Here is a question I've been pondering. We know when the FICM draws more voltage it creates extra heat that the connections can't handle over time. So wouldnt it benefit it to have a large amount of heatsink fins in the top case part to release this heat? I have only seen one company that has an upgrqded FICM with a bit more heatsink on top. I'm just thinkin somethin more like you see on a processor in a computer. Any thoughts?

 

One of the main causes of failure is do to weak/faulty solder joints that can't take the current so the heat sinks would not do much in this case. If they really wanted to reduce heat they would get the FICM off of the motor and have it isolated from the high heat areas.

 

Bob, BPD played with that notion too, but overall decided it wasn't worth moving it, just fixing the board layout seems to fix the issues. I haven't had any repaired units come back either with some extra solder holding them down. However I've seen some really interesting things with a few of them. After a repair I typically just slap it back together quickly to verify the repair and don't stake the components down until after. I've pulled some off where the components actually "tombstoned" on the board. Meaning it was standing perfectly vertical. The only way for that happen is the board to get hot enough to reflow the solder! Motor heat isn't doing that...

BPD was just posting pictures on FB the other day of some temp testing they were doing...

No clue on the details of this though, as to whether or not the engine was even on or for how long etc, but they're at least testing it.

 

Those temps don't seem that extreme, if you have a laser temp gun, pull the lower panel off and get to the fuse box in the cab and hit the relays with the temp gun while the truck is running, have seen 140deg on the relays.

 

I was just thinking that residual heat build up would have to be playing some part in it. If it was strictly a current issue then its a poor connection that makes the amperage build heat that become detrimintal. Of course my only experience with heat in electrical connections comes from 480 ac power. Don't know how dc acts in that concept. Hope Yall can shed some light on it for me.

 

P=IxE it is all the same power/watts= heat it is more of a problem with the environmentally friendly solder not binding as goos as "real" solder. Have you ever wondered why harnesses are are just long enough on these trucks? because every inch they save saves them $$ when producing thousands and thousands of trucks. I don't think the heat is a major factor, yes loose joints will create heat too but the joint is loose before the higher heat is created. Just like finding hot spots in switch gear or at breaker lugs becaue something is loose causing the hot spot.

 

I got ya. Im starting to understand. And yeah I can understand the harness theory. I actually worked at a auto harness factory eons ago. Lol! So I see your point. Basically its Ford saving at our cost.

 

The FICM's are assembled in Mexico too, if that tells you anything. If you open one of these up and see how LITTLE solder paste is used, it's amazing they ever work at all. I've soldered quite a few of them and it's amazing how many will fly off the board when I hit the first side of it with the iron. That tells me the other side isn't attached AT ALL.