But... Looking at that picture... The slip ring looks in horrible shape. It may be a reflection, but it looks chewed up. The brush on the ground connection rubs against it and it should show a little wear, but that doesn't look right to me.
Please help - Keep blowing ALL bulbs, something is screwy with the charging system
- Thread starter barsteel
- Start date
barsteel
Member
Ok, I think I have it figured out, but need a little more advice.
I pulled the alternator to get it tested, just to rule it out. I took it to an old-time auto electric shop, where they owner mounted the alternator on his testing machine while I watched. "It's fine", he said.
I then told him what was going on...unregulated output at the batt terminal of the alternator, 11.9 volts at the battery, and a car full of blown bulbs.
He told me that I have a textbook example of a broken connection between the batt terminal of the alternator and the battery. "You alternator is working fine, but it has all this voltage with no place to go. It's passing through the bulkhead connector to the factory weld splice that feeds it to the lights, ignition, etc., but from there, it's not making it to the battery".
Smart guy.
He told me that I could simply run a feed from the batt terminal of the alternator to, you guessed it, the battery, with an appropriately rated fusible link. That would, of course, bypass the ammeter, but it would fix the problem.
I went back to my shop, reinstalled the alternator, disconnected the battery, and used my jump pack and a test light to check continuity of the wires leading up and away from the factory ammeter.
Alternator to engine side bulk head connector - check
Interior side bulk head connector - check
Power wire to the ammeter - check
Output terminal of the ammeter - NOTHING
Output terminal on the engine side of the bulkhead connector - check
Current through the fusible link to the starter relay - check.
SO...it appears as if I have a bad ammeter, ALTHOUGH I have seen the ammeter work SOMETIMES.
I know that the ammeter is a weak point in all early Chryslers, and there's typically problems with the shunt between the terminals.
I'd like to keep the factory ammeter if I can.
Am I better off just bypassing the ammeter and installing an aftermarket one?
Is there a way to fix the ammeter?
Any other advice before I tear the instrument cluster out?
Thank you.
Chris
I pulled the alternator to get it tested, just to rule it out. I took it to an old-time auto electric shop, where they owner mounted the alternator on his testing machine while I watched. "It's fine", he said.
I then told him what was going on...unregulated output at the batt terminal of the alternator, 11.9 volts at the battery, and a car full of blown bulbs.
He told me that I have a textbook example of a broken connection between the batt terminal of the alternator and the battery. "You alternator is working fine, but it has all this voltage with no place to go. It's passing through the bulkhead connector to the factory weld splice that feeds it to the lights, ignition, etc., but from there, it's not making it to the battery".
Smart guy.
He told me that I could simply run a feed from the batt terminal of the alternator to, you guessed it, the battery, with an appropriately rated fusible link. That would, of course, bypass the ammeter, but it would fix the problem.
I went back to my shop, reinstalled the alternator, disconnected the battery, and used my jump pack and a test light to check continuity of the wires leading up and away from the factory ammeter.
Alternator to engine side bulk head connector - check
Interior side bulk head connector - check
Power wire to the ammeter - check
Output terminal of the ammeter - NOTHING
Output terminal on the engine side of the bulkhead connector - check
Current through the fusible link to the starter relay - check.
SO...it appears as if I have a bad ammeter, ALTHOUGH I have seen the ammeter work SOMETIMES.
I know that the ammeter is a weak point in all early Chryslers, and there's typically problems with the shunt between the terminals.
I'd like to keep the factory ammeter if I can.
Am I better off just bypassing the ammeter and installing an aftermarket one?
Is there a way to fix the ammeter?
Any other advice before I tear the instrument cluster out?
Thank you.
Chris
Yatzee
Active Member
If you search the web, there are instrument service places that repair gauges of all types and also convert them. In your case perhaps redoing your amp meter to a volt meter might be the ticket. You can leave the face pretty much the same and have it marked for the proper volts reading. I would not use it as an amp meter again. Just search "guage restoration and modification" in Google and take it from there.
It shouldn't be that hard to find another used one.
BillGrissom
Active Member
barsteel,
The alternator guy's suggestion sounds spot on. The ammeter is the last thing in the path to BATT+. Ideally, it measures all current flow into & out of the battery. The exception is that it doesn't measure the transient under-hood loads (horn, starter relay, starter). I doubt the ammeter itself is bad since I think all it contains is a big "bus bar" and a magnetic needle that senses the large current flow. More commonly, the dash connectors are loose, corroded, or melted (common problem).
