Brakes pulsing with vehicle off?

[marin8703]

hey everyone,

Weirdest thing happened this mornig. As i went to the car and opened the hood to get ready to start changing my oil, i heard a quiet thumping sound. I narrowed in on the sound and it was right under the brake fluid reservoir, where the 4 little brake lines come out off.

The real crazy thing was that the truck was not started nor had it been for the past 8-10 hours. I hadnt even put the key in the ignition yet.

It thumps or pulses about once a second. I figure it was doing that all night, but how, without the ignition on or the key not even being put in; is ABS or TC active while vehicle is off and no key in???:confused:

Anyways once i put the key in and started it, then turned it off, it wasnt doing it anymore. I hope it doesnt do it again tomorow morning.

Have any of you people experienced this? Any idea why it may happen?

Thanks!

[Xof in H3]

Yeeaaahhh..... riiigght...

Have you thought about quiting drinking in the morning?

[marin8703]

Yeeaaahhh..... riiigght...

Have you thought about quiting drinking in the morning?

:) dude i am dead serious. i dont even drink:D . anyways my buddy was there too, we both heard it so i wasnt imagining things. It was weird as hell.:confused:

but it did happen and i have no idea how. anyone any plausible ideas?

thanks

[K9sH3]

Wait, there is a thread here somewhere where another 3 is always found dead in the driveway. And they have looked to see why it was always draining the battery, but have never found the reason. So, Maybe just maybe this could be legit and that persons problem also.

[marin8703]

yeah, i've seen that thread. could be same problem. Although i havent had any problems with the battery.

i know im not crazy cauze it happened again this morning and i got my neighboor to hear it too. Im expecting it to happen again tomorow morning so i got the camcorder sitting next to the H3 to record it and show you guys.

I wanna take it to the dealer, but i have a pertty good idea of what will happen. "we cannot duplicate the problem" bla, bla, bla.

ill get the video tomorow morning.

[K9sH3]

Great idea, but take your tape to the dealer. I have had all kinds of lil crap go wrong with mine. I like it, won't sell or trade it. But I do have my eyes on another Hummer. Good luck.

[marin8703]

heres a link to the video:

http://media.putfile.com/Brakes-pulsing-while-vehicle-off
PLEASE TURN UP YOUR SOUND, WAY UP, when trying to view the video. in the video ignore the clicking noise from the camera at the begining, towards the end i stop moving and making noise and you can hear it easier.

i will show it to dealer when i go.

here are some weird things i was able to figure out:
> It does not do this all night.
> in order for it to do it, the car has to have sat for at least 8 hours. then turn off the alarm. and open the door until you hear it start pulsing. if the door is held open for too long i can hear the (i dont know what its called, its the brake cilinder thingy i guess its what makes the pressure, sounds like a fan through a liquid) go on. after it stops making the "fan noise" there is no more clicking or anything until the ignition is turned on.

> this is all with no key in ignition (show it in the video)

any idea what could be cauzing this??? It sounds crazy!?

thanks

[K9sH3]

I am thinking you ned to get to the dealer, PLus I give you props for making the video. Let me know what happens at the dealer.

[marin8703]

well, in case anybody cares, when i took it to the dealer the service rep says its normal, but i called BS on that, and I was right. Now after 4-5 months finally figured out the problem.

My alarm/starter monitors the brakes by being hooked up to the brake switch on the pedal. When the truck is off, the alarm is working and there is solme leakby from the alrm over to the brake switch wire, which from there probably goes into the solenoid or computer or whatever, which makes the thing pulse.

The solution, for now i cut the brake monitoring wire, and this weekend will diode isolate it.

a happy ending, i hope no damage was done to anything thus far.:excited: