2001 Highlander Headlights Pulse?

[Scotty's Garage]

Any one out there have a pulsation of the Headlights on there 2001 Highlander. Does it at Idle or while driving around town/highway. Vehicle has 109K miles.
Thought it might be something with the PCM and need as reflash?
Liveable but it's anoying.

[jzack]

Sounds like perhaps an issue with the alternator (not supplying enough current under load?). Either go to Autozone for a free battery/system diagnostic or wire in a voltage meter to the cigarette lighter and monitor for voltage variations while driving around.

[Scotty's Garage]

Yeah that was done. Been there before. Usually the diodes go out when you jump someone. You will see a rise in the light intensity with a bad alt. as you bring the rev's up. That is not what I have. Lights are PULSING. Like a strobe light but very very quick. Lights are bright withy no dimming. Does it when it's cold or hot outside. Does it when the engine is cold or hot.
I've read where some Dodge's have had problems with Power Control Modules (PCM's). Didn't know if anyone has had that on there Toyota.

[jzack]

I've never seen this topic posted -- so doesn't seem to come up much ? My 2005 has never had this issue but that doesn't mean there isn't some strange liittle issue that shows up on a rare occasion?