Lights malfunctioning

Hi Faithforkell,

These two things don't really add up. If the alternator failed and the voltage was getting low, I would expect there to be a lot of low voltage DTCs. However, to answer your question, if the voltage drops below a threshold then the modules will start malfunctioning and it will do what is called load shedding. This means it starts cutting off operation of lesser systems so that it can keep voltage for more necessary items. This could explain what is happening.

I would suggest, replacing the alternator and battery if needed and then retesting.

If the ABS, traction control lights and others come on then there would be codes. I suspect the parts store's scan tool was not able to communicate with the ABS module. Some tools are not able to do this and if that is the case, then it would explain why they didn't get any tools. There is another possibility that the ABS module is offline and they just couldn't communicate with it. Again, a shop with an actual scan tool and not just a code reader will be able to tell if this is the issue.

Nevertheless, if the lights are on, we will need to find out what codes are in there otherwise we will be guessing at this.

Let me know what happens after you get a known good alternator on there are we can go from there. Thanks

Thank you. I replaced the alternator and the battery is new and nothing changed.

Okay. So if the charging and battery system are operating then can you tell me more about the incident that all these lights came on? When the lights came on what speed were you going? Did you hit a large bump? Were any of the tires spinning/loosing traction?

Also, are any of the lights still on or did they only come on momentarily and then go off?

I am just trying to understand what the possible causes are and hopefully getting a little more clarity on what happen will help with that. Thanks

I went ahead and paid for a diagnostics test and the mechanic said it was my power module not communicating and it would need to be replaced. He gave me a quote of $848.00 for the repair. I am not able to even find anywhere that sells a power module, so I am not sure what exactly needs to be replaced. I would prefer to just buy the part and install it myself if I can.

Okay. I assume they are talking about the Integrated Power Module. This is basically the main power distribution box. I included the procedure to remove this.

This makes sense as to what happened, but I would just make sure they found some evidence that this was the issue rather then them saying it is the likely cause. As you can see, it is a costly part that we want to make sure that this will fix it.

Let me know if you need anything else. Thanks

Update on the van: Replaced integrated power module and that didn't fix anything. Car shop said that they now think it's the body control module but that I would have to take it to a dealership. I found a used one and switched them out and nothing changed. Not sure where to go from here. I have an appointment with the dealership Tuesday but they charge $125.00/hour so I was hoping to figure it out on my own before then.

Unfortunately, it still could be the BCM. However, as I said before, unless they are giving you a reason it is the BCM like they have a code or did some diag it appears it is just a guess and that is why they said you should take it to a dealer.

Please see the attached document from the manual where is says not to swap BCMs with other vehicles.

At this point, I imagine you have spent more than $125.00 since the IPM was not cheap. Even if it takes them a couple hours to figure it out, it may be better than letting this other shop continue to guess at it, which is what it appears they are doing. If they just diagnose it, you may be able to do repair yourself but having someone with a scan tool able to evaluate this is what is needed.

The BCM controls the items listed in the second attachment. It appears to fit except for the ABS and brake light, or the AC system not working as you said do not fit but I would not get a new one until you have it checked out.