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Brake Lights not working


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2003 HR Endeavor... 40PST  

My brake lights are not lighting up when I push the brake pedal, they will light up when I use the manual lever for the trailer/toad.  Sometimes when I step on the brake pedal just right I can get them to blink momentarily,... so I think the switch that the pedal/air system activates has gone bad.   

Now the question... where is it??  Here is a photo, up front by the generator that may or may not be the switch.... and there are two switches there.... is it one or both of them that turn on the brake lights?? 

And if it is one of those switches, anyone have a part number so I can get one (or more) coming?

BrakeSwitches.jpg

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On 10/5/2022 at 12:32 PM, Cubflyer said:

My brake lights are not lighting up when I push the brake pedal, they will light up when I use the manual lever for the trailer/toad.  Sometimes when I step on the brake pedal just right I can get them to blink momentarily,... so I think the switch that the pedal/air system activates has gone bad.   

Anyone know the part number of these switches??BrakeSwitches.thumb.jpg.62baf29705b43a8e3f6b8968d29db852.jpg

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I just went thru the same issue a couple of months ago. Those switches are difficult to source, I ended up replacing mine with readily available brake switches as used in commercial applications, I got mine at Napa (P/N MBI BE13250) for about $37 each. Here is a picture of my switches installed. The original switches take a 1” wrench to remove and a lot of torque to break loose, I had to remove my treadle valve from the firewall to change the switches, I had enough length on my air lines so I didn’t have to disconnect them.

Dennis

0C5C0D6B-4179-41C9-A91C-A2CC5888EFB5.jpeg

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58 minutes ago, DennisZ said:

readily available brake switches as used in commercial applications, I got mine at Napa (P/N MBI BE13250) for about $37 each

Dennis,

Thanks for the info and the photo.  I see that your new switches have two terminals.  The switches I have three wires coming out of them...., red-black-blue. 

Is one of the three wire not used??  At first look mine all seem to be connected, but I have not pulled things out....

Ken

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Ken

Only 2 of the wires are used, the NO contacts, if your existing switches have enough length, you can cut off the wires and put on a couple of lugs for the new switches. You can see which wires are used, the harness on the coach that they plug into should only have 2 wires on it.

Dennis

6 hours ago, Cubflyer said:

Dennis,

Thanks for the info and the photo.  I see that your new switches have two terminals.  The switches I have three wires coming out of them...., red-black-blue. 

Is one of the three wire not used??  At first look mine all seem to be connected, but I have not pulled things out....

Ken

 

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3 hours ago, DennisZ said:

You can see which wires are used, the harness on the coach that they plug into should only have 2 wires on it.

Guess I need to go chasing some wires! Thanks, I will next time I get to my coach.-Ken

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Two suggestions.

First.  You need to determine WHICH switch is NOT functioning.  You are going to have to pull the switch anyway. Pull one off.  Go to a truck parts shop.  Take then the switch.  It looks like there is a tag or product ID.  90% of the time, a good shop will know what it is.  Then they can replace it.  

I would NOT start  messing around and try a 2 wire switch without doing a lot of circuit testing.  There is a YouTube video on how to make up a test rig to see what is going on.  That IS a method….and once you figure out which switch is NOT working….or test them…..then you should easily see which one is defective.

SECOND.  Here is a POSSIBLE replacement.  What is UNKNOWN is WHY a there was a 3rd wire….and IF it is used somewhere else.  See the above and unless you have the Monaco schematic, you are at risk of making thing worse.  THIS HAS HAPPENED reversing or modifying has made a simple job now a tech nightmare.

here is, most likely, your switch.

https://www.waytekwire.com/item/76218/Nason-LM-2C-70R-WLAT-Rising-Low-Pressure-Switch-/

i would go to the NASON sight and look for a non adjustable high/low 3 wire switch.  If yours has the small adjustment screw, it is probably the one above.  But if it does not have an adjustment, then odds are, NASON makes a non adjustable one…..but you need to pull the switch.

if you really want to know, look at this YOUTUBE.  USE THREE NEEDLES OR STRAIGHT PINS and puncture the wires and do your test. You will have to rest each one to find the bad one and also test the new one.  Who knows, maybe Monaco couldn’t get the two wire switches….or the DID have need for all 3.

