Chattering Relays above kick panel

[V8KiwiMan]

Hi all, Am new to this forum so please forgive me if someone else has asked before.

I have a VX SS Sedan gen3 5.7L Auto. It's done a good mileage (270K) and runs really well, apart from a couple of things. Firstly, there is a relay chatter coming from the front right of the car (above the kick panel) and I don't know where to start looking or what to look at. Is this the BCM here? Second issue, which could well be related, is that a few times just recently, when I have had cruise control on and have braked, the engine has revs have jumped up, almost like the cruise control was trying to override me braking, which is kind of scary when you are going around a corner that requires you to slow down to make it around safely. I don't know if these issues are related but am hoping the are....
Any wiring schematics that might be relevant or other information in regards to these issues is greatly recieved. Thanks all :help:

 

[meady_183]

relay chatter is normal. my car does it, and so do many others. the bcm is inside the passenger side kick panel. umm and the cruise control over-riding, im not entirely sure. sounds like a textbook faulty cruise control stalk. replace the stalk and let me know how it goes. i would also check the cruise module, and maybe even be getting another from the wreckers, and once again, at the very least check the connections and looms going to the cruise module. if unsure about anything, just ask.

 

[V8KiwiMan]

Im unsure how normal this relay chatter is. Some days there is no chatter at all. Other days the chatter is that bad that even turning up the radio to drown out the chatter doesn't really work. Just constantly have a relay turning on/off about 5 times a sec, or at least it sounds that fast. Almost like a bad earth somewhere. I still would like to know what this relay box does that is above the kick panel on the drivers side, what relays are in there.

 

[meady_183]

yeah, that much chatter isn't normal. open the fuse box under the steering wheel. there is a couple of relays in there. definitely flasher relay and others that i can't remember.

 

[V8KiwiMan]

I'm pretty sure that the relay chatter is coming from the fuse box. There is another box with looms going to it and I have a feeling that the chattering relay is in this one. The one I'm talking about is above the fuse box and tucked behind the insturment cluster almost. It is in a really bad place to get to in terms of seeing any identification labels or anything. Can try to take a photo to give you a better idea if that will help??

 

[Nut Kracker]

There is another box with looms going to it and I have a feeling that the chattering relay is in this one. The one I'm talking about is above the fuse box and tucked behind the insturment cluster almost.

Sounds like you are talking about the body control module.
Try and get a photo.
If you can. Start your car and wait for the chattering to start. Let the car sit there (stationary). When it starts to chatter, have a feel around where you think it's coming from. You should feel a vibration from the relay.

 

[V8KiwiMan]

Haha. Amazing what you find when you actually start looking. Turns out it is the BCM i was looking at. Anyone else had problems with the bcm having a very chatty relay? Ive managed to get my hands onto a full service manual qith electrical schematics but it has very little info on the bcm. Does anyone have a schematic for the bcm? Will it be safe to pull out bcm and open up to check for dry contacts and general condition of unit?

 

[Nut Kracker]

Haha. Amazing what you find when you actually start looking. Turns out it is the BCM i was looking at. Anyone else had problems with the bcm having a very chatty relay? Ive managed to get my hands onto a full service manual qith electrical schematics but it has very little info on the bcm. Does anyone have a schematic for the bcm? Will it be safe to pull out bcm and open up to check for dry contacts and general condition of unit?

It does sound like a dry solder joint causing intermitent contact. Just seems strange that you are not experiencing any faults with the car when that chattering starts.
Unless you know what you are doing, I wouldn't go mucking around with them.
Those things are full of IC's and chips and would be very suceptable to static discharge. I'd take it to someone who knows about them.
That's my opinion.

 

[V8KiwiMan]

I'm a sparky by trade so playing with this sort of thing isnt a problem for me. I havent had any warning lights flicker on the cluster while the relay chatters and no one has flashed me so can only assume my lights indictors etc arent misbehaving. Honestly dont know what relay it is. All i know is that it shouldnt be doing this. Would be helpful to know what the relays in the bcm do. And a layout drawing of the relays so if i find a dry joint i can get an idea as to what the dry joint is on

 

[Nut Kracker]

I'm a sparky by trade so playing with this sort of thing isnt a problem for me. I havent had any warning lights flicker on the cluster while the relay chatters and no one has flashed me so can only assume my lights indictors etc arent misbehaving. Honestly dont know what relay it is. All i know is that it shouldnt be doing this. Would be helpful to know what the relays in the bcm do. And a layout drawing of the relays so if i find a dry joint i can get an idea as to what the dry joint is on

I'm not trying to patronise you as this may benifit other people.
If you can't find a diagram, Have a realy close look at the solder joints, under a magnifying glass if possible. A "dry" joint as you should know looks, dry. Buy that i mean it's not as shiny as a good join. A good join should be nice and shiny and a bad one will have no or little shine. Having said that, it can be a hard task looking for a dry joint by eye, as there "can" be very little difference between a good join and a bad one.
A dry solder joint if looked under a microcope will appear to have crystilised. Therefore the solder is not solid and will not allow good contact between the two joined components especially if there is vibration concerned.
This usually happens if the join is very old, the soldering iron was not hot enough to melt the solder properly, the component(s) was/were moved during the soldering process or the components were not heated properly before the solder was applied. If the join is not very old, usually a quick dab with the iron to re melt it will fix it. If it's an old join, it's recommended that solder wick be used to remove the old solder and new solder applied.
Only looking at the relays, narrows this down alot though.

Sorry, didn't mean to write a how too.