1968 Charger Amp Meter/Electrical Issue

[kent_goins]

Went out to start my 68 Charger RT Yesterday and noticed a frightening problem for the first time. The Amp gauge drops to zero and all electrical power drops off momentarily for a split second. Then the amp gauge comes back on with a click and power is restored....Radio, lights and everything electrical shuts off for a split second. However, the engine seems to keep running fine. Probably because it happens so quickly. The distinct ping or click when the amp meter drops to zero sounds like a relay clicking under the dash. Anyway....anyone got any clues...LET ME KNOW!

KG

[73chalngr]

Sounds to me like ammeter is shorting out . I would disconnect the battery immediately because if it is a short you can fry other components  and inspect the ammeter if there posts are loose the ammeter needs rebuilt or replaced . I recently changed over to Rallye gauges in my challenger and that sounds similar to what the Rallye ammeter was doing  had it rebuilt ( took 4 months)  . I assume the electrical system is very similar also check the bulkhead connection under the hood for evidence of overheated wires. A lot of people bypass the ammeter and put in a volt meter because of this problem .

[Brads70]

   Disconnect the battery and get that gauge out for inspection/rebuild/replace! That was a warning shot. Not worth the risk of ignoring it. You could nut and bolt the ammeter wires together, tape real well  so the car is moveable and not disabled. 

[6bblgt]

  the 40+ year old ammeter is the source of many dash fires - heat & age takes its toll, repair/replace/rewire

[Mpdlawdog]

I had the same thing happen to my 68...I drove it one day and it started to smoke from under the dash..I shut it down and thank goodness it didnt catch fire....It melted the bulk head wiring all the way up to the gauge...I ran a new wire all the way up and did away with the bulkhead connection....connected the two wires behind the amp gauge and put in a volt gauge...easy fix

[303 Mopar]

    One of the first things I did on my '68 Charger was to disconnect the ammeter.  Simple way is to tie it together like @Brads70 said.

[kent_goins]

Thanks for the responses guys....i believe you are right. Is there a recommended manufacturer voltmeter to keep the correct look?
Thanks again for the responses and help! See attached for pic of my 68 beast...This is a picture at the Vanishing Point location where Kowalski comes across the tracks in Denver on his way to Argo's car delivery at the beginning of the movie. Argo's warehouse is to the left 1/2 a block. The whole area has been built up for yuppie living...but the streets are still there 

Regards,
Kent G.

[dodj]

Sounds like a short or open before the ammeter. (the ammeter, electrically, is already virtually a short, and they don't click).  That being said, I agree with everyone that says to replace it.
But I think you have another issue. Start by checking the bulkhead connector. Look for signs of heat, melting (signs of a short), or very poor/corroded connections (signs of an open).
When you say the ammeter drops to zero, the needle is right in the middle?

[kent_goins]

 No not in the middle. the ammeter swings all the way to the left on the gauge and all the lights flicker momentarily when it comes back to zero and then slightly positive at normal position

But A new problem has come up when I went to start the car tonight the wipers are not working 

[dodj]

Ahh. All the way to the left is max discharge,  not zero. You have a short after the ammeter. .....somewhere. not easy to find when it comes and goes. You can take the questionable ammeter out of your troubleshooting by simply removing the two wires from the ammeter and bolting them together.

[chargerdon]

I agree with DODJ...   your problem is a complete short...  and the probability of it being the ammeter is about 1%...   Terry in PGH (TLK) posted a thread that shows the insides of an ammeter...  there is nothing there except a direct bar of copper... 

Your real problem is probably the wiring that feeds the ammeter.  On my 66 it is only 12 gauge (not enough to carry the 45 amps of the alternator thru the plastic bulkhead connector then back thru the bulkhead connector to the starter relay.   I think the 68 is also 12 gauge...   It gets hot and can melt the bulkhead connector causing a short.    On my 66 Charger it actually caught on fire...right behind the bulkhead.   

I put in a completely new dash wiring harness and I did make the connections for the ammeter.   They are needed on a 66 to feed the 5 wire Butt connector that feeds the entire electrical system on one side, and to the Headlight circuit breaker on the other side, but, disconnected the wires going thru the bulkhead connector.   I then ran a new 10 gauge wire from the alternator, directly thru the firewall (with a grommet for insulation) NOT thru the bulkhead connector to the ammeter, then another new 10 gauge wire from other side of ammeter thru firewall to the starter relay...      The result is that i now have heavy enough wiring and the bulkhead connector is completely out of the picture, AND, I still have a functioning ammeter.   

Again, in my opinion the ammeter itself is very reliable, its the extremely poor factory wiring to feed the ammeter that is the real problem.   

Good luck !!   

[chargerdon]

Sorry, the post on the AMMETER gauge by TLK is on the 66-67charger.com web site.   Here is a link to that article:

http://www.66-67charger.com/forum/ubbthreads.php/topics/169603/The_ALT_gauge#Post169603

Hope it works

[kent_goins]

awesome...thanks guys!!!

KG

[dodj]

They are needed on a 66 to feed the 5 wire Butt connector that feeds the entire electrical system

That 5 wire splice exists on the e-bodies as well. 


As far as the ammeter being reliable, well, they are for certain length of time. But not a looong time and our e-bodies are old. And as you say the ammeter is just a copper bar - a calibrated one - but a copper bar none the less. The problem stems from the ammeter carrying the full load of the car. Full load current develops heat. That heat causes the copper to expand, just a bit. After you shut off the car, it shrinks back to original size. Now after several thousand cycles of expansion/contraction causes the ammeter connections (wires on the back) to be a little loose, a little more resistive than they were when new. So now you have .2 or .3 ohms where it used to be 0 ohms. Resistance causes more heat which causes more expansion...yada yada yada. A vicious circle that ends up in a meltdown.

Maintain your ammeter/connections and it will likely not give you any problem. But how many of us look forward to going under the dash every six months?
I used to hang half out the door, half under the dash trying to get my head in a position to see things......not so much anymore..lol Tooo hard on the back. 

[chargerdon]

DODJ...were pretty much in agreement.   One correction, the "bar" is actually brass according to TLK.   I believe it.   When i restored my 74 i had the dash cluster out, and there were NO indications of any problem with the ammeter...the connections were still tight and no signs of heat. 

I did have a problem however, with the connections at the bulkhead connectors...   Not anymore...on my 74 i ran bypass 10 gauge wire from the alternator straight to the starter relay.   This made my ammeter useless, so i replaced it with a voltmeter and the ground wire to the dash frame.   

On my 66 Charger is were i replaced both alt wire and return with 10 gauge wiring and NOT thru the bulkhead, instead thru existing holes in the firewall.  I left the ammeter in place, and all is working well.