Burning Main Fuses

[MrMarty51]

Pulled the under hood fuse/relay panel.
Does not look feasible to remove the underneath cover over the electrical contact for the ECM A and ECM B fuse connections.
The black plastic cover has no signs of excessive heat so back together the fuse panel goes.
Put this unit back together and runner till she blows.

 

[dbrannon79]

How does the contacts look where the fuse plugs into? strange there should also be a 25amp fuse in the dash panel that runs the blower. also powers the ac controls too. I bet that 50amp fuse also powers other things in the cab too. something you can do to check how good the contact is would be to take one of the old blown fuses and split it in half were you have that one spade to plug in. feeling for how much clamping force and resistance the spade had on the contact in the fuse box. then pull another and compare.

if it feels looser compared to other slots. sometimes but not always you can shimmy a L shaped pic in there behind the female pin slot and pry slightly to make it a tighter fit. if the female pin gets too hot the contact can deform and loose it's grip on the fuse thus creating a worse connection and more heat that eventually leads to melted plastic around that connection.

 

[MrMarty51]

With the IR thermometer, areas at both terminals reads the same temps.
Pull the fuses and both spades are heavily scratched in alignment with the female spade clamping lips.
I’ll see how it is getting to them terminals and see if I can get them snugged up some.
Fuses does pull hard from their receptacles.

 

[MrMarty51]

Running the fan and AC tiday and tge highest temp I could gain at the EMC2 fuse and holder was 160 degrees.
I think that new fan motor fixed the problem.

Above that group of red wires, a nut is protruding its head.

That nut is attached to the lug that secures the positive battery source to the fuse buss bar.
That lug was not tight and someone had installed a wire loop terminal under the head of the bolt then clipped off the wire and left the loop attached.

It is a bit croddy on the bus bar plate where the lug tightens it to the battery source.
Scrubbed and sanded it clean and a little corrosion preventive and now itiz clean and tight.
Also removed the nuts holding all the wires and cables from the battery and out to various feeds. Now all the lugs are ckean, protected and tight.

 

[MrMarty51]

It will now take some run time and miles to tell if the circuit is now dependable.

 

[Will L.]

Sounds like ya got it figured, but…

When following temperature on electrical- few things to remember:

The $50 & under temp guns aren’t super accurate on aim- it’s reading in a cone shape away from the lens. Closer is better but only to a certain distance- and the distance is different from one manufacturer to the next- so take time to read the specs and sharpie on the gun the optimal close distance.

Wherever the heat is highest- that is the point of most resistance (aka usually the problem).
Emissivity is a LIAR. This means shiny objects like copper, unpainted steel especially stainless or chrome and glass -gives completely wacked out readings.
Put a bit of black electrical tape on the surface to get accurate readings. The tape will take a minute to heat up but it will be closer than the reflective materials are. Flat black paint is excellent.

There are thermal imaging guns for $100-150 range that are nkt fit for professional use but are amazing for a mechanic or diy handyman stuff. FAR better than the little $50 laser point gun that only tells a number. With these you scan an area, wire harness, etc in 1/10 the time. And the more you play with it the better you get. - WARNING! NEVER in the sun. You can use it outside but point it at the sun for even a second and it is a worthless paperweight.

They come in very handy for things like finding studs in walls, finding where you are missing insulation, finding pipes behind walls, and even super early breast or similar cancer detection but isn’t used because it has a really high rate of false positives- but is the thing to tell you way earlier to pay attention over time.

If folks are interested, there are some instructional training books i can send pics of the more critical how to stuff privately - but I’M not allowed to share it publicly. But iirc there may be someone here who has a similar book they got at a yard sale or something and they could share it.

For my yob I have to be a level 1 Thermographer. Which basically means paying a grand or so for a week long class without falling asleep to learn how to use the wazoo level thermal cameras and stop things from going wrong before they would normally. At first I thought “could help in a few obscure situations.”
Several years into it I am thinking “I wish I had a $35,000 camera.” Haha.

In that video the hf96 comes out really well for $166. The downside it showed was the emissivity problem on the metal rim- but that is a normal problem for more accurate tools. Like I mentioned, sticking on a piece of black electrical tape (3m super 88 preferred) will eliminate that issue. Then remove it when done and go to the next task.

 

[MrMarty51]

Sounds like ya got it figured, but…

When following temperature on electrical- few things to remember:

The $50 & under temp guns aren’t super accurate on aim- it’s reading in a cone shape away from the lens. Closer is better but only to a certain distance- and the distance is different from one manufacturer to the next- so take time to read the specs and sharpie on the gun the optimal close distance.

Wherever the heat is highest- that is the point of most resistance (aka usually the problem).
Emissivity is a LIAR. This means shiny objects like copper, unpainted steel especially stainless or chrome and glass -gives completely wacked out readings.
Put a bit of black electrical tape on the surface to get accurate readings. The tape will take a minute to heat up but it will be closer than the reflective materials are. Flat black paint is excellent.

There are thermal imaging guns for $100-150 range that are nkt fit for professional use but are amazing for a mechanic or diy handyman stuff. FAR better than the little $50 laser point gun that only tells a number. With these you scan an area, wire harness, etc in 1/10 the time. And the more you play with it the better you get. - WARNING! NEVER in the sun. You can use it outside but point it at the sun for even a second and it is a worthless paperweight.

They come in very handy for things like finding studs in walls, finding where you are missing insulation, finding pipes behind walls, and even super early breast or similar cancer detection but isn’t used because it has a really high rate of false positives- but is the thing to tell you way earlier to pay attention over time.

If folks are interested, there are some instructional training books i can send pics of the more critical how to stuff privately - but I’M not allowed to share it publicly. But iirc there may be someone here who has a similar book they got at a yard sale or something and they could share it.

For my yob I have to be a level 1 Thermographer. Which basically means paying a grand or so for a week long class without falling asleep to learn how to use the wazoo level thermal cameras and stop things from going wrong before they would normally. At first I thought “could help in a few obscure situations.”
Several years into it I am thinking “I wish I had a $35,000 camera.” Haha.

In that video the hf96 comes out really well for $166. The downside it showed was the emissivity problem on the metal rim- but that is a normal problem for more accurate tools. Like I mentioned, sticking on a piece of black electrical tape (3m super 88 preferred) will eliminate that issue. Then remove it when done and go to the next task.

Looking into getting one of those.