Waterproofing the BCM

[bebe]

So I searched and found this thread:

H3 BCM Bypass/Delete

Here are some of the quotes from that thread that would apply to my inquiry:

Man the BCM is extremely integrated into your truck via hardwired copper and the CAN bus. It's either the gateway between other modules or listens and adds its 2 cents to almost every function. Losing it will likely mean losing ABS, traction control, stability control, as well as the little features like being able to close your sunroof after you key off but haven't opened the door. To take it out is to turn the truck into basically a mid 80's totally analog vehicle with a modern OBD2 powertrain which might not start due to the theft deterrent call and response interrupted by removing the BMS.

I have done a significant amount of work designing custom hybrid and EV powertrains in vehicles with modern electronics and I wouldn't even dream of trying to get by without the BMS even with all of my equipment and even if GM supplied with a .dbc file (so I don't have to reverse engineer the CAN bus).

Relocating it isn't so bad. The green/yelow CAN wires need to be a twisted pair to reject noise but that's literally no harder than twisting two wires. Usually you just put on end in a drill and twist away.

Frank

If there is no way to bypass it, my next step is to looking into extending cables, and moving the BCM up to the roof. It's not as simple as it seems. This needs to be done by some electrical pro because the BCM is very sensitive. Cables have to be compensated for extended length and shielded for any interference. Unfortunately I don't know anyone like that in my area.


"Ex Umbris Venimus"

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Hi Frank,

Thanks for the useful input. Looking at pics of the BCM, it seems like there are more than just the two CAN bus wires. Is that so in all the models, or only in the older. pre-CAN bus BCMs? I'm thinking that all the cables that come from all the sensors and lights, each has it's own pin. I have no experience with this, so please correct me. TIA

The BCM controls to much to consider removing it.

The thread seems to have morphed a little and I'm guessing the main reason is concern of the BCM getting wet. Waterproofing of electronics has made major advances in the past year. The industry is aimed mainly at mobile phones now, but there is no reason you couldn't have a BCM or PCM done. http://www.hzoinside.com/ There is another company with a very similar process that is aiming more for the post consumer market, but I cant remember their name.

Waterproofing these boxes makes a lot of sense. You can only move them so high and if it's not enough...

I've read some threads on PBB too and learned a little more: BCM's are heat sensitive, condensation sensitive, blah, blah blah. I saw some tupperware tricks, pelican case options, one of my friends used a tupperware container and put a vent tube on the top of it.

Still I think moving it is the best option. From the photo that Recon posted got me thinking (yeah i know....dangerous).

Would a company like Painless Wiring be able to make an adapter kit or a plug in extension to move the Harness up to the glove box or even up the A pillar to the headliner?

I have a spare BCM (well - it's actually a fried one) that I could fit a container around. Then venting it out the A pillar or even to the glove box for simplified access and protection. As long as it is vented it could help with cooling and prevent any condensation. Sealing the the plugs with Dialectic grease and siliconing the holes for the harnesses.

Might be just as tedious as relocating it, but having half doors and water crossings in my future is making me put a priority rush on this project.

Thanks!!

Bebe

 

[ReconH3]

I'm really contemplating moving mine up to where the sunroof motor and controls usually are. I have no sunroof. It's not that hard to do but you do need to consult with an electrical pro. Wires that long tend to have issues if not done right. It would be great if some company like Painless had an extension cable with male/female plugs built in. Unfortunately I won't be able to do anything till I get back to the US.


"Ex Umbris Venimus"

Sent from my iPhone

 

[Happy Hummer]

I've given this quite a bit of contemplation and was wondering if this new product available at the hardware stores would help slow some of the damage. It is a spray can product that is suppose to make the inside of fish tanks, boats, rafts and the like water sound again. I'm wondering if that could be sprayed onto the casing of the module and then apply dielectric grease to all connection points.

Chris

 

[bebe]

Flex seal???

 

[06 H3]

lol I see that damn commercial all the time! In my opinion I think putting it up high would be the best bet then if thats a problem go with waterproofing it in the stock location. One concern though for sunroof H3s is they leak sometimes and you would have to make sure they dont leak near the BCM.

 

[JoshuaL]

I think relocating it to under the center console would be the best bet for me. Like 06H3 said the sunroofs are known to leak and mine has in the past. If you do put it in the roof liner you may also think about how hot the roof gets with the sun beating down on it especially if it heat sensitive.

 

[06 H3]

Luckily or unluckily (depending on how u look at it) I have no sunroof but for the rest of u that may be an issue. I haven't even thought about heat issues either...

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[BW_Hummer H3]

I really wish mine didn't have sunroof, considering I never use it.

 

[MaxPF]

I can think of two solutions. First would be a coating that waterproofs the electronics. For that, Liquipel comes to mind. Second would be to machine a billet aluminum case, sealed with a gasket or RTV. It would basically be similar to the PCM, which is waterproof due to such construction.

 

[M22KLARS]

Second would be to machine a billet aluminum case, sealed with a gasket or RTV. It would basically be similar to the PCM, which is waterproof due to such construction.

You know... If it could be made cheaply enough I'm sure it would be a hot seller.

 

[bebe]

You know... If it could be made cheaply enough I'm sure it would be a hot seller.

Billet aluminum is not cheep - any kind of box could sweat and cause condensation, that would be my worry. it would have to be vented (I think) for cooling and evaporation.

Mine went when the carpet got wet one winter from a sunroof leak - it took over 6 months for it to finally doo the pooch, but the tech found condensation and corrosion around the BCM under the kick panel - but the carpet was dry.

 

[MaxPF]

Nothing billet is cheap. You would not want to vent it. Seal it airtight with a silica gel bag glued to the inside to absorb any humidity that gets sealed in the case. Or purge it with dry nitrogen.

Speaking of which, I have a cool idea to keep water out of my axles, trans, and t-case when doing water crossings. I'm talking about being able to have these parts submerged for prolonged periods without worrying about water weeping in past seals

 

[Happy Hummer]

Some real good thoughts and brain storming so far. I'd tend to agree that the box would be the best way to go. Unfortunately as has been discussed the billet aluminum would be quite expensive. I'm then wondering if potting it would be the ideal way to go. Completely submerge it in wax or urethane to coat the case?
I'm thinking the wax will melt but a urethane or shellac would be great. The spay I talked about seems to be a possible winner at a Walmart price!
Chris

 

[M22KLARS]

Believe me I know Billet isn't cheap. I guess when I was thinking about the project I wasn't thinking billet which is what was talked about as being used in the OG post.

 

[Steve #1]

I still think a process like Liquipel or HzO is the way to go. They are using these products in industrial A/C applications and with sensitive low voltage applications. There's no reason it wouldn't work for the BCM.
Relocating the BCM to above the glove box could probably be done by extending the wires. there is space there but you will need to remove the dash to be able to get to it and have any room to work. Moving to BCM to the roof has a couple flaws. I don't think the is enough space in the A pillar for all the wires so you would need to go up the B pillar. Second, if you get water up to the dash you will have lost so may electronics by that point, the BCM wont be getting input from anything so it won't matter if it still works or not.

 

[MaxPF]

I still think a process like Liquipel or HzO is the way to go.

Agreed. Lots of industrial electronics have similar conformal coatings on the PCBs, and for a good reason: they work.

 

[Peep]

If we coat the BCM with a water proof coating, will their be a heat issue?