with this electrical system were crappy connections on the bulkhead and old ammeter gauge.
 
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Issues with this electrical system were crappy connections on the bulkhead and old ammeter gauge.
Just a quick note on the stock original "old ammeter gauge", in good shape, with correctly tightened/maintained connections, undamaged insulators, they don’t just fail for no reason whatsoever over time. The factory original ammeters are a simple device, stoutly constructed, with good connections, can handle a great deal of current. Problems begin with poor servicing of the stud nuts, left loose or oven-tightened (crushing the fiber insulators, leading to loose nuts-high resistance). Loose connections will build resistance and the resulting heat build up will cause even more resistance and insulator damage. Allowing a stud to twist while removing a stud nut will damage the internal stud head to bus connection and will contribute to even more resistance/heat build-up at the ammeter connections.

Another common cause of ammeter and charging system connection issues, for these cars still running an ammeter, is adding aftermarket loads directly to the battery/starter relay (or anywhere on the battery side of the ammeter). This creates a false charge indication as the added current is pulled though the ammeter, and all other charge circuit connections, from the alternator while in operation. This can place the entire charge circuit well outside of the original design current limits. For an original stock charging system configuration, all vehicle loads need to be on the alternator side of the ammeter, as are all factory original loads, no exceptions.
 
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