How To Repair HMMWV EESS S3

[jantkovi]

Thanks for the info ryanruck. I'll check out the DeoxIT and Konform you mentioned. The S3 should be easy enough to remove and open up. My EESS had condensation build up inside that lead to corrosion. I would hate to see anyone have problems with a pricey S3 box. I'm seriously thinking about drilling a few holes in the bottom of my cover, so moisture can escape. I'm going to also make sure my electronics are coated to avoid corrosion in the future. Even though I had the foam donut on the upper cannon plug, to prevent water from coming in, I'm going to run a silicon bead around it to make sure water can't get creep in.

 

[Jakob1944]

Be careful on coating.....the IC's might use ambient air to dissipate their heat build up......

 

[jantkovi]

Good thought. The main concern is to protect the connections. The backside of my Printed Circuit Board (PCB) was even corroded in some spots (I've got pics). I"m thinking a light coating, in general, is going to be much better than what there was.

 

[86humv]

Those boxes have a rubber gasket, and a foam donut at the top to keep out water.
The old school boxes had vent holes and had goop all over electronoics.....those boxes were not real good, and long gone.
If I opened one and gasket was bad...I'd run a bead of sealant around it and put back together.
Then with box mounted with good donut and connector thru hole...I'd seal around connector .
Then connect harness.
Connector S/B tight for a proper seal.
I've seen trucks that had harness connector encapsulated with RTV sealant after they tightened it.
Also seal the 4 bolts, or studs on Box coming up thru the footwell tub.

 

[ryanruck]

Not having opened one up before, is there enough room inside to toss in a desiccant pack before sealing it up for good?

 

[jantkovi]

Not a bad idea. From what I've seen, the HMMWV is very well waterproofed. With the right equipment (deep fording), I've seen pics of folks in deep water with these things. I hadn't thought of the desiccant.

 

[Jakob1944]

I might ventilate mine to let it breathe....I don't anticipate any water crossing, at least not that depth.....It's pretty hot and dry down here in Central Texas......after all your car and truck AM/FM radios aren't sealed.....I think the corrosion is from condensation from temperature changes and maybe water crossing or fording with the boxes sweating on the inside.....just my opinion.......

 

[jantkovi]

When I opened mine up and saw the condensation, it was right after some rain and colder temps. It's a sealed metal box. FYI-There is a patent document, pointed out by another guy on the site, that shows where holes could go--https://www.google.com/patents/US6148258. This patent document basically lays out how the EESS should work.

 

[Jakob1944]

Maybe that box is as in use "one size fits all".......In other words being sealed the Humvee can be used in most application for a lengthy duration of time but the electronics will fail at some point requiring replacement.....Well they were built in the 80's and 90's so I guess 20 years plus on an electronic component is reaching.......

 

[86humv]

Not having opened one up before, is there enough room inside to toss in a desiccant pack before sealing it up for good?

If it gets hot inside...a bag would not be good.

 

[ryanruck]

I might ventilate mine to let it breathe....I don't anticipate any water crossing, at least not that depth.....It's pretty hot and dry down here in Central Texas......after all your car and truck AM/FM radios aren't sealed.....I think the corrosion is from condensation from temperature changes and maybe water crossing or fording with the boxes sweating on the inside.....just my opinion.......

I'd be worried about dust intrusion in your case. That can bring it's own problems.

I am a fan of neither water nor dust on electronics.

If it gets hot inside...a bag would not be good.

Yeah, that's something I'm concerned about. Not enough room for the electronics to "breathe" or a plastic bag potentially melting if something in there actually gets that hot.

But, I've got access to different kinds of desiccant packs aside from the standard plastic bag filled with silica. I've got clay filled ones that are packaged in crepe Kraft paper and and others in Tyvek. We use both types for transport and storage of metal parts and electronics. Uline has several options.

 

[Jakob1944]

Buy a new one and hope for another 20 plus years

 

[ryanruck]

I think the S3 boxes are a lot newer than that.

I'm sure someone more knowledgeable than I knows when they first started showing up.

 

[Retiredwarhorses]

I just grabbed this from another site

http://www.hummerknowledgebase.com/electric/eess.html

they are talking about the obsolete green label EESS, I personally don't like that box. What I like about the S3 EESS is they did away with after glow, I hate the 2mins of On and off.

 

[Jakob1944]

they are talking about the obsolete green label EESS, I personally don't like that box. What I like about the S3 EESS is they did away with after glow, I hate the 2mins of On and off.

mine doesn't have the "after glow".......but I get a needle dip on the voltage gauge (assuming it is the glow plugs' coming back on and off because of the cold engine......it'll do about 30/60 sec. and then smooth out......
The engine will fire up on the first turn

EESS....Nartron....12469158-1.......yellow label....

 

[Retiredwarhorses]

mine doesn't have the "after glow".......but I get a needle dip on the voltage gauge (assuming it is the glow plugs' coming back on and off because of the cold engine......it'll do about 30/60 sec. and then smooth out......
The engine will fire up on the first turn

EESS....Nartron....12469158-1.......yellow label....

what you described is "after glow"...

 

[Jakob1944]

what you described is "after glow"...

OK...I understand now after researching......thanks

 

[sward1999]

papakb, you wanna see if my s3 is repairable? I live north of Sacramento. Got an email?

 

[TOBASH]

papakb, you wanna see if my s3 is repairable? I live north of Sacramento. Got an email?

I see this is your first post... Welcome.

You realize this thread is at best 6 months old?

Maybe you might PM him directly instead. He still seems to be an active member with last post May 25, 2017

T

 

[sward1999]

Yup! I personally don't know anyone who knows how to work on these boxes.

Thank you.