Good Luck

 

 

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Was late for an appointment. Chuck makes a good point.  Don’t know your trouble shooting skills. But I would recommend this.

USE 6 needles or pins for the wires.  You can put a dot of silicone on the holes…Go to the NASON site and check the tech spec for the switch I found or see if they have a Non Adjustable Low/High switch.

This is a SPDT switch.  ODDS ARE…. The RED is the output.  So, then, say BLACK, is the low or below 60/70 PSI signal.  Then the Blue has to be the HIGH.  So when pressure is low….red and say BLACK have a circuit.  Conversely when you have high pressure, then Blue and Red will make a circuit.

With the MH running and all aired up.    Turn OFF the ignition.  The pressure switch will work without any leads hooked up.  Check the circuits.  Red (assuming common or output) to the other two.  Do that for each switch.  Then have someone hold on or apply the brakes.  Which switch worked….as in making the HIGH circuit.

Drain off all the air tanks.  Good to do anyway.  NOW repeat the test.  Then have someone hold on the brakes…..then see what the switch is doing.

I don’t know which side of the brakes the switch is on.  Others probably do and can assist.  But…. Assuming that the pressure switches are sending A LOW (no or below say 60/70, then you would expect continuity or closure.  With air above the 60/70 set point, you would a circuit or closing on the other side.

IF you can find the “magic point” where the lights work…then find that and test the continuity.

Good Luck

 

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1 hour ago, Chuck B 2004 Windsor said:

I am Not a big utube fan.  Unless the video is brand, make, and model specific, you might be sent down a dark rabbit hole that leaves you stranded doing more harm than good.  JMHO.

Don’t argue that. But this one is OK for how to setup a test rig to trouble shooting a circuit.  In this case, if the OP uses pins instead of having spliced in test points, it is a good visual  reference. In addition, my specific recommendations were to do continuity only and not do any voltage measurement or tests to ground or such.

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On my coach, both switches were bad, maybe one a lot earlier than the other, but they are redundant, so if they both go out, no brake lights. My 1st clue that I had an issue is when my cruise wouldn’t disengage with the brake switch. 

Both switches had similar failure modes, if the brakes were applied slowly, they wouldn’t work, but if I pressed them very aggressively, they would work as well as disengage the cruise.

Edited by DennisZ
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4 minutes ago, DennisZ said:

On my coach, both switches were bad, maybe one a lot earlier than the other, but they are redundant, so if they both go out, no brake lights. My 1st clue that I had an issue is when my cruise wouldn’t disengage with the brake switch. 

Dennis,

That pretty much sums up my failure mode, my cruise would not disconnect very reliably with the foot pedal brake, but would always with the Exh brake application, and now the tail lights (brake lights) do not light up (although they will blink sometimes on first application). 

This is good info! I was planning on replacing both switches, if those switches were actually what controlled the brake lights, which it seems that, yes, they do.... 

Guess I just need to bite the bullet, reach up in there (PITA) and take them out, source a replacement switch and get it done!

Thanks !

Ken

 

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I couldn’t get mine out without removing the treadle valve from the firewall, it’s not to difficult, but makes replacing the switches possible (BTW, it’s a 2 man job, 1 inside and 1 outside) I pulled the dash out so we could get to the nuts easier.

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Dennis.... Oh this just keeps getting better all the time!  I hoped I could just get my genny access door out of the way so I could at least reach straight up in there. Rather than the contortions that I had to do just to get the photo... now it's sounding like even more to get them off...!    Ken

 

2 hours ago, Tom Cherry said:

if the OP uses pins instead of having spliced in test points, it is a good visual  reference.

