Let's Talk 'Ballast Resistors'
The reason you would need a 4 prong resistor is IF you have an older "5 pin" ECU, and now you definately do not want to switch it around. If you look at this diagram, and a resistor, one end of the resistor has a U shaped cutout, which originall fit a "key" in the connector. That's how you ID the right end of the resistor
You cannot tell a 4 or 5 pin box by looking ALL of the time. Some 4 pin boxes have 4, some have 5 pins. So if you suspect a box with 5 physical pins is really a 4 pin box, you must use a meter on the 5th pin to discover if it's hooked to anything, or a dummy
Also, if you have the system correctly wired with a 4 pin resistor for a 5 pin ECU, you can use EITHER a 4 or 5 pin ECU
5 pin ECU, 4 pin resistor: "U" cutout on the bottom of the resistor
4 pin ECU, 2 pin resistor:
The reason you would need a 4 prong resistor is IF you have an older "5 pin" ECU, and now you definately do not want to switch it around. If you look at this diagram, and a resistor, one end of the resistor has a U shaped cutout, which originall fit a "key" in the connector. That's how you ID the right end of the resistor
You cannot tell a 4 or 5 pin box by looking ALL of the time. Some 4 pin boxes have 4, some have 5 pins. So if you suspect a box with 5 physical pins is really a 4 pin box, you must use a meter on the 5th pin to discover if it's hooked to anything, or a dummy
Also, if you have the system correctly wired with a 4 pin resistor for a 5 pin ECU, you can use EITHER a 4 or 5 pin ECU
5 pin ECU, 4 pin resistor: "U" cutout on the bottom of the resistor
4 pin ECU, 2 pin resistor:
