Pictures of Inside a VZ BCM

[bigdaddycool]

Unforunately I'm not at my dad's car where I can pull the BCM out and check it out.

Does anyone have pictures of what it looks like inside? for any VZ BCM.

I just wish to view it to have a look at possible points of failure. I get the feeling his BCM is faulty or possibly a earth around the car.... trying to same time if I can get a picture to rule out failure by bad design.

[andyman]

[delcowizzid]

hey anyman you mind if i put a copy of that pic on our delco forum someone might find that handy

[andyman]

yeah go for it


this is a mid level, see chart for bcm designations

[delcowizzid]

cheers mate

[bigdaddycool]

Cheers Andy. I just wanted to see the design layout. I've been told the ECU is sealed? Is it or do you have any pictures of that inside too?

[andyman]

Cheers Andy. I just wanted to see the design layout. I've been told the ECU is sealed? Is it or do you have any pictures of that inside too?

ecm is a sealed sandwich unit, so there is 2 circuit boards side by side in there, i think its then filled with resin so it cant short out, i think thats how they work

[bigdaddycool]

just wondering if there's any capacitors in there......... being mounted on the engine n all ......... in terms of an accident a power spike could possibly cause them to blow. looking at options atm with reguards to a head on crash issue we have with another vz

[Doctor Bob]

Whats the issue with the car??

[markovr]

anyone know which relay in the picture in this thread of the bcm internals is the one that sticks and causes the indicators to stay on when you lock the car? and can you fix it by just cleaning the contact or does the whole relay need replacing?I think its the smaller relay that is the only one of its type in the picture.

[dolsen]

anyone know which relay in the picture in this thread of the bcm internals is the one that sticks and causes the indicators to stay on when you lock the car? and can you fix it by just cleaning the contact or does the whole relay need replacing?

My one has started to do this, so, I'll let you know once I crack it open and fix it (won't be too soon though, new baby almost here, no real time at the moment). From the research I've done, the relays appear to be sealed, therefore, it will be a desolder and replace job.
Someone else somewhere (can't remember the reference) said that it was not due to the relay. Not sure if they were trying to make the job seem harder, or, if it's due to the driver to the relay. I'll trace it all back and see what is going on, but, the behaviour certainly suggests a relay sticking. If it was a bad transistor driving the relay, I'd expect it to go on and then stay on - until power was removed.

[PaulSV6]

anyone know which relay in the picture in this thread of the bcm internals is the one that sticks and causes the indicators to stay on when you lock the car? and can you fix it by just cleaning the contact or does the whole relay need replacing?

Yeah ur not the only one with this issue. its one of the two relays on the right

[impulsesv6]

what about when you have your headlights on "auto" then you drive into an underground carpark, turnoff the car, lock it, walk away and the headlights stay on

[markovr]

i think its a welded contacts problem and i think the relays arent easy to find as they have to fit perfectly to the pc board and they arent a jcar/dick smith type of item theres a bloke in victoria who can supply them but its no 10 dollar part.
Heres the datasheet for it
Drama because the pin configuration has to be exact you cant buy one over the counter in aust.....in hindsight you could run wires away from pc board and put any garden variety jaycar 20a minature relay 125 ohm coil resistance with 2 x no contacts and save quite a bit of money. The contacts are pretty small and over the years they burn and finally weld/stick themselves together. Theres a contact for left indicator and one for right ....thats why when they fail only one side sticks.

[dolsen]

My one has started to do this, so, I'll let you know once I crack it open and fix it (won't be too soon though, new baby almost here, no real time at the moment). From the research I've done, the relays appear to be sealed, therefore, it will be a desolder and replace job.

Having my wife call me yesterday as the car was flat and she had our new baby in the car and a 2yo moved the priority of the job up a bit...

At the moment, I've only done half the job, as, I didn't have time to source a relay. I've attached a write up of what I've done so far, which is basically just preventing the indicators from flashing when the doors are locked and unlocked to prevent the battery being run down.

I'll probably end up sourcing a different relay which is more commonly available, so, I'll write up about putting it back in when I do that step.

Note - I've only done half the job, so, use at your own risk.

Note2 – below is just a thought I have, not proven.
Looking at the datasheet, it states

“AgSnO2 contact is suitable for the lamp load, inductive load and motor load, while AgNi contact is suitable for resistive load.”

The AgSnO2 contact is identified by the code T.

Based on this, I would have expected the code to be
HFKM 012 SHST, not HFKM 012 SHS
I haven't looked if there is anything special downstream from this relay that would allow the resistive version of the relay, but, it could explain why there are so many issues from this part.
It is possible that Holden have a custom run of these relays that have the lamp contacts, or, there is some other explanation, so, it's not necessary because they used the wrong part.

Anyway, attached (I hope) is part 1 of fixing the vz sticky indicator.

[markovr]

Dont think that relay is a spare part you can easily source from our local holden dealership..bcm is bought as a unit from them ...had to get mine from a bloke in melbourne whose gone thru this and bought a number of them from china etc ( you can only buy them in 100s) and is selling them to get his money back and then some.
Youre lucky it only stranded you once..mine cost me a new battery that I didnt need...my 12 year old son pointed the stuck indicator problem to me after the battery was replaced......smart arse kids

[eaton v8]

ecm is a sealed sandwich unit, so there is 2 circuit boards side by side in there, i think its then filled with resin so it cant short out, i think thats how they work

do you know what each circuit board controls ?

[Adlikada]

I am new to this forum, well any forum really.

I have also had the same problems with my indicators locking up when I lock the car. I have discovered it is a relay issue, if I remove the relay the indictaors don't work at all obviously, but at least they don't stay on. I haven't checked to see if it affects the hazards or not, but the indicators still work when you need them too during driving.

I have also attached two pics, one of the4 588 MID BCM, and another showing everyone which relay it is that needs replacing. Be mindful that the relay seems to be impossible to find, as I have so far been looking for a replacement for around 14 months, and have still not found a reasonably priced one. Thanks Markovr for the relay pin spec, this will help greatly with finding a replacement I may just have to solder in using some fly leads, not the chosen way, but at least it'll work until I can find the correct one.

If anyone has an actual schematic of the BCM it would be greatly appreciated. Or at worst, what all the relays are for, and also the pin specs of the BCM connectors.

[bcw61]

I have also had the same problems with my indicators locking up when I lock the car. I have discovered it is a relay issue.

Be mindful that the relay seems to be impossible to find, as I have so far been looking for a replacement for around 14 months, and have still not found a reasonably priced one.

I have relays available if you need them. I've sent you a PM.