I have a 2004 Ion 3 that I've owned since new. The car has around 130,000 miles on it and has been a reliable and easy to maintain car since we bought it. Recently it has developed an odd issue however. The headlights will not stay in the same position with regards to high beams/low beams. There are times when the high beam indicator will come on during the middle of the day. This happens even when the headlight switch/stalk is in the low beam position. I imagine the high beams are in fact on when this is happening although I can't ell because it is daylight. If I flip the stalk back and forth between high beam and low beam, there is no effect. At night, the same thing happens but it is much more noticeable. I have no control over whether the car is in high beam or low beam. And most concerning, the headlights will randomly turn off and back on. They will turn off for as long as a minute or more, although sometimes its only for a few seconds. It just seems as if the car randomly flips between high and low beam, and off, with little regard for the position of the switch/stalk. Obviously this is very dangerous, and so we are not driving it at night right now. None of this seems to be related to going over bumps, etc, so I am not inclined to think its a loose connection somewhere. I have already replaced the switch/stalk with a brand new one with no noticeable difference. All of this is happening with the headlights in auto.

Any ideas?

Joe

Joe

 

According to the wiring diagram (attached), everything with the headlights is controlled by the BCM. The headlight switch and the multifunction switch (turn signal stalk) feed directly into the BCM, and the BCM sends the signal to the headlamps. The only other component, on vehicles with auto lamps only, is a headlamp relay located under the left side of the dash near the data link connector. You may want to check this relay.

 

OldMarine -

First, Semper Fi brother, I'm an OldMarine too.

Second, thank you very much for the info. Unfortunately, I just dug all around under the dash and even pulled most of the lower left portion of the dash out of the car. I can't find a relay down there at all. I know that a lot of what you are saying is coming directly off of that wiring diagram, but maybe it would be helpful to clarify terms.

One, I assume that the data link connector is the OBD2 connector. Is that your understanding?
Two, With auto headlights only. That could mean cars that only have auto headlights. It could mean only on cars that have auto headlights. Do you know which they mean?

My car has auto headlights in the sense that there is a sensor in the dash that turns the headlights on and off, but I believe there are manual modes as well. Based on that, and the terminology on the wiring diagram, do you think my car should have this relay?

Thanks again for the info!

Joe

 

I agree that your car should have the relay. Probably all level three Ions have the auto position on the switch. How do the lights behave when in the on position? 20 years old Body control modules are going to be the death of these cars.

 

Semper Fi to you, Chooko!

The data link connector is where you plug in a scanner/code reader, almost at the left kick panel in my car. My 2004 Ion 2 has only three positions on the headlight switch -- Off, park, headlights (symbols). And I'm pretty sure I don't have a sensor for ambient lighting. The wiring diagram stating that the headlight relay is for vehicles with auto lamps corresponds with the headlight switch shown on the diagram as a four-position switch. Presumably, with a three-position switch there are two fewer wires coming from the switch.

I suspect that the problem is with the BCM, and an outside chance that the headlight relay may be bad. I don't have a description of how all these components work with the headlights, so it's, at best, guessing on my part.