Steve P Posted August 30, 2023 Share Posted August 30, 2023 I have two of these hanging on the firewall, drivers side, seen when opening the generator hatch... what are they for? (I a.m stil chasing the issue with my cruise not cutting off when I hit the brakes.) Thanks for the help. I'm traveling and having cruise control cutoff sure would be nice! It's not safe the way it is. Link to comment Share on other sites More sharing options...
BradHend Posted August 30, 2023 Share Posted August 30, 2023 Even the main cruise switch won’t kill your cruise? Link to comment Share on other sites More sharing options...
Tom Cherry Posted August 30, 2023 Share Posted August 30, 2023 If you have TWO, then odds are they are the Pressure Transducers for your Air Gauges. They HAVE NOTHING to do with the Cruise... ALL they do is measure the pressure. BUT, if the PSI drops below 65 PSI, then BINGO...your rear brakes could LOCK ON....even while traveling. Assuming you have the VIP steering wheel, then the VIP controls should turn ON and OFF the cruise. I would read the manual. Most have the Cruise On/Off switch and the set and resume. If these functions are NOT working, then do NOT use the Cruise and trouble shoot. One SIMPLE thing is to pull the cowling from below the steering column. There are connectors there that connect the VIP outputs to the chassis harness. Plug and unplug and reseat them. There MAY also be a harness (with connectors) up under and above the generator (get to it with the Genny out and on the drivers side). These come loose....and you do the same. MOST of the VIP issues are loose connectors. BUT, past that, then you need to have it serviced. The "Clock Spring" has been know to wear out and needs to be replaced. Google that as well as look in our files... 1 Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted August 30, 2023 Share Posted August 30, 2023 2 hours ago, Steve P said: I'm traveling and having cruise control cutoff sure would be nice! It's not safe the way it is. For sure, ya really need that cruise to cut off properly. I doubt if I would even turn it on until it's fixed. Have you checked that your stoplights are working? If not take a look at those & come back. Link to comment Share on other sites More sharing options...
Tom Cherry Posted August 30, 2023 Share Posted August 30, 2023 3 hours ago, Steve P said: I have two of these hanging on the firewall, drivers side, seen when opening the generator hatch... what are they for? (I a.m stil chasing the issue with my cruise not cutting off when I hit the brakes.) Thanks for the help. I'm traveling and having cruise control cutoff sure would be nice! It's not safe the way it is. TIME OUT. I pulled the prints. You appear NOT to have a VIP wheel. Here is a PDF of the Cruise. You need to properly trouble shoot it and not drive when you can NOT disengage or kill the cruise. That would be very COSTLY and BAD. Here is also the 2009 Prints. Note, the Cruise says October 06 and higher...so this covers you. Look at the circuits and find out WHY the ON/OFF switch does not work. I added another print of the FRB which shows the relays. If one of the BRAKE SIGNAL relays is dead. Same THING. The suggestion to CHECK and see if you have BRAKE LIGHTS is doubly IMPORTANT. No Brake Lights...NO CRUISE CANCEL...if I understand the print. Start troubleshooting and do not allow this dangerous condition to continue...otherwise disable the cruise. YES, I tested a used full size Bronco with Cruise and it did NOT disengage. I smoked the tires and almost hit a car because of that. IT WAS NOT PRETTY.... Cruise Control 38071438.dwg.pdf 466778353_12VFRONTDISTRIBUTIONALLDIESELS(05)16622595.pdf Link to comment Share on other sites More sharing options...
Steve P Posted August 31, 2023 Author Share Posted August 31, 2023 11 hours ago, BradHend said: Even the main cruise switch won’t kill your cruise? The cancel cruise switch is on the side console (no smart wheel on Knight's, at least not that year). It works, but the delay in an emergency could be a costly difference. 1 Link to comment Share on other sites More sharing options...
