Bcm repair

[js1973]

Has anyone got a clue as to what fails in the bcm's
i have had a few people lately describe problems with vt and later bcm's causing flat batteries.
Also a wk statesman that flashes all sorts of faults like tail light blown when it isn't engine check light on interior light not turning off etc.
Would this be the usual bad solder joints or are their component failures that would cause these issues.
And if i pull out the bcm and resolder it will it disrupt anything like airbag warning lights etc.

[The1]

ive heard of relays failing in them, havn't tried to open one up and repair though.

[VL400]

Yeah a stuck relay could easily cause a flat battery. The random issues could be a dry joint but just as easily be a faulty component too. There is not much to a BCM, its really just a whole heap of inputs and outputs, RF and key reader circuit with a central processor.

Disconnect the battery, wait a bit and then remove the BCM and shouldnt have a problem.

[vnsswithcam]

the1 is right relays just stop working or they get stuck on causing the blinkers to stay on when you lock your car via remote key .... vz commodores are bad for it .... ive pulled one apart at work once i recon it could be repaired but havent tried it.....as for the check tail light coming up the bcm measures current it learns the current needed for all the lights etc when a light blows it will put the light on then in some cases when you replace the light the current draw is less than what its learnt due to old globes higher current draw etc... so it still puts the light on thinking one is blown!!!
take out bcm fuse for 10 secs... refit fuse then turn on ignition then turn on all lights one at a time leaving 5 sec gap between them once all lights are on including brake lights do it in reverse until all lights are off then switch ignition off and your bcm has now learnt the current draw and that prob should be sorted

[vnsswithcam]

flat battery take out power seat fuse under dash 20amp big silver metal fuse left hand side common problem for the switch to get stuck causing constant current draw connect a amp meter to the battery check it remove fuse if current drops theres your problem if it doesnt drop keep removing fuses until it does then you know what circuit its on..

[Holden202T]

had a similar issue in the ecotec torana ... be interesting to see if its flat, car has been sitting for 2 weeks while i've been camping ....

no memcal in it but we'll see i guess

[js1973]

Thanks for the input just wasn't sure if removing the bcm would interfere with the security in any way being a gen 3 not quite sure how they worked.
i will give it a try.
I have repaired a few earlier bcms from vs vr before was always bad solder joints or corrosion damage and one had a burn't out track on the circuit board wich oddly enough once repaired worked fine.