Looking for the source of some starting/running issues related to wet weather so i took the cover off the ECU and found a gaping hole underneath the washer reservoir/ECU and a corroded ECU housing. When taking off the housing i found corrosion salt buildup inside so I did my best to cleanly and carefully get as much out as i could and am about to seal it up with some silicone.

There are two drain holes in the lower corner of the ECU. Should those get sealed up as well?

Here are pictures of what it looked like before I cleaned it up a bit.

 

If you seal the drain holes, you'll have problems with trapped moisture & condensation inside the case.

Don't. Just clean the case & paint it.

 

Heck of a place to put the ecu,right by a big reservoir of liquid!

 

Just got the new plugs and wires in (went to the bosch PT 4+ and magnacore 8mm) and the ECU cleaned, sealed, and reinstalled and the truck started up just fine and seams to have a little more umph too.. I still need to deal with the big hole in the wheel arch (which extends into the passenger side foot well too), but at least i'm not missing any more work this week.