Stupid place to mount a control module

[brianl703]

Back in the late 80's and early 90's we used to splash around on the Mojave river near me. Every Nissan hard body pickup left on a hook as the computer was under the pass seat. One good hole and it was ruined!

I think they eventually moved the computer to the transmission hump behind the center stack. At least that's where I think it is on the 1998 Nissan Frontier.

 

[researcher]

Side note, arent ECMs now located in the engine bay unlike years past when they used to live in the dash?

Ya.. I've started to see them in the engine bay.. with a shield to "try" and shield it from the engine heat! Remember.. Computers DO NOT LIKE HEAT! But let's put it next to the hottest part of the car! Bean counters at work saving the cost of extra distance in wiring away from the engine! Sure someone can tell me that MIL-SPEC computers can put up with so much, but when's the last time ANY regular automaker went to that level of specifications?

But hey.. that's just me!

 

[Ursatdx]

Maybe the chem guy will be along to explain aluminum corrosion.

Galvanic corrosion.

Galvanic corrosion (also called ' dissimilar metal corrosion' or wrongly 'electrolysis') refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte. It occurs when two (or more) dissimilar metals are brought into electrical contact under water.

What causes corrosion in aluminum?


If aluminium is exposed to very strong acid or alkaline environments outside the pH range 4 to 9, violent corrosion will occur in the form of metal pitting.

2 dissimilar metals in a salt solution?
As an owner of several boats it's common and can be expensive.
Looks like that box was immersed is a salty solution.
Add an electrical current to that and you've got a recipe for metallurgic failure.

ps. I drove by a Holiday Inn Express last night.

 

[Rmay635703]

I think the problem here is the leaving the window open and not the placement of the module?

Dodge puts the ecm on the firewall right next to where the water goes off the hood/windshield, if any of the gaskets loosen the truck misses and won’t restart unless you use a hairdryer

They also put a critical sensor on the top of the block in a pocket again similar situation, floods and creates missing and starting issues

 

[GON]

As someone who rebuildlt flood vehicles for a few decades, what that box displays is not exposure to a one time salt water, but was most likely rain water present at the location of the box for a very long time. Likely the water slowly entered the area where the box was located, and the water was not visually noticable to the driver of the car because the water entered the car under the carpet, not through the carpet. Very common issue in certain gm fwd sedans build in the 1990s and 2000s.

 

[Fordiesel69]

My favorite is when GM placed one under the seat, but screwed down to the floor board, and sold it as a chassis van for carpet cleaning companies. GM would not allow the outfitters to remove them and relocate anywhere else so each time the carpet machine would splash water out it would corrode the module, it was not long and airbags would start blowing at red-lights, and some when you would step on the gas pedal.

My 04 new body thru 08 f-150s that I have owned (not sure of other model years) they mounted the fuel pump driver module on the frame cross member near the spare tire, the the aluminum backing would rot away. The new design used a rubber and plastic spacer which helped but still rotted out. I replaced mine, and installed a zip lock bag around and siliconed it shut.

 

[chemman]

Galvanic corrosion.

Galvanic corrosion (also called ' dissimilar metal corrosion' or wrongly 'electrolysis') refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte. It occurs when two (or more) dissimilar metals are brought into electrical contact under water.

What causes corrosion in aluminum?


If aluminium is exposed to very strong acid or alkaline environments outside the pH range 4 to 9, violent corrosion will occur in the form of metal pitting.

2 dissimilar metals in a salt solution?
As an owner of several boats it's common and can be expensive.
Looks like that box was immersed is a salty solution.
Add an electrical current to that and you've got a recipe for metallurgic failure.

ps. I drove by a Holiday Inn Express last night.

Thanks! I could not have explained it better.

 

[WylieCoyote]

I didn't give much thought to the ECM location on my Focus ST until I discovered it one day while taking the left front fender liner out. There it was, right behind the bumper cover, filthy from years of being splashed by road water, so therefore not at all protected by the fender liner and engine tray. Dumb.

 

[nthach]

Side note, arent ECMs now located in the engine bay unlike years past when they used to live in the dash?

Yep - but that also coincided with better sealing for electronics. The IPxx specs define dust intrusion and water proofing - and PTFE membranes like Gore-Tex can be used as vents for ECMs.

It used to be that all ECMs got a coat of varnish as conformal coating and that was it.

Toyota always mounted their airbag ECUs in the center console below the radio with a plastic sheet to guard against liquid intrusion. It worked to a point.