Help ignition..here we go again,,,
Without knowing "under what conditions" these measurements are made, or what you are looking for, at least some of it is meaningless
The brown wire WILL LIKELY have a low value (you posted 5.3) with key on/ engine off. This is because you are not reading the brown wire, really you are reading the coil+ terminal voltage.
This circuit path is..........
Battery........harness........ign switch.........bulkhead..........coil resistor..........coil + ................. through the coil, and the coil is grounded out by the ECU causing the coil to DRAW CURRENT
So what you are measuring in this manner is the coil "loading down" the resistor, perfectly
normal
It is simply that the brown is hooked to the coil + just as your probe is
One thing you want to check, is "what is" coil + voltage with the key in "start?" This should be close to battery voltage, and in no case below 10.5V
++++++++++++++++++++++++++++++++++++++++
11.8..... this sounds like ignition "run" voltage coming out of the bulkhead and feeding the coil resistor, the ECU, the alternator field, and the voltage regulator.
This is LOW. Either the battery is low, or you have some voltage drop in that circuit.
A better way of checking this is to post battery voltage so you know whether the battery is low or not.
Then measure voltage drop directly by sticking one probe on the switch side of the ballast and the other probe on the battery positive post. This will give you the voltage drop (loss) from the battery........through the harness and connectors ...........and to the ballast 'high side.'
++++++++++++++++++++++++++++++++++++
When you disconnect the blue field wire you are relieving the ignition run line of some current, because the alternator field and the regulator are drawing current with key in "run." The 12.3, by the way, indicates the battery is probably "up" and that you DO have a harness voltage drop problem
++++++++++++++++++++++++++++++++++++++
When hooking up the resistor, you need to examine the resistor for the "U" shaped cutout in the ceramic. This "indexes" the resistor so that you can tell which half is which. This is actually two resistors in one ceramic block, and they are different resistances.
See this diagram:
See the upside down "U" in the resistor block at the bottom? In this photo, the right side of the resistor supplies the coil, the left side supplies the 5th pin of the ECU. The right side of the resistor is the SAME as the 2 pin resistor
Now look at this diagram:
All they have done here, for a "4 pin" ECU is to eliminate the left side of the resistor that was in the drawing above
You cannot always tell a 4 pin ECU from a 5, as many replacement 4 pin boxes actually have 5 physical pins. It's just that it's not connected to anything.
A 5 pin ECU must use a 4 pin resistor
A 4 pin ECU CAN use EITHER a 2 or 4 pin resistor, it's simply that the second resistor does nothing and is connected to nothing with a 4 pin box.
Without knowing "under what conditions" these measurements are made, or what you are looking for, at least some of it is meaningless
The brown wire WILL LIKELY have a low value (you posted 5.3) with key on/ engine off. This is because you are not reading the brown wire, really you are reading the coil+ terminal voltage.
This circuit path is..........
Battery........harness........ign switch.........bulkhead..........coil resistor..........coil + ................. through the coil, and the coil is grounded out by the ECU causing the coil to DRAW CURRENT
So what you are measuring in this manner is the coil "loading down" the resistor, perfectly
normal
It is simply that the brown is hooked to the coil + just as your probe is
One thing you want to check, is "what is" coil + voltage with the key in "start?" This should be close to battery voltage, and in no case below 10.5V
++++++++++++++++++++++++++++++++++++++++
11.8..... this sounds like ignition "run" voltage coming out of the bulkhead and feeding the coil resistor, the ECU, the alternator field, and the voltage regulator.
This is LOW. Either the battery is low, or you have some voltage drop in that circuit.
A better way of checking this is to post battery voltage so you know whether the battery is low or not.
Then measure voltage drop directly by sticking one probe on the switch side of the ballast and the other probe on the battery positive post. This will give you the voltage drop (loss) from the battery........through the harness and connectors ...........and to the ballast 'high side.'
++++++++++++++++++++++++++++++++++++
When you disconnect the blue field wire you are relieving the ignition run line of some current, because the alternator field and the regulator are drawing current with key in "run." The 12.3, by the way, indicates the battery is probably "up" and that you DO have a harness voltage drop problem
++++++++++++++++++++++++++++++++++++++
When hooking up the resistor, you need to examine the resistor for the "U" shaped cutout in the ceramic. This "indexes" the resistor so that you can tell which half is which. This is actually two resistors in one ceramic block, and they are different resistances.
See this diagram:
See the upside down "U" in the resistor block at the bottom? In this photo, the right side of the resistor supplies the coil, the left side supplies the 5th pin of the ECU. The right side of the resistor is the SAME as the 2 pin resistor
Now look at this diagram:
All they have done here, for a "4 pin" ECU is to eliminate the left side of the resistor that was in the drawing above
You cannot always tell a 4 pin ECU from a 5, as many replacement 4 pin boxes actually have 5 physical pins. It's just that it's not connected to anything.
A 5 pin ECU must use a 4 pin resistor
A 4 pin ECU CAN use EITHER a 2 or 4 pin resistor, it's simply that the second resistor does nothing and is connected to nothing with a 4 pin box.
