chucknewman Report post Posted May 23, 2010 We have a '98 Safari with CAT 3126B and PacBrake. Everything works as designed, but I will be making some modifications on how the PacBrake is controlled. I have noticed many (not necessarily all) Safaris built by Monaco after about 2002 are wired wherein the stoplights come on when the PacBrake is activated (PB dash switch on and throttle not depressed). My question is twofold: 1. I don't think Monaco haphazardly builds one coach that PacBrake activates stop lights, and the next coach off the line does not activate the stoplights. Does anyone know their official rationale behind one technique vs the other? 2. Here, I'm looking for everyone's personal opinion on the subject of either exhaust brake or engine brake being in operation and activating the stoplights. Or not. Particularly in different scenarios -- downhill, flat and level, city traffic, etc. What has been your experience? Please add your comments concerning any liability or safety issues in traffic collisions you have been involved with. Thanks. Share this post Link to post Share on other sites
wolfe10 Report post Posted May 23, 2010 Chuck, A good question-- and IMO no clear-cut answer. When I would WANT the brake light to illuminate when the exhaust brake is activated: When coming to a stop. When I would NOT WANT the brake light to illuminate when the exhaust brake is activated: When descending long grades with exhaust brake on but not slowing down (i.e. exhaust brake holding my speed in equilibrium). If (and I do not) one chooses to leave the exhaust brake switch on in rolling hills-- one would NOT want the brake lights to come on on every downgrade. Last summer we followed a coach wired with brake lights on with exhaust brake on and they left the exhaust brake switch on. Every time they crested a small hill and started down, their exhaust brake and light came on. WOW-- I could never tell if there was a cow in the road right in front of the lead coach and we were coming to a panic stop or if we were just still cruising at 60 MPH and his throttle happened to close. Repeat 75+ times that day! Our coach was wired such that the brake light does NOT come on with the exhaust brake. To get around no brake light when coming to a stop-- I step a minimum of very lightly on the service brake while stopping. Actually service brake application is needed anyway most times coming to a stop. Your mileage may vary! Brett Share this post Link to post Share on other sites
chucknewman Report post Posted May 23, 2010 Thanks Brett, I've designed a system for my coach that will accommodate different driving conditions. And I particularly agree with the "rolling hills" scenario. You clarified an issue I was pondering during your situation in commute traffic across Houston with the PacBrake on. More opinions/comments please. Particularly on legal issues of stopping/slowing notification. Share this post Link to post Share on other sites
shields Report post Posted May 23, 2010 I have a Monaco Dynasty wired to illuminate the brake lights when the PacBrake is activated. Since the purpose of the brake lights is to warn drivers behind that you are slowing -- and potentially slowing suddenly -- the PacBrake sends out "false alarms" because it does not slow the coach suddenly. In my estimation, a better arrangement would be to just have the brake lights illuminate when the service brakes are used. Good luck. Tim Shields Share this post Link to post Share on other sites
Guest BillAdams Report post Posted May 23, 2010 As a point of opinion only, I have never understood why a pac-brake would activate anyone's brake lights. Have you ever seen a truck heading down a hill with their Jake Brakes screaming have the brake lights lit? Of course not. When they have to slow more than their Jake is able to handle they use their brakes and the tail lights come on to let those behind them know that they are now intentionally slowing their vehicles. If the tail lights were on as they came down a hill and something happened in front of them that required more immediate braking the vehicles behind would never know that anything different was going on and could well pile into the rear of the truck having no idea what the heck just happened. Share this post Link to post Share on other sites
garykd Report post Posted May 24, 2010 My coach is wired so the brake lights come on only when the service brake pedal is depressed. This is the way I want it. Share this post Link to post Share on other sites
tbutler Report post Posted May 24, 2010 I'll be a counter to most opinions here. Our coach is wired to activate the brake lights when the engine brake is activated. Now, I don't drive with the brake armed at all times. I'll use it when I need it, including long grades. As I see it, activating the brake lights lets the following traffic know that I'm not traveling at the prevailing highway speed but am traveling slower than the faster traffic. Similar to engaging the emergency flashers when my speed drops below 40 MPH on a long grade up a mountain. If I employ the service brakes, then brake lights on the toad are activated. They are not activated with the engine brake. This two stage brake light activity provides the extra warning when we are slowing more rapidly. In my experience truckers know what is going on. When they see my brake lights come on, they pull out into the passing lane if they want to free wheel it on down the grade. For traffic going 70 MPH, those brake lights let them know they should hit the passing lane well before they are right behind me. I really don't see a problem with a brake light that indicates any retarding of the forward progress of the vehicle. A brake is a brake and any application of such should be noted in some way by following drivers. Share this post Link to post Share on other sites
sundancev Report post Posted September 19, 2014 Brett: I was looking through some old forum items and came across this issue. We have a2004 Fleetwood Providence with a 350 HP Cummins ISC engine. My wife was following me up and down a mountain recently in our toad and mentioned that I was constantly using the brake and wondered why. I distinctly remember not using the brake until I was actually ready to stop. I then had her follow me on a straight level road where I also had the exhaust brake activated and as I slowed down for traffic ask her by telephone if she was seeing brake lights. She answered affirmatively and I realized that my exhaust brake did in fact activate the brake lights and could understand the frustration from drivers behind me for many thousands of miles as I slowed down each time the brake lights would come on. So, I want to deactivate my exhaust brake lights and did not see in this thread any suggestions as to how to actually make that happen. Would you know by chance how such a thing is easily accomplished? Having asked you, I also realize you cannot be an expert on every motor home built and thank you for whatever response you may provide. sundancev (Paul) Share this post Link to post Share on other sites
wolfe10 Report post Posted September 19, 2014 Paul, Contact your chassis maker. They are the ones who determine how the brake lights are wired. Share this post Link to post Share on other sites
dickandlois Report post Posted September 19, 2014 Hi Paul, Brett is correct. I think that there is a relay in the circuit that activates when the exhaust brake is active. Fleetwood will be able to inform you of the relay location if you wish to deactivate that feature. Just make sure that it is done in a way that doesn't also turn off the brake lights or affect the cruse control circuit when you depress the brake pedal!Rich. Share this post Link to post Share on other sites
sundancev Report post Posted September 20, 2014 Thanks Brett and Rich for your suggestions. I did contact Freightliner in Gaffney. Their response was brake lights are essential part of safety and they believe the brake lights should come on when Engine Brake was in fact in effect. So, not sure what to do now. As discussed in this forum, often the issues of safety as determined by Freightliner are not the same at other manufacturers for good reason (frusterated folks behind us.) The only way around it seems to be use manually select lower gears and use the exhaust brake option minimally. Paul Share this post Link to post Share on other sites
bizsmith@yahoo.com Report post Posted September 21, 2014 I would agree with the opinions that the stop lights should NOT come on with the pac brake. With a very light pressure on the service brake pedal, YOU are in control of when the stop lights come on. Share this post Link to post Share on other sites
desertdeals69 Report post Posted September 22, 2014 The wiring harnesses are manufactured with the stop light circuit activated when the exhaust brake circuit is on. The reason for this is that the vehicle is slowing down and it doesn't know if it is the service brake or the exhaust or Jake brake. How it is wired is up to the coach builder. I am familiar with Sinclair Technologies who manufacture chassis harnesses for most of the RV chassis and a lot of school buses. Share this post Link to post Share on other sites