Steve P Posted August 31, 2023 Author Share Posted August 31, 2023 (edited) @Tom Cherry My brake lights and toad lights are working fine after I replaced the trailer socket. Thanks for the prints. You are correct... I have no VIP/Smartwheel. I studied the prints on my phone. I have to admit circuit diagrams are not my strong suit... that said, I see several possibilities: the service brake treadle valve (which is what? Some kind of air pressure sensor that signals electrically when an air pressure drop occurs during braking? Supposedly on the firewall? ). I don't really understand the principles of how that works. I also see what I think is a fuse symbol in the circuit above the BRK SIG RLY, and the relay is shown on both prints, and I will swap the relay with another of like kind. And do a continuity check on the fuse with a VOM. Regarding the relay, I think this is the infamous Front Run Bay with it's G8VL-1A4T-R-L Omron relays that I can't find. Nor can I find a substitute. I'll go back to NAPA with the relay and the spec on the print. APPARENTLY, I'm over my head and subject to rapidly losing my mind... If I need a repair facility, I guess I better find a good Cummins Service Center. The one in Gaffney SC is already miles behind me. I'm in Winchester VA, with stops in Philadelphia, Syracuse NY, Stowe VT, Lavonia NH, and coastal ME up to Bar Harbor. Any recommendations, anyone? Thanks everyone for the insights so far! Edited August 31, 2023 by Steve P Correcting spelling Link to comment Share on other sites More sharing options...
Tom Cherry Posted August 31, 2023 Share Posted August 31, 2023 1 hour ago, Steve P said: @Tom Cherry My brake lights and toad lights are working fine after I replaced the trailer socket. Thanks for the prints. You are correct... I have no VIP/Smartwheel. I studied the prints on my phone. I have to admit circuit diagrams are not my strong suit... that said, I see several possibilities: the service brake treadle valve (which is what? Some kind of air pressure sensor that signals electrically when an air pressure drop occurs during braking? Supposedly on the firewall? ). I don't really understand the principles of how that works. I also see what I think is a fuse symbol in the circuit above the BRK SIG RLY, and the relay is shown on both prints, and I will swap the relay with another of like kind. And do a continuity check on the fuse with a VOM. Regarding the relay, I think this is the infamous Front Run Bay with it's G8VL-1A4T-R-L Omron relays that I can't find. Nor can I find a substitute. I'll go back to NAPA with the relay and the spec on the print. APPARENTLY, I'm over my head and subject to rapidly losing my mind... If I need a repair facility, I guess I better find a good Cummins Service Center. The one in Gaffney SC is already miles behind me. I'm in Winchester VA, with stops in Philadelphia, Syracuse NY, Stowe VT, Lavonia NH, and coastal ME up to Bar Harbor. Any recommendations, anyone? Thanks everyone for the insights so far! https://layingaround.com/g8vl1a4trldc12-g8vl-1a4t-rl-relay-automotive-spst-20a-12v-replacment-offered/ The other thing. Substitute a Bosch relay and rewire it to match the Omicron’s circuit. They are a SPST relay - 20 A. So use a 5 pin Bosch 20, 25 or 30. Doesn’t matter. Bases are on Amazon. That should work. Link to comment Share on other sites More sharing options...
DennisZ Posted August 31, 2023 Share Posted August 31, 2023 Make sure your brake lights are working properly, In had an issue with my cruise not going off with the brake, both of my brake pressure switches had gone bad. Link to comment Share on other sites More sharing options...
Steve P Posted August 31, 2023 Author Share Posted August 31, 2023 7 hours ago, DennisZ said: Make sure your brake lights are working properly, In had an issue with my cruise not going off with the brake, both of my brake pressure switches had gone bad. Thanks Dennis! My brake lights are fine. Im stil searching for the pressure switches... Link to comment Share on other sites More sharing options...
DennisZ Posted August 31, 2023 Share Posted August 31, 2023 Steve My pressure switches are mounted on the brake tredel valve mounted on the wall in the front bay above the generator. If your brake lights are working, it’s something else, the same switch closure that operates the brake lights disengages the cruise. Here’s some pictures of mine, before and after replacement. Link to comment Share on other sites More sharing options...
Steve P Posted August 31, 2023 Author Share Posted August 31, 2023 Thanks to the pics from Dennis, I found my brake switches... see below. However, it was my impression that one switch operated the brake lights and there other the cruise (I'm guessing the prints tell the story, so back to deciphering those, and looking for the infernal BRK SIG RLY.) Link to comment Share on other sites More sharing options...
