waterdog

As key rotates to ON position, I hear 2 sounds:
1. high pitched whistle
2. solenoid thump, half second later, as whistle continues for 1 second, then stops.
The red handbrake light is on, as is the yellow light on the fuel gage.
As rey rotates to RUN, whistle stops as engine cranks and starts, then whistle resumes for
another 1 second, then stops, as key springs back to ON, with engine running.
That's been 'normal' for the 11 years I've owned this 1994 Cherokee.
Problem is: the high pitched whistle sometimes continues after the normal 1 second.
Sometimes the whistle resumes, for no apparent reason...steadily... or intermittently, like morse code...while I'm in city traffic.
I loosened the 'speaker panel', see wires bundled with cable ties, and an attached
2"x2"x6" circuit board, with components, underneath a gray plastic open box above the board, with many colored wires entering the box from above.... but I can't easily see the whistling device, even when it's misbehaving.
Also, that fuel gauge is not operative, because the only fuel is LPG, which has it's own 6 color gauge, attached, and underneath, the 'speaker panel'. I removed the plum colored plastic 'chime' device(with 8 spade terminals).
Is the whistling device on that hand-sized circuit board?
Thanks for your advice.

BruceB

The sound description question...does the whistling sound you refer to sounds like a vacuum leak, a weatherstrip type of wind sound, or an electrical produced sound or some other source? And can you identify whether it comes from inside the cab, behind the dash or in the engine compartment...

waterdog

I googled "piezo sound" and found the following "piezo sound demonstration" video:
The 1st of the 3 sounds in the above video is what I hear.
The sound alerts the ignition switch ON position, and I always thought it was 'Jeep factory installed'.
But there's also a Dynatron alarm system, disarmed with a loud 'squawk' by remote button press, before I turn the key, or even insert the key, and that remote button also unlocks doors, as it disarms Dynatron.
This morning, minutes ago, whistle wouldn't stop, making it easier to hear, as I put my ear very close to another black box labeled "INT-WIPER".
And the whistle stopped when I squeezed and/or moved the wiper black box.
Before disconnecting the wiper box, I'll unclip the cable ties to loosen the bundled wires.
But the piezo 'sounds' as if it's within 3 inches of the wiper box.
Thanks again.

BruceB

There is a Hazard Flasher relay, the intermittent wiper control box and a combination buzzer that is on the inside fuse panel. I would start by disconnecting these one at a time and testing for the noise. The Hazard Flasher relay gets very hot to touch.....I would reconnect the "passed" components before disconnecting the next.

waterdog

The 'circuit board' I mentioned, is the interior fuse panel, not easily accessed, maybe because this Cherokee is "right hand" drive(originally in Japan in 1995, now in New Zealand, where we drive in the left road lane), and I saw a video of more easily accessed fuses on the passenger side of US Cherokees. I photographed board from below, which was easier than crawling below it. Also, the 'combination buzzer' buzzes(whistles) only for the one warning of 'key in run position'. The 'forgot key' and 'lights on' warning were chimes(bell tones) made by the plum colored device removed last week.
It misbehaved driving today. Back home, I only wiggled the gray device, spot number 1 on the board, and then the whistle became normal, for many attempts, (about 1 second of whistle, then silence).
Is that gray device in the upper left corner just a fuse, that can be pulled out?
Thanks again.





fusepanel, bolted underneath speaker panel

BruceB

both are 12 volt 30 amp fuses....if they are making whistling sounds, they may need to be replaced.