2000 WJ 4.0 I6 with 82000 miles.

Noticed recently that I can hear an almost continuous clicking & whirring sound from under the dash but only when the headlights are on.
Sounds like a relay performing a series of clicks & whirring sound in a repeating cycle.

Any ideas what it could be ?

 

check into your BCM... I just learned about it the other day. Its like a PCM but its for your interior electronics. I was told if I want my interior lights working again Ill have to get a new BCM and rip apart part of my dash. I got other things to be fixing right now so I havnt gave this issue much mind lately

 

Relays click like that when they aren't getting enough voltage to hold the relay coil on. Suspect a corroded connection in the headlight circuit

 

i thought the bcm was under the center councel?

 

Traced the noise - not coming from under the dash - seems to be from the area around the drivers side headlight ( RHD ).
What could that be ?

 

Not sure, but I'll be sure to check back in another 40 days for the exciting conclusion!

 

It's the canister purge solenoid and it's working fine. You must not have very much valve clatter yet or you wouldn't hear it. It's mounted just in front of the brake booster and canister and if you put your hand on it, you can feel it cycle. The thing is IDK why you only hear it with the headlights on. It could be it's only part of a timed cycle determined by the PCM to only function at night. Seems weird, but now that I think about it, I have only heard it at night.