Yes, you can bypass the ammeter entirely in the engine bay, as he said. That will avoid the path thru the bulkhead connector. Search "MAD Bypass" on the A-body forum for a gazillion threads. You will be no worse off than a newish car that has neither dash ammeter or voltmeter. I guess they decided ca 1990's that drivers had become so girly that those gages were useless to them. Easiest is to get a cigarette lighter voltmeter, which I use on trips with my 1996 & 2002 so I'm not caught without charge (new cars go crazy at low voltage). I doubt you will find an aftermarket ammeter that fits you dash, but I think you could get a vintage one and recall it is easily removed from the rest of the dash.
The bulkhead connector is problematic in many cars as they age. If you have a 1965 (always tell us please), no problem since you have thick buss-bar feed-thrus for the thick ALT and BAT wires. They then decided that simple "56 terminal" spade lugs were sufficient, which was true for the 3 yr warranty but not decades later w/ corrosion = resistance = heating = melting. At least that is true for A-bodies. I know less of C-bodies. But, you could make your own thick feed-thrus, i.e. a big wire known as the "fleet bypass". BTW, that connector was probably more for factory assembly and not required. Later cars w/ many more wires for electronic controls dropped the connectors and use a solid wire bundle thru the bulkhead.
Finally, you have the "square-back" alternator. Don't change it, but do wire it correctly. It looks like your 2nd terminal is isolated by the plastic, but easy to check if it shorts to the case using an ohmmeter. If not, you need to connect a wire and run it to ground. BTW, the Vreg drawing you posted is of the 5 V Vreg "can" that plugs into the dashboard of ~1967 cars. The fuel and temp gage use that. In earlier cars (and those w/ tachometer dash to 1973), that Vreg is inside the fuel gage. The alternator's Vreg operates similarly, but has bigger parts like a thick coil. Both are primitive technology and better replaced w/ solid-state versions which cost $11 (under-hood) and $30 (dash).
The alternator guy's suggestion sounds spot on. The ammeter is the last thing in the path to BATT+. Ideally, it measures all current flow into & out of the battery. The exception is that it doesn't measure the transient under-hood loads (horn, starter relay, starter). I doubt the ammeter itself is bad since I think all it contains is a big "bus bar" and a magnetic needle that senses the large current flow. More commonly, the dash connectors are loose, corroded, or melted (common problem).
Yes, you can bypass the ammeter entirely in the engine bay, as he said. That will avoid the path thru the bulkhead connector. Search "MAD Bypass" on the A-body forum for a gazillion threads. You will be no worse off than a newish car that has neither dash ammeter or voltmeter. I guess they decided ca 1990's that drivers had become so girly that those gages were useless to them. Easiest is to get a cigarette lighter voltmeter, which I use on trips with my 1996 & 2002 so I'm not caught without charge (new cars go crazy at low voltage). I doubt you will find an aftermarket ammeter that fits you dash, but I think you could get a vintage one and recall it is easily removed from the rest of the dash.
The bulkhead connector is problematic in many cars as they age. If you have a 1965 (always tell us please), no problem since you have thick buss-bar feed-thrus for the thick ALT and BAT wires. They then decided that simple "56 terminal" spade lugs were sufficient, which was true for the 3 yr warranty but not decades later w/ corrosion = resistance = heating = melting. At least that is true for A-bodies. I know less of C-bodies. But, you could make your own thick feed-thrus, i.e. a big wire known as the "fleet bypass". BTW, that connector was probably more for factory assembly and not required. Later cars w/ many more wires for electronic controls dropped the connectors and use a solid wire bundle thru the bulkhead.
Finally, you have the "square-back" alternator. Don't change it, but do wire it correctly. It looks like your 2nd terminal is isolated by the plastic, but easy to check if it shorts to the case using an ohmmeter. If not, you need to connect a wire and run it to ground. BTW, the Vreg drawing you posted is of the 5 V Vreg "can" that plugs into the dashboard of ~1967 cars. The fuel and temp gage use that. In earlier cars (and those w/ tachometer dash to 1973), that Vreg is inside the fuel gage. The alternator's Vreg operates similarly, but has bigger parts like a thick coil. Both are primitive technology and better replaced w/ solid-state versions which cost $11 (under-hood) and $30 (dash).
mrfury68
Senior Member
I second checking all connections & grounds. Is your new VR the solid state type or the original breaker point style? The solid state type is much more accurate & trouble free. Just my 2 cents.
live4theking
Old Man with a Hat
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Did you ever get your electrical issues squared away????
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