Voltage drop at ballast resistor
^^I don't see this^^
I use a much simpler method. You are trying to find the SOURCE (which may be additive sourceS) of the drop
Hook one lead of your meter to battery POSITIVE. Extend the meter lead with a length of wire so you can "reach." This can be no 18, small wire. There is little current flow
Now access various points "as you physically can" in the PATH of the circuit
So if you work FROM the ballast TO the battery the drop readings should get less and less
Read at the resistor, key in "run." According to what the OP has posted this will be "a couple" of volts. It SHOULD be "a coupld" of TENTHS
Now read the blue terminal going through the bulkhead, both sides of the connector (ignition run) chase back to the ignition switch, ignition run, and power coming TO the key / connector. RIGHT THERE should show some change "I would think."
If not the next point is the "welded splice" which you cannot get to without pulling the cluster and untaping the harness so "skip it" for now
Next is the ammeter.
After that is the red terminals through the bulkhead
The readings should be less and less, nearly zero volts
WHERE THE DROP is happening is where the problem IS
Let's say "it is" the welded splice. Lets say you read the same (about) 2 volt drop at the ignition switch but the voltage drop "went away" at the black ammeter terminal
WHAT IS BETWEEN THE TWO?
A piece of black wire and the welded splice!!!!
==============================
Let's say the voltage drop still showed present at the black ammeter terminal (2v about), but the red terminal was OK (zero or much less, a tenth or two)
??? Now you have to be careful, because "bumping" or wiggling stuff could actually temporarily "fix" the problem. This is almost "worse" because it gets you onto a wrong track sometimes.
But what this just told you is that the problem is right there at the ammeter. It is either a bad wire terminal, loose terminal, or loose/ corrosion/ other inside the ammeter.
Quite frankly the TWO BIGGEST CAUSES in this particular case is the blue wire terminal going through the bulkhead, the ignition switch connector, and the switch itself
Also remember it is nearly NEVER a "wire." It is nearly ALWAYS a switch, or a connector terminal. RARE but has happened is a bad welded splice.
First one of those I found........was about 1972 in an apartment parking lot, in a friend's 68 RR. The ammeter had been jumping all around. I had the cluster and about half the dash harness torn down ........my first time doing so, and did not know where the splice was located WHICH I COULD SEE on the factory diagram. "He" (my friend) thought I was nuts. I was the hero after that day, LOL All it took was a great big Weller soldering gun
This is not the day we found this, but this is the car. This was at our RADAR shop on my day off. Don't remember who owned the shaker hood Cuda on left. Brown was a Poncho Ventura one of the guys I worked with. Next is my black 426 '64 Dodge. Next (facing) is Dave's 68 RR, this is the car that had the bad splice. At far right is my Limelight 70 440-6 RR
The 70RR itself had massive bulkhead connector problems "about then." I bored out the terminals for the ammeter and ran wiring directly through the connector. Both the original owner and I were radio amateurs, and we both had "gear" in the car
^^I don't see this^^
I use a much simpler method. You are trying to find the SOURCE (which may be additive sourceS) of the drop
Hook one lead of your meter to battery POSITIVE. Extend the meter lead with a length of wire so you can "reach." This can be no 18, small wire. There is little current flow
Now access various points "as you physically can" in the PATH of the circuit
So if you work FROM the ballast TO the battery the drop readings should get less and less
Read at the resistor, key in "run." According to what the OP has posted this will be "a couple" of volts. It SHOULD be "a coupld" of TENTHS
Now read the blue terminal going through the bulkhead, both sides of the connector (ignition run) chase back to the ignition switch, ignition run, and power coming TO the key / connector. RIGHT THERE should show some change "I would think."
If not the next point is the "welded splice" which you cannot get to without pulling the cluster and untaping the harness so "skip it" for now
Next is the ammeter.
After that is the red terminals through the bulkhead
The readings should be less and less, nearly zero volts
WHERE THE DROP is happening is where the problem IS
Let's say "it is" the welded splice. Lets say you read the same (about) 2 volt drop at the ignition switch but the voltage drop "went away" at the black ammeter terminal
WHAT IS BETWEEN THE TWO?
A piece of black wire and the welded splice!!!!
==============================
Let's say the voltage drop still showed present at the black ammeter terminal (2v about), but the red terminal was OK (zero or much less, a tenth or two)
??? Now you have to be careful, because "bumping" or wiggling stuff could actually temporarily "fix" the problem. This is almost "worse" because it gets you onto a wrong track sometimes.
But what this just told you is that the problem is right there at the ammeter. It is either a bad wire terminal, loose terminal, or loose/ corrosion/ other inside the ammeter.
Quite frankly the TWO BIGGEST CAUSES in this particular case is the blue wire terminal going through the bulkhead, the ignition switch connector, and the switch itself
Also remember it is nearly NEVER a "wire." It is nearly ALWAYS a switch, or a connector terminal. RARE but has happened is a bad welded splice.
First one of those I found........was about 1972 in an apartment parking lot, in a friend's 68 RR. The ammeter had been jumping all around. I had the cluster and about half the dash harness torn down ........my first time doing so, and did not know where the splice was located WHICH I COULD SEE on the factory diagram. "He" (my friend) thought I was nuts. I was the hero after that day, LOL All it took was a great big Weller soldering gun
This is not the day we found this, but this is the car. This was at our RADAR shop on my day off. Don't remember who owned the shaker hood Cuda on left. Brown was a Poncho Ventura one of the guys I worked with. Next is my black 426 '64 Dodge. Next (facing) is Dave's 68 RR, this is the car that had the bad splice. At far right is my Limelight 70 440-6 RR
The 70RR itself had massive bulkhead connector problems "about then." I bored out the terminals for the ammeter and ran wiring directly through the connector. Both the original owner and I were radio amateurs, and we both had "gear" in the car