DennisZ Posted August 31, 2023 Share Posted August 31, 2023 19 minutes ago, Steve P said: Thanks to the pics from Dennis, I found my brake switches... see below. However, it was my impression that one switch operated the brake lights and there other the cruise (I'm guessing the prints tell the story, so back to deciphering those, and looking for the infernal BRK SIG RLY.) Steve My pressure switches are mounted on the brake tredel valve mounted on the wall in the front bay above the generator. If your brake lights are working, it’s something else, the same switch closure that operates the brake lights disengages the cruise. The switches are for the primary and secondary air systems (fwd & Aft), the switches are wired in parallel, either one will operate the lights or disengage the cruise. It’s kind of a pain to change them, you have to remove the valve from the firewall to do it. They are in there VERY tight. I ws able to do it without disconnecting any of the air lines. Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted August 31, 2023 Share Posted August 31, 2023 22 minutes ago, Steve P said: However, it was my impression that one switch operated the brake lights and there other the cruise No, I don't believe that's the case. It's been stated here that they do the same job with each one backing up the other. Link to comment Share on other sites More sharing options...
DennisZ Posted August 31, 2023 Share Posted August 31, 2023 Ray is correct. The switches are for the primary and secondary air systems (fwd & Aft), the switches are wired in parallel, either one will operate the lights or disengage the cruise. It’s kind of a pain to change them, you have to remove the valve from the firewall to do it. They are in there VERY tight. I ws able to do it without disconnecting any of the air lines. Link to comment Share on other sites More sharing options...
Steve P Posted September 1, 2023 Author Share Posted September 1, 2023 I changed the BRK SIG RELAY in the front run bay this afternoon. We leave for Philly in the morning. I hope this solves the problem. It's not proper diagnosis, but it was cheap and easy. If it doesn't solve the problem, I'll have to figure out what else to test and how to isolate the problem. Link to comment Share on other sites More sharing options...
96 EVO Posted September 1, 2023 Share Posted September 1, 2023 Well, you know if it doesn't fix your problem, just don't use CC. Link to comment Share on other sites More sharing options...
Steve P Posted September 5, 2023 Author Share Posted September 5, 2023 @Tom Cherry My brake lights and toad lights are working fine after I replaced the trailer socket. Thanks for the prints. You are correct... I have no VIP/Smartwheel. I studied the prints on my phone. I have to admit circuit diagrams are not my strong suit... that said, I see several possibilities: the service brake treadle valve (which is what? Some kind of air pressure sensor that signals electrically when an air pressure drop occurs during braking? Supposedly on the firewall? ). I don't really understand the principles of how that works. I also see what I think is a fuse symbol in the circuit above the BRK SIG RLY, and the relay is shown on both prints, and I have swapped the relay with a new one of like kind. And did a continuity check on the fuse with a VOM. And still, cruise will not cancel. Is that a diode in the circuit diagram? What are the odds that it might be bad? APPARENTLY, I'm over my head and subject to rapidly losing my mind... If I need a repair facility, I guess I better find a good Cummins Service Center. The one in Gaffney SC is already miles behind me. I'm in Syracuse NY, then Stowe VT, Laconia NH, and coastal ME up to Bar Harbor. Any recommendations, anyone? Thanks everyone for the insights so far! Link to comment Share on other sites More sharing options...
