Will not start because PCM, BCM, U/H relay fuse is constantly blowing when the ignition is turn on

Hi,

I don't feel the problem is the switch because the fuse is after the switch. So, that isn't the likely cause.

I did some digging and found the fuse you mentioned. It powers multiple components, any of which can be an issue. However, I noticed there is a 4way splice coming from it to the components that would be where I would recommend starting. Something at that point could be shorted.

If you look at the attached pics below, they are from the schematic I reviewed. I highlighted the wires I feel are the likely issue. All wires from the fuse are purple and the splice is under the dash on the right side (passenger's side).

Now, if you check the splice and there are no visible issues, trace the purple wires, one at a time to the components' they power inspecting for issues. If they all appear good, disconnect one of the components at a time to see if there is any damage at the connector pins. Also, see if the fuse blows with one component at a time disconnected.

That should help narrow things down. Here is a link that you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

Let me know what you find or if you have other questions. Also, when looking at the schematic, you will see the fuse is after power from the switch. Therefore, the switch isn't the likely cause.

Take care,

Joe

See pics below.