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01-18-2022, 01:32 PM
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#1
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Mini-Skoolie
Join Date: Sep 2021
Posts: 16
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Brake lights out
My brake lights are not working when the brakes are engaged. They work during the lamp check, so I figure it’s not a bulb issue. I cannot located a fuse for them. All other lights working. Any ideas where the brake light fuse might be or what the issue is? It’s a 2007 international. Thanks!
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01-18-2022, 03:30 PM
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#2
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Bus Geek
Join Date: Sep 2017
Location: Swansboro,NC
Posts: 2,973
Year: 86
Coachwork: Thomas
Chassis: Ford B700
Engine: 8.2
Rated Cap: 60 bodies
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you should have a brake light switch.
usually mounted on the brake pedal.
unless your bus has something different.
but has to know when you press the brake pedal
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01-18-2022, 05:37 PM
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#3
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Bus Nut
Join Date: Dec 2020
Location: Las Vegas, NV
Posts: 261
Year: 1995
Coachwork: Bluebird
Chassis: International 3800
Engine: DT466 / MD3060
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Maybe dumb question but if you have air brakes, is there air in the system?
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01-18-2022, 09:31 PM
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#4
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Bus Nut
Join Date: Jul 2019
Location: Suburbs of Winterset, OH
Posts: 802
Year: 2005
Coachwork: Thomas
Chassis: FS65
Engine: Mercedes 6.4L
Rated Cap: just the 2 of us
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Quote:
Originally Posted by Booneandthebus
My brake lights are not working when the brakes are engaged. They work during the lamp check, so I figure it’s not a bulb issue. I cannot located a fuse for them. All other lights working. Any ideas where the brake light fuse might be or what the issue is? It’s a 2007 international. Thanks!
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You said they worked during the lamp test...how did you check them when you did the lamp test?
(to check the lights on my bus, someone would have to put their foot on the brake)
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01-18-2022, 10:19 PM
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#5
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Bus Crazy
Join Date: May 2007
Location: Whidbey Island, WA.
Posts: 1,109
Year: 1984
Coachwork: Blue Bird
Chassis: All American
Engine: 3208 na boat anchor
Rated Cap: 2
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I would suppose on a bus with air brakes that there would be a pressure switch in the brake application air circuit.
Best thing to do, if the bulbs and sockets are good, is to do voltage tests with an operational system (i.e. running bus). Take the voltage at a bulb socket. Apply the brakes and see if you get a voltage. If not, you might want to locate the brake light switch, where 'er that might be.
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01-19-2022, 06:42 AM
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#6
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Mini-Skoolie
Join Date: Sep 2021
Posts: 16
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Thanks for the reply’s!
There is air in the system. Brakes work fine.
I’m able to check the lights with a “lamp check” switch on my dash. It cycles through all of the lights to show which ones are working. I’m sure this is for the bus drivers before they go on route. Since all the brake lights light up during this, the bulbs are fine.
I’m thinking the brake sensor that was discussed is a prime suspect. Trying to locate it by the pedal. So if I do, what exactly should I be checking it for? Would it need to be replaced?
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01-19-2022, 09:18 AM
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#7
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Bus Crazy
Join Date: Apr 2019
Location: SW USA
Posts: 2,064
Year: 2003
Coachwork: IC / Amtran
Chassis: CE300
Engine: International T444e
Rated Cap: 23
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Yeah, if they're lighting up during that test (that's pretty cool), then the fuses, wiring, and bulbs are obviously all GTG.
Our bus has pressure switches right off the valve assembly the pedal is mounted to / actuates. In this picture (sorry for the quality) they're on the left-hand side, screwed into the ports behind the smaller set of green/orange air lines. You can see the wires coming off just as they're hidden by the steering column. Note yours could be reversed (right side), and they'd operate the same.
IF this was the source of your problem, you could test the pressure switches by pulling the plug off of them, and then measuring resistance across the terminals of the switch. Should be infinite resistance (open circuit) when brakes aren't pressed, and close to zero resistance (likely read a tiny resistance depending on your meter/range) when the brakes are pressed.
If they are working as they should, then you could move on to other tests. One of those two leads coming into the switch should read +12V or more.
__________________
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Our Build: Mr. Beefy
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04-12-2022, 02:14 PM
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#8
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Mini-Skoolie
Join Date: Sep 2021
Posts: 16
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Finally getting around to fixing this and not having much luck...
I replaced the air brake switches and no dice. But, I was finally able to figure out that I am blowing the fuse every time I hit the brakes. I'm thinking it's a ground issue somewhere, but I'm having trouble finding it.
The same lights work fine as running lights, it only blows the fuse when I press the brakes. Is a bad ground my most likely culprit? Any idea where I should be looking for one?
Thanks!
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04-12-2022, 05:07 PM
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#9
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Skoolie
Join Date: Aug 2021
Location: Santa Fe
Posts: 134
Year: 2007
Coachwork: Thomas
Chassis: 31 ft. HDX
Engine: CAT C7 250 hp
Rated Cap: 36,300 GVW
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You don't have a bad ground, you have a really good ground in the wrong place (a short circuit that blows the fuse).
Your brake light bulbs are most likely dual filament, one lower wattage filament for the running lights and a higher wattage filament for the brake lights.
The simplest thing to do is remove and inspect the bulbs.
You really need a wiring diagram to test this.
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04-12-2022, 05:39 PM
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#10
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Bus Crazy
Join Date: Jul 2021
Location: Southern Oregon
Posts: 1,607
Year: 1996
Coachwork: AmTran (Now Navistar)
Engine: DT444E (7.3L) International
Rated Cap: 31,800 pounds
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Quote:
Originally Posted by Booneandthebus
Finally getting around to fixing this and not having much luck...
I replaced the air brake switches and no dice. But, I was finally able to figure out that I am blowing the fuse every time I hit the brakes. I'm thinking it's a ground issue somewhere, but I'm having trouble finding it.
The same lights work fine as running lights, it only blows the fuse when I press the brakes. Is a bad ground my most likely culprit? Any idea where I should be looking for one?
Thanks!
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Short answer: NO
A "bad ground" isn't going to cause a fuse to blow. What you most likely have is a "short to ground" and it is somewhere between the brake switch and where the lamp test circuitry joins the wire to the brake lights.
Remove the fuse
Test the side of the fuse that gets power from the brake light switch - you should see battery voltage
Test the other side of the fuse holder from the fuse terminal to ground - You're looking to see if there is a short to ground.
This should help you get started on narrowing down where the problem is.
Also, it might be well worth the effort to try to find some schematics applicable to your bus. Perhaps on the inside of the outside electrical panel door??
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We've done so much, for so long, with so little, we now do the impossible, overnight, with nothing. US Marines -- 6531, 3521. . . .Ret ASE brakes & elect. Ret (auto and aviation mech). Extra Class HAM, NAUI/PADI OpenWater diver
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04-12-2022, 08:45 PM
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#11
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Bus Nut
Join Date: Dec 2021
Location: Iowa City, IA
Posts: 642
Year: 2006
Chassis: IC CE300 (PB105)
Engine: DT466e @245hp | Allison 3000PTS
Rated Cap: 66
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Quote:
Originally Posted by Booneandthebus
I replaced the air brake switches and no dice. But, I was finally able to figure out that I am blowing the fuse every time I hit the brakes.
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I would double check the wiring on that switch. You may have misconnected something or have a frayed wire that is shorting when the switch is activated
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