I have an 06 Accord that has been electrically malfunctioning. When turning the key to the accessory position, power works. When turning the key to start the car, all power dies. Turning the key back to accessory does nothing and power remains off.

Leaving the key in the accessory position and doing something like opening and closing the door turns the power back on. Stomping on the floor board also occasionally turns the power back on. However, turning the key to start almost always shuts down all power again.

This happens about 1/5 times that I get in the car. The other times, it works just fine. It is hard to troubleshoot because it does not happen when I want it to.

I have examined all wiring under the hood, under the steering wheel, around inside fuse box, etc. Nothing looks exposed, loose, tampered with, etc.

Any ideas would be appreciated. Thanks!

 

Do you have a multimeter to test?

 

I do.

 

1. Disconnect the negative battery cable (you need the radio code and reset power windows afterward).
2. The driver’s door sill trim and kick panel can be removed to access the ignition switch harness connector at the under-dash fuse/relay box.
3. Unplug the ignition switch 6P harness connector. Test for continuity at the harness connector:

Switch position I (ACC): Continuity between Wht/Red wire (ACC) and Wht wire (Battery)

Switch position II (ON):
• Continuity between Wht/Red (ACC) and Wht (Battery)
• Continuity between Wht/Red (ACC) and Blk/Yel (IG1)
• Continuity between Wht/Red (ACC) and Blk/Red (IG2)

Switch position III (START):
• Continuity between Wht (Battery) and Blk/Yel (IG1)
• Continuity between Wht (Battery) and Blk/Wht (Starter)


Note: To test for continuity, set the multimeter to either the "ohms" or the setting it will beep when you hold the two leads together.
• If your meter beeps, it means you have continuity.
• If it is on ohms scale, you will have continuity when it reads close to 0 ohms.
• If it doesn't beep , shows OL (open line) or a 1 (infinity ohms); it means you don't have continuity.

Note: Blk/Yel is a wire with black insulation and a yellow stripe running through it. Other wire colors are referenced similarly.

 

Thanks for the reply!! Results:

Went out to the car and wanted to move it. Tried starting it, it started first try. This worried me that the tests might be false positives, tested anyway.

All tests were positive for continuity. Closed everything up, reconnected battery, went to start car... nothing. Since the problem was being replicated, I decided to take it apart and perform your tests again. All still had continuity. Closed it all up, car started.

EDIT - Actually, this test quickly failed once but passed the other ~10 times I tried. (Switch position III (START): Continuity between Wht (Battery) and Blk/Yel (IG1))

Definitely something sensitive somewhere that dies / comes to life with movement / tampering. I tried slapping everything around a little to see if I could find a sweet spot that was being affected by movement. No luck.

 

If there was no continuity between Wht (Battery) and Blk/Yel (IG1) in position III, even 1 times out of 10 when you tested, this would indicate any issue with the ignition switch or the wiring (less likely to be wiring in this case).

You can also test for voltage while they are still connected by backprobing that same connector harness. Backprobing is either using a backprobe set or using a thin needle or something and making contact with the metal terminal of the connector without piercing the wire in the back of the still connected connector. Care must be taken to ensure that the wiring does not get damaged. You can use something like a T pin, available at Walmart, etc., and backprobe. I've attached some pics. of the concept of backprobing.


When there is no power in position III .

1. Turn the ignition switch to START (III).
2. With a voltmeter, backprobe by touching the voltmeter's red lead to the Wht wire and the voltmeter's black lead to body ground (such as a bracket or bolt on car). Is there about 12 volts?

If there is ~ 12 volts on the Wht wire, then backprobe the Blk/Yel wire to see if there is ~12 volts on the Blk/Yel wire.

 

I can't get it to fail right now. I will try that next time it does. Thanks for your help so far.