PCM, BCM, U/H relay fuse keeps blowing

Interesting. So when them turned on that means we are probably bypassing something when they are off. Do you have daytime running lights or auto on headlights? Let me know how your vehicle is equipped and I will pull that info to see what could be causing the issue.

That is pointing me towards the BCM. At this point if it were me, I would get a BCM for it. Looks like you can get one for less then $100.00 if you can program it. If not, it will be about $100.00 after core return.

Clearly it is still a guess but looking at this wiring diagram the BCM is what will become a pass through when you turn the headlights on. When the lights are off, the BCM is what is determining what comes on and not. If the control side of the BCM is is shorted then it will overload that fuse. You turn the lights on and it is a straight pass through and the fuse doesn't blow.

As I said, this has not been proven but I look at the time it will take to prove out a short on a circuit board vs the cost of a known good one. With what you have found and this info, it is a pretty good bet that the BCM is the issue.

Okay. That adds to my assumption that the BCM is the issue. It controls the turn signals as well. Clearly this could be wrong but from my experience you have a lot of things pointing the BCM and you seem to have proven out most other items.

Clearly it is your choice but I would pull the trigger on the BCM and see what happens.

Yes. That is how I understand it but I have not purchased one of these from an actual parts stores. I always get them off online stores as they normally have better prices. I attached the options from the most common online site and they show both their options are already programmed.

Wow. Great info. Thanks for the addition to this post as I am sure that info will help others that have the same issue as well.

Please let us know if there are questions that we can help you with in the future. Thanks