tramphardrocker

I posted earlier on about a muffled whine coming from somewhere behind instrument cluster (can't pinpoint it) on my 90 Cherokee Laredo. Maybe if I pull the dash I can find it. The whine stops when I barely depress the brake pedal. The white cc switch above the brake switch has a vacuum line to it so I assumed the switch/valve was faulty, leaking vacuum or misadjusted. Installed a new one and adjusted it per the jeep manual instructions (not fun)....but I still get that flippin' whine coming from behind the instrument cluster even after disconnecting all the cruise control components and plugging the vacuum lines. Is there an alarm associated with the cc system? Could it have anything to do with the brake switch since the cc valve has a wire connection to the brake switch? The cc switch on the steering column doesn't have any effect. I recently bought this xj (first one) so I don't have much experience or knowledge when it comes to troubleshooting this pesky bucket. I also don't know if this xj has a locking torque converter. This chump is stumped.

cruiser54

Kevin, there is no warning whistle or anything like that.

Yes, it has a locking converter that is unlocked when applying the brakes. That's why there are 2 plugs on the brake light switch.

I'm wondering if you have a brake booster issue causing the whistle.

That white valve/switch has 2 functions. Redundant. the electrical portion takes power from the cruise control system when the brakes are applied and the vacuum part makes damn sure it shuts off.