Tom Cherry Posted September 5, 2023 Share Posted September 5, 2023 @Steve P & OTHERS Edited this based on new information and also a lot of phone time with Frank McElroy. First. You reported that you brake lights worked. Second...you have changed a relay. I am reposting the Cruise Print as it will be used and easier to see here. After Frank and I went over at least 10 different drawings... and then later on, I went through the entire 214 in the big file. We have concluded that only ONE relay should be the issue. BUT, I can't find a location as Monaco did not permanently mount it. It is NOT one of the ones of the FRB (relays 1 - 9 or 10). It is PROBABLY handing or dangling in the FRB. You HAVE to find this one relay before you make any progress. ON the print, in the lower right, it is called BRK SIG RLY. Not to be confused with other relays....one is a BRAKE SIG RLY. WHY, ask Monaco. If you have been using the SVC Brake one on the main board....this is not the BRK SIG RLY. Monaco would hang relays in sockets and write down the title, hand printed, with white ink. That is what you are looking for. There are a few ways to test... FIRST...Do you have a VOM? If not, then you might get one. You sound like you are advancing, so take the next step. Switch ON & Engine RUNNING….brake pedal NOT pushed. Pin 30 on the relay should be a GOOD GROUND (use VOM). Push Brake so treadle valve is engaged and brake lights ON….voltage on Pin 30. 5 minimum….maybe upwards of 12 VDC…. BUT....if NOT....then measure voltage to Pin 85 from Ground (it may be Pin 86, if Monaco reversed. ONE of these pins, with POWER ON, has to have 12 VDC...solid...or maybe a little higher like 12.5 which is chassis battery. NOW...focus on pin 86 (assuming Pin 85 has voltage) If there was voltage on Pin 86...then go to Pin 85. It doesn't matter. WHICHEVER pin has NO VOLTAGE....then with ignition ON, step on the brake. Here is where it gets TRICKY. FIND the DIODE in the circcuit. THe INCOMING wire MUST have a GROUND SIGNAL. That comes from the Brake Pedal and you said you have Brake Lights. NOW....put the relay back into it. Assuming you have a GOOD relay, then the OTHER SIDE of the diode or both sides should be grounded. IF BOTH are NOT ground....then you have a BAD DIODE. IF someone installed the DIODE backwards...and the incoming line, not the one to the relay, has a GROUND...you KNOW the Brake pedal is FINE.... That's it. There are a few other relays to find and swap out...but basically, this is the ONE that is SUPPOSED to go to the ECM. When that signal goes or is read by the ECM, the ECM disengages the cruise control. SO, let us know and we can try a few relay swaps...but the BRK SIG RLY has to be energizing when you PUSH the brake. If it don't, then there is a break in the circuit...probably the ground and probably the DIODE. Wish I could direct you to the exact spot....but Monaco "don't know" or was not tellin'.....and they have other relays, a BUNCH, on the prints...but only a few on the main board. Good Luck... Cruise Control 38071438.dwg.pdf Link to comment Share on other sites More sharing options...
Steve P Posted September 5, 2023 Author Share Posted September 5, 2023 Yes, all the cruise functions work on the driver side console, no exceptions. l think I can do all that you've described... but it will have to be on a cooler day than today (unseasonably hot day in NY). Maybe Friday of no rain. Front of the MH is facing south for the next week baking in the sun. One thing about ordinary brake lights: they seem only to work when the ignition is on (as expected) AND the air is around 65+ lbs guessing by the analog gauge. Second weird thing: when applying the brakes, the center marker light on the rear flashes first, then goes out, and as you continue to apply the brakes, all the lights then light including that one. Below 65ish, no brake lights. Is that due to treadle valve? So, Step one: VOM on a VDC setting, use leads to see which pin, 85 or 86 has 12V (measure between pin and known ground). Step two: VOM on ohms setting, while assistant presses brake, use leads to measure for ground on other pin. I don't really know what you mean... where to put 2nd lead and how to find diode to measure at both sides. Also, measurements at treadle switch may be useful, so I'm looking at wires for labels. Thanks in advance! Link to comment Share on other sites More sharing options...
DennisZ Posted September 6, 2023 Share Posted September 6, 2023 I don’t know why you would have to have over 65 PSI to make your brake lights work, that is not correct, the brake pressure switches should activate in the range of 3 to 5 psi. You sill may be chasing bad brake switches. If you disconnect the electrical connector between the switch and the chassis, you should be able to check them for proper operation, only 2 of the 3 wires from the switch are used, you can look at the chassis mating connector to see which wires are used. Are you able to turn on your cruise control with the engine running and the transmission in neutral to get your engine to a fast idle? If you can, with the switches disconnected from the chassis wiring, place a jumper in place of the switch, your brake lights should come on and the cruise should disengage. Link to comment Share on other sites More sharing options...
