Quote:

"Sorry I know what you are thinking, but this test is not legit. When you disconnect the ECU, you will have no load on the ignition. You will in fact have an "open ended" harness. Even if the harness had considerable resistance, the meter draws almost no current, and you will show battery voltage OK on both sides.

ONLY WAY to check for voltage drop is WITH THE HARNESS UNDER LOAD, as in, "in operatation.""

Hey Yancy- You got nothing to be sorry about. I think you're jumping the gun... Circuit integrity comes way after we figure out if everything is wired correctly to begin with. If the ECU was tapped after the ballast, you're only getting 8VDC @ ECU no matter what. I guess you just want to take over? I feel sorry for this guy. This is what's bad about the internet.



WHAT IN THE 'ELL are you talking about???? If you unhook the ECU, there is no LOAD on the BOTTOM END, the LOAD END of the harness, and you will have NO VOLTAGE DROP across the resistor.

That IS what you said, right? Unhook the ECU and check the voltage?

I feel sorry for you. I've been around electronics since a very young age. I was first licensed as an amateur before I left high school. I spend 6 years in the U.S. Navy maintaining approach RADAR. I've troubleshot automotive electrics, maintained and installed HVAC/R, built some 250 HP dehumidifier dry kilns, and installed and maintained FM radio and telco gear for E911 systems for Motorola.

I have a good idea how the Mopar ECU system is wired and how it works, and I have an unarguable concept of voltage drop across a simple resistor

IT'S CALLED OHM'S LAW and there is a REASON why it is called a LAW.

I'm not trying to deflate your ego, I'm trying to point out that you are incorrect.

So let's go through this ONE MORE TIME

Refer to the diagram:

the below diagram is wiring for a "4 pin" ECU and "2 pin" resistor. The connector is shown "looking in" to the end of it rather than looking "down" on the back

IF YOU REMOVE the ECU connector, and measure the voltage at the Coil positive post AND at the dark blue "ignition run" feeding in, in OTHER WORDS you are measuring AT BOTH ENDS of the resistor, YOU WILL READ EXACTLY THE SAME VOLTAGE WITH THE CONNECTOR REMOVED FROM THE ECU.