Tom,

While I appreciate the advise on how to test, etc.... in this case, testing will be almost as hard to do as removal.  I'm old and squeezing up in there to probe wires is not happening...

Ken

Edited by Cubflyer
add r in hard
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On 10/11/2022 at 3:31 PM, Cubflyer said:

Dennis.... Oh this just keeps getting better all the time!  I hoped I could just get my genny access door out of the way so I could at least reach straight up in there. Rather than the contortions that I had to do just to get the photo... now it's sounding like even more to get them off...!    Ken

 

Tom,

While I appreciate the advise on how to test, etc.... in this case, testing will be almost as hard to do as removal.  I'm old and squeezing up in there to probe wires is not happening...

Ken

I STARTED to merge these two.  BUT, didn't want to as the switches may be different.  I fully appreciate your contortionists skills as I can't even do something ONCE, as I usedtacoulda.....  OK....read the above.  

Your situation MIGHT be different.  BUT, if you dropped or dumped the air in all your tanks, then tapped the brakes a few times just to be sure, You MIGHT pull out one switch.  OR you might communicate with @Capt Mikeusing the PM option.  You need an exact PN for your replacement switch.  The ONLY way to be sure is to pull one of them....or USE a flexible fisheye camera on your phone or tablet.  Amazon sells them.  They are GREAT.  They hook up like a "Router" and you wifi with them.  Then you use them to inspect and can do Screen Shots and such.  

Just passing this along....  I searched the Parts List.  Here is the Parking Brake Switch.  YES, you don't need that....but here is a list of vendors for Nason.  BUT, you will NEED the Switch Number. CaptainMike says it is SM-1C-5R/WP205.  I would verify that....or find your PN.  Here are the Vendors that are listed for Nason.

ORDER from Distributors Below DIRECT
Cross Company 866-219-8217 - GRUMPY FOLKS!
Sunsource 800-228-5800
Flow Dynamics 205-581-1200
Hydraulic Energy Products 800-800-3471
Fluid Power Equipment Co., 877-471-8999
Hydraulic Controls in Phoenix 602-278-6088 or 510-658-8300
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On 10/10/2022 at 7:32 AM, DennisZ said:

I just went thru the same issue a couple of months ago. Those switches are difficult to source, I ended up replacing mine with readily available brake switches as used in commercial applications, I got mine at Napa (P/N MBI BE13250) for about $37 each. Here is a picture of my switches installed. The original switches take a 1” wrench to remove and a lot of torque to break loose, I had to remove my treadle valve from the firewall to change the switches, I had enough length on my air lines so I didn’t have to disconnect them.

Dennis

0C5C0D6B-4179-41C9-A91C-A2CC5888EFB5.jpeg

Dennis,

there is a parallel thread going and probably should have been merged.  We do NOT have any Parts List information on the Brake Light Switches.  So, along those lines as well as trying to piece together some logic, If you or OTHERS, can fill in a few details, it would be beneficial to the group.

The switch you installed is a Haldex….and a common one.  Looking at the specs, it operates or actuates and closed the contacts at 3 + PSI.  Do you still have the OEM switches or the OEM PN so that then actuation pressure or ON/Off can be verified.  That would be great info for the parts list.

Second, what I can’t understand is what there are two switches.  Did you trace the circuit or have a print and can explain WHY two are needed.  One theory, and just that, one is a “Brake Light” ON circuit,  the other is a Cruise Control Cancel circuit. Again, just plain curiosity and that is how we all learn.

I can’t understand WHY the 3 wire switch in the original topic has a different circuit from that and why the LOW/HIGH switch, on both, are needed and what the functions are.

Any insight from you or others is appreciated.

Please, if you have the OEM a switch data, PM @Frank McElroywith that as well as the Haldex number.