Tom Cherry Posted September 6, 2023 Share Posted September 6, 2023 12 hours ago, DennisZ said: I don’t know why you would have to have over 65 PSI to make your brake lights work, that is not correct, the brake pressure switches should activate in the range of 3 to 5 psi. You sill may be chasing bad brake switches. If you disconnect the electrical connector between the switch and the chassis, you should be able to check them for proper operation, only 2 of the 3 wires from the switch are used, you can look at the chassis mating connector to see which wires are used. Are you able to turn on your cruise control with the engine running and the transmission in neutral to get your engine to a fast idle? If you can, with the switches disconnected from the chassis wiring, place a jumper in place of the switch, your brake lights should come on and the cruise should disengage. First….the OP does NOT have a VIP wheel. He has no “fast idle” option….or that is what I he said earlier. Second…I AM concerned about the 65 PSI. If he means that when driving he barely has 65 PSI, then that is an issue…a MAJOR one. BUT…the real test…and I am changing my “recommendations”. TEST with the engine running and full air pressure…which should be between 110 & 120 PSI. Using the brakes for testing without running the engine, will, drain them… The “sequence of the brake lights” is somewhat convoluted. His ECM has control of “brake applied disengagement”. There is NO DIRECT switch or wire to jumper…if he did such, it could be dangerous and possibly damaging the ECM…. So, I wouldn’t do that. The ONLY way to really test the lights for functional purposes is to DRIVE….with someone behind you and two cells. My “recollection” is that the exhaust brake (since there is a VGT BRK SIG relay will bring on the Liddy (center…named by the underling engineers in the Fed DOT as there were no tests or studies done on the “merits of every vehicle having a third brake light…it was a pet lroject ofmthe head of DOT, Elizabeth “Liddy” Dole)…light….then, if you apply the service brake, I think all come on. That is why there is a special relay for the trailer brake lights…. Bottom line…all is working as it should and the individual switches (he has 3 on a console) work fine. He HAS brake lights (I would drive just to see and play with), so if THEY are working, then all those convoluted and various named relays and the treadle switch is work. What is NOT happening is that Pin 5 (incoming) to the ECM is not working…and that is what the BRK SIG RLY must supply…so…the procedures outline previously will test that. If the relay is fine…and a signal is coming…then big time trouble shooting to go to the ECM and then see IF the signal THERE (pin 5) is working. Then…OPPS….now what. It MAY BE….highly unlikely…that the parameters in the ECM were set wrong. It will take a really sharp Cummins tech and the Insight software to analyze and decide. BUT…we have one of the best in the country here and he has, as a courtesy, looked at printout and diagnosed and such. So, if it comes to that…there is a plan. I was late for an appointment yesterday…will edit the post… Switch ON & Engine RUNNING….brake pedal NOT pushed. Pin 30 on the relay should be a GOOD GROUND (use VOM). Push Brake so treadle valve is engaged and brake lights ON….voltage on Pin 30. 5 minimum….maybe upwards of 12 VDC…. Link to comment Share on other sites More sharing options...
Tom Cherry Posted September 6, 2023 Share Posted September 6, 2023 15 hours ago, DennisZ said: I don’t know why you would have to have over 65 PSI to make your brake lights work, that is not correct, the brake pressure switches should activate in the range of 3 to 5 psi. You sill may be chasing bad brake switches. If you disconnect the electrical connector between the switch and the chassis, you should be able to check them for proper operation, only 2 of the 3 wires from the switch are used, you can look at the chassis mating connector to see which wires are used. Are you able to turn on your cruise control with the engine running and the transmission in neutral to get your engine to a fast idle? If you can, with the switches disconnected from the chassis wiring, place a jumper in place of the switch, your brake lights should come on and the cruise should disengage. @DennisZ & @Steve P Steve...Frank and I spent an hour on this. I have appointements, but will post an update tonight or tomorrow... Dennis has some good info. I will put a step by step procedure that will address the issue as to why or why NOT you may have brake lights below 65ish. Steve, what we need from you is pictures of your Front Run and Rear Run bay. Look on page 177 and shoot a picture of where R2 in on the front. Get a close up of R2 relay so we know the type. Likewise, take a picture of the back relays... Are they the exact same relays? IF SO...then swapping under certain conditions will make trouble shooting easier. On the FRB, take a picture of the two Diodes...the one to the left of R2. Also your air pressure gage, either one, on the dash. Picture will be great and make my explanation easier.... That's it... Link to comment Share on other sites More sharing options...
Steve P Posted September 6, 2023 Author Share Posted September 6, 2023 (edited) Front Run Bay Edited September 6, 2023 by Steve P Add photo Link to comment Share on other sites More sharing options...
Steve P Posted September 7, 2023 Author Share Posted September 7, 2023 (edited) Rear Run Bay pics were hi-res and plainly visible until they were uploaded... I will take better ones tomorrow Edited September 7, 2023 by Steve P Link to comment Share on other sites More sharing options...
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