Cab Module?
05-19-2023, (Subject: Cab Module? ) 
Post: #1
Cab Module?
I have a driver in our 2015 International Lonestar. He says he lost his overhead strobe light, bunk air condition, and power to his CB. I would guess there's more things that he's overlooking, but I'm trying to figure out what this could be? He says all of his instrument cluster is working. I would have thought if the Cab Module was bad that he would have lost his instrument cluster as well? Any help would be appreciated. I had him go through all the fuses on the passenger side dash. Are there any others we should look for?
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05-19-2023, (Subject: Cab Module? ) 
Post: #2
RE: Cab Module?
Might want to try disconnecting the batteries for a little bit. We've "fixed" a handful of bcms that way.
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 Thanks given by: RByrd
05-20-2023, (Subject: Cab Module? ) 
Post: #3
RE: Cab Module?
Prostar/Lonestar are notorious for gremlins when the smaller fuses in the fuse panel get tarnished. - I.E.> Even tho they are not bad yet. Instead of "checking" the fuses.. you need to replace all of the smaller fuses with brand new ones every so often, even if they are all showing good. Here are the fuses to replace on a similar post ...

ref: http://rawze.com/forums/showthread.php?t...1#pid12861


User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!.
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 Thanks given by: RByrd , Toolguy
05-22-2023, (Subject: Cab Module? ) 
Post: #4
RE: Cab Module?
(05-20-2023 )Rawze Wrote:  Prostar/Lonestar are notorious for gremlins when the smaller fuses in the fuse panel get tarnished. - I.E.> Even tho they are not bad yet. Instead of "checking" the fuses.. you need to replace all of the smaller fuses with brand new ones every so often, even if they are all showing good. Here are the fuses to replace on a similar post ...

ref: http://rawze.com/forums/showthread.php?t...1#pid12861

We replaced every small bus fuse on our fuse panel in the dash. None of the switches on our dash work (can't dump suspension, slide 5th wheel, etc) No power to CB, power mirrors don't work, windshield wipers DO work, but when you turn them off, the wipers stay in whatever position they are in when turned off. The speedo, rpm, and temp gauges all are working properly. Before I try to take it to a shop, I figured I'd check on here to see if anyone had any other recommendations?
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05-24-2023, (Subject: Cab Module? ) 
Post: #5
RE: Cab Module?
(05-22-2023 )RByrd Wrote:  
(05-20-2023 )Rawze Wrote:  Prostar/Lonestar are notorious for gremlins when the smaller fuses in the fuse panel get tarnished. - I.E.> Even tho they are not bad yet. Instead of "checking" the fuses.. you need to replace all of the smaller fuses with brand new ones every so often, even if they are all showing good. Here are the fuses to replace on a similar post ...

ref: http://rawze.com/forums/showthread.php?t...1#pid12861

We replaced every small bus fuse on our fuse panel in the dash. None of the switches on our dash work (can't dump suspension, slide 5th wheel, etc) No power to CB, power mirrors don't work, windshield wipers DO work, but when you turn them off, the wipers stay in whatever position they are in when turned off. The speedo, rpm, and temp gauges all are working properly. Before I try to take it to a shop, I figured I'd check on here to see if anyone had any other recommendations?
You need truck electrical diagram to look how power distributes. Very likely you have lost power bus connection +12 volt or ground.
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05-25-2023, (Subject: Cab Module? ) 
Post: #6
RE: Cab Module?
Two things. There are Mega fuses, usually on a panel off the engine side of the firewall on the drivers side. Those lose connection and/or corrode more often than they blow. In the battery box you may have "cube" fuses. If you have never seen them you probably wouldn't know they were there. They get covered with anticorrosion gunk when new and look like a black or red blob. https://www.google.com/search?q=cube+fus...e&ie=UTF-8

If it's not there you need a diagram. Pick something thats not on and work your way back to the batts. NAV does use the post on the starter solenoid as a junction point. Three or four feed wires are connected there. They are fusible links. The nut gets loose but that usually an intermittant problem. Fusible link is like a fuse but if it "blows" you can't see it, the wire insulation is special and is meant to contain the heat. It usually doesn't melt thru so you don't see the failure.

A link to NAV's public site for wiring info. https://www.internationaltrucks.com/body...-resources
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 Thanks given by: RByrd
05-31-2023, (Subject: Cab Module? ) 
Post: #7
RE: Cab Module?
Thank you for the info. I will look into both. We did take it to a shop, they replaced a few relays in the dash fuse panel and everything went back to working…. For 200 miles anyway, then everything went back off. I’m leaning towards a short somewhere that’s causing the relays to heat up but not sure. Will keep trying.
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05-31-2023, (Subject: Cab Module? ) 
Post: #8
RE: Cab Module?
(05-31-2023 )RByrd Wrote:  Thank you for the info. I will look into both. We did take it to a shop, they replaced a few relays in the dash fuse panel and everything went back to working…. For 200 miles anyway, then everything went back off. I’m leaning towards a short somewhere that’s causing the relays to heat up but not sure. Will keep trying.

you sure the guys CB is not causing it?... One of those illegal radios with more than just the legal 4 watts? ... . Seen people try to run powerful radios in these trucks and cause ghost problems like this too. Or Maybe some other device like, like a truck-stop brand of crappy power inverter that is nasty and noisy?.


User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!.
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06-01-2023, (Subject: Cab Module? ) 
Post: #9
RE: Cab Module?
I finally got the truck to our yard. It is the "accessory relay" in the passenger dash fuse panel. The relay heats up warmer than the others. Everything works fine for a while (sometimes an hour, sometimes 6 hours according to driver) I only got it to "trip" for me 1 time and as soon as the relay cooled off, everything came back on. I know this accessory relay provides power to the power mirrors, cb, 12v plugs, bunk a/c blower, 5th wheel slide control, and air suspension control. I replaced the relay with new and sent him 70 miles up the road to get some other parts and test drive and he said everything shut off twice in the 140 mile round trip. Is there a way to get the wiring diagram for this relay or does anyone know where it gets it's power from? All I know to do is start at the source and work from there? I'm assuming it's a bare wire somewhere?
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