Thanks, 

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Tom

The original switches have very similar pressure specs, I believe they were 4 +1, -0 to actuate. I don’t have the switches any longer, but I did verify the pressure specs of them before I started to find a replacement. The original switch is a Nason SM-1C-5R/WP205, see the attachment for the P/N specs. The switch I used is a BE13250, it is rated as a 3 to 5 psi actuation.

The switches are a backup of each other, they are wired in parallel, guess it must be some kind of DOT regulation for vehicles of our weight, if you look at air diagrams for OTR trucks, they also have 2 switches, unlike our passenger vehicles. The 3rd wire on the switch is not used, the vehicle side only has 2 of the wires in the plug, also verified on the chassis schematic.

Hope this all helps Tom, let me know if you need more info.

D0E9E69D-C364-41ED-97FB-441780A89E17.png

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Out of curiosity, I looked at my switches and I have 4 of them. Each 2 are the same and the reason for duplication is to keep the lights and cruise disconnect working when one of the air brake systems quits. One pair is NC (cruise), the other NO for brake lights. All rated at 3-5 psi. So I can see how the 2 three-wire switches would do the same and how they can be replaced with a use of more available 2 wire switches in a pinch. 

20221018_160136.jpg

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What I am saying is that if the problem is with brake lights not working and the correct 3 wire switch is unavailable, it could be worked around with a cheap $10 two wire NO switch just to keep going.

Edited by Ivan K
Typo
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2 hours ago, DennisZ said:

Tom

The original switches have very similar pressure specs, I believe they were 4 +1, -0 to actuate. I don’t have the switches any longer, but I did verify the pressure specs of them before I started to find a replacement. The original switch is a Nason SM-1C-5R/WP205, see the attachment for the P/N specs. The switch I used is a BE13250, it is rated as a 3 to 5 psi actuation.

The switches are a backup of each other, they are wired in parallel, guess it must be some kind of DOT regulation for vehicles of our weight, if you look at air diagrams for OTR trucks, they also have 2 switches, unlike our passenger vehicles. The 3rd wire on the switch is not used, the vehicle side only has 2 of the wires in the plug, also verified on the chassis schematic.

Hope this all helps Tom, let me know if you need more info.

D0E9E69D-C364-41ED-97FB-441780A89E17.png

On air brake system, the front brakes are supplied air from the secondary air tank and the drive and tag axles from the primary air tank through the service brake valves.  That's why you have two separate brake light pressure switches.  If either the primary or secondary air system should fail you would still have rear brake lights.

On some Monaco model coaches, one of the wires from the normally closed circuit was used to cancel the cruise control.  I've seen wiring diagrams where even though the coach has two 3 wire pressure sensors only the normally open switch wires are used and the NC wires aren't used on either switch. So, if you replace a 3 wire pressure switch with a 2 wire NO switch, you need to be sure that the third wire isn't being used on your coach.

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On 10/5/2022 at 1:32 PM, Cubflyer said:

2003 HR Endeavor... 40PST  

My brake lights are not lighting up when I push the brake pedal, they will light up when I use the manual lever for the trailer/toad.  Sometimes when I step on the brake pedal just right I can get them to blink momentarily,... so I think the switch that the pedal/air system activates has gone bad.   

Now the question... where is it??  Here is a photo, up front by the generator that may or may not be the switch.... and there are two switches there.... is it one or both of them that turn on the brake lights?? 

And if it is one of those switches, anyone have a part number so I can get one (or more) coming?

BrakeSwitches.jpg

Ken, for the brake lights not to work BOTH air pressure switches would have had to fail.  On a wiring diagram I have for a 2006 Endeavor, both of these pressure switches feed a Bosch relay called brake relay.  I'm not sure where you would find this relay but it should be very close to the trailer brake relay.  Either of these relays will turn on the brake lights.  Have you already verified that the brake relay is good?

image.thumb.png.d971a7efc880059ee927487cab046f31.png

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