So I'm a new member. Just bought my first 90 xj Laredo. I have a 4 post brake switch that has a faint whine that stops when I gently touch the brake pedal. Anybody know what is causing that? I have other pesky issues that I will post about another time. Appreciate any input from all y'all

 

Welcome!!

Is it the white switch?

If so, it has vacuum to it for the cruise control to shut off when the brake is applied.

 

So if is whining it has a bad source supply? or leaking inside?

 

Probably doing what it's supposed to do but whining for some reason through the dump port.

 

Thank you... I was very curious what might cause this condition.

 

Thanks for the replies fellers. It is the black switch with two two post connections. If I disconnect the left side connector the whine goes away. It sounds like a muffled alarm when I reconnect it. I'm guessing it is the cruise control that is acting up. I've yet to engage the CC so I don't know if it even works. I also have idle issues which is apparently a major issue with these XJ's.

Hey cruiser54 I live in Prescott and I may have met you before in the past. Small world eh?

 

I'm not for sure how these are wired but could it be a brake light issue? One out or shorted?

 

LOL.

Ever buy Jeep parts off craigslist in Prescott?

Try unplugging the square yellow box up under the dash on the left side and plug the switch back in. See what happens.

Have you ever visited my website? www.cruiser54.com.
Do Tips 1,3,4, and 5.

 

So the brakes needed done so I did them. New pads, rotors, drums, shoes, fresh fluid. Brakes are better, but still got a bit of a mooshy pedal. Can't lock them up on a panic stop. Maybe I need to do a new master cylinder or brake booster. Still have that darn faint whistle from under the dash and the idle sits at about 1000 revs. This vehicle was used as a town car by three generations of female persons and appears to be well maintained. I'll keep messin' with it. Keeps me off a barstool.

 

Do this:

http://brakeperformance.com/bedding-in-rotors.php