Everything electric in my Pacifica 2005 has worked fine for several years until a few weeks ago when the high beam headlights stop working, Tested bulbs and column switch and found them Ok, The white wire of the bulb connector has zero Volts when the switch is operated, both If I connect a wire with 12 Volts directly to that connector then the bulbs turn on fine.

I learned from the forum that there are no fuses or relays involved in the highlights circuit that can be causing the failure, but this could be caused by a malfunction in the TIPM, how can I diagnose it?

 

There was a NHTSA recall for 2005 Pacs that involved the headlights, my Pac's headlights died, I got the dealer to replace the headlight harness & that fixed my issue. (attach)

Other than that, your headlights connect straight to the Integrated Power Module (IPM). So if the headlight-IPM cable is OK, it must be a IPM issue or an issue with a input to the IPM.

Good luck!

 

Since so much in modern cars is controlled by the computer, try disconnecting the battery for a few minutes before tearing it apart to find the problem.
It could turn out to be a minor software glitch.