Mike in Va Posted April 7, 2023 Share Posted April 7, 2023 I have a 2001 HR Ambassador with the 5.9 cummins. I think the vacuum pump has stopped working. I was hoping someone could give me an idea where the pump is located and the fuse that its connected to. I see the vacuum storage bulb is in the front compartment . It has one black hose coming out of the bottom of the bulb and going down under the coach towards the passenger side of the generator. It's raining today but I was want to get out tomorrow and start looking for it. Thanks for the help. Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted April 7, 2023 Share Posted April 7, 2023 Mine is on the firewall above the generator next to the bulb or ball you mentioned. The fuse should be in the elect compartment left front. My pump looks like this. A few early Monacos had a venturi vacuum generator which I believe would be contained in a small box Link to comment Share on other sites More sharing options...
Solution donbouv22 Posted April 8, 2023 Solution Share Posted April 8, 2023 The vacuum pump should be real close to that bulb. I had to replace mine awhile ago, I had no heat or defrost up front, that fixed it. Good luck! Link to comment Share on other sites More sharing options...
Mike in Va Posted April 10, 2023 Author Share Posted April 10, 2023 Hey Ray I can't seem to locate the pump that is included in your response. I do have a small black metal box above the vacuum bulb. The rubber tube came out of the bulb into the box and there is a 3/8 red rubber hose that comes out and go back towards the rear of the coach. Could this little box contain the venturi vacuum generator you spoke of? Link to comment Share on other sites More sharing options...
Ivan K Posted April 10, 2023 Share Posted April 10, 2023 So the box is your air operated vacuum pump. It got a solenoid valve inside and a vacuum switch. It just might need cleaning, you might be able to save it. Link to comment Share on other sites More sharing options...
Mike in Va Posted April 10, 2023 Author Share Posted April 10, 2023 Thanks, I'll try to take it apart and clean it. Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted April 10, 2023 Share Posted April 10, 2023 38 minutes ago, Mike in Va said: Hey Ray I can't seem to locate the pump that is included in your response. I do have a small black metal box above the vacuum bulb. The rubber tube came out of the bulb into the box and there is a 3/8 red rubber hose that comes out and go back towards the rear of the coach. Could this little box contain the venturi vacuum generator you spoke of? Mike, that's more than likely it. There's not much to go bad in it. Like Ivan said clean the venturi area and make sure the hose that is going towards the rear has air coming into the box. That air hose is what I would check first. The idea is a slight amount of air passes a venturi creating a suction/vacuum. Your system is pretty rare, I talked to a 40 yr RV tech that had never heard of such a thing. He didn't seem to believe me so I had to google one to show him. If you can't get yours to work or don't want to mess with it, some owners install the little 12v pump. They are easy to find by searching Ford or Ram diesel vacuum pump, approx $100. Link to comment Share on other sites More sharing options...
Mike in Va Posted April 10, 2023 Author Share Posted April 10, 2023 Ray the red hose going down and towards the back of the coach is wrapped in black plastic and is included in a 6 in ball of wires. My question is where does the red tube go? Is it hooked to my front air tank? Link to comment Share on other sites More sharing options...
Ivan K Posted April 10, 2023 Share Posted April 10, 2023 It should be branching off from PPV on front tank, likely same PPV that supplies the horn (blue in my case) and whatever other accessory you might have. Link to comment Share on other sites More sharing options...
Mike in Va Posted April 10, 2023 Author Share Posted April 10, 2023 I was able to find my manual and it show a red tube coming off to a vacuum generator. I've been looking for a pump. Thanks so much. I' m going to try and clean it out. Do you still have this system on your mh? Don't want to change the whole system unless I really have to. Link to comment Share on other sites More sharing options...
Ivan K Posted April 10, 2023 Share Posted April 10, 2023 I have the same thing, still working fine. Did not work when we bought it and all it needed was to clean it. I don't remember the details but I think it just wasn't sealing right. Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted April 11, 2023 Share Posted April 11, 2023 I have the little 12v pump for vacuum, which in my opinion is far more trouble-prone than your vacuum generator. An advantage of the 12v pump is it's easily replaced, and cheap. Link to comment Share on other sites More sharing options...
Dr4Film Posted April 11, 2023 Share Posted April 11, 2023 (edited) Here is a photo of the air vacumn pump you are looking for. It's the black rectangle box on the right of the vacuum reservoir. Edited April 11, 2023 by Dr4Film Link to comment Share on other sites More sharing options...
Mike in Va Posted April 11, 2023 Author Share Posted April 11, 2023 Your picture show what mine looks like. I had a picture and wanted to post it but not sure how to attach it. Thanks for every one"s help. Link to comment Share on other sites More sharing options...
quick_tox Posted April 12, 2023 Share Posted April 12, 2023 I have the same “pitot tube” vacuum pump that works off an air line. I took it apart and put a tip cleaner down the pitot tube, worked once, then stopped working again. Through trial and error I discovered that a rap on the pump with a screwdriver handle when the engine was running would work, vacuum door on the dash a/c would immediately work and continue to work until I restarted the engine. This workaround went on for several years. Last year I changed out my air governor due to excessive time to pump up my air bags. This fixed the slow airbag problem and also fixed the vacuum pump problem. You need to find out what your air pressure is. Link to comment Share on other sites More sharing options...
Mike in Va Posted April 12, 2023 Author Share Posted April 12, 2023 Robert, I took the vacuum generator off and cleaned it good. There was a little bit of stuff inside it and the electric solenoid worked well also. I checked the air pressure before I took it off and had plenty of air pressure. I do have a problem with 12 volts going to the heater switch. It's never worked since I've owned the mh. The fan wouldn't come on and the meter shows no voltage getting to the heater control switches. I have checked every fuse and switch labeled air cond or heater and haven't had any luck finding the bad one. The air compressor is locked up so I up plugged it. I'm not interested in getting the air conditioner to work just the heater to work. Any help would be appreciated. Link to comment Share on other sites More sharing options...
Robert92867 Posted April 14, 2023 Share Posted April 14, 2023 Just got home. I do have the 2001 Ambassador schematics, let me see if I can trace the heater sol. controls... Link to comment Share on other sites More sharing options...
Robert92867 Posted April 14, 2023 Share Posted April 14, 2023 Here's what I have. See front distribution box (trace red line from Evans Tempcon connector). Generic Evens tempcon schematics for reference Link to comment Share on other sites More sharing options...
Mike in Va Posted April 17, 2023 Author Share Posted April 17, 2023 Thanks for the pictures. I checked the 20 p fuse and it was good. I'm going to buy me a wire tracer and see if that will help. Like I said my air conditioner isn't working. The pump is seized up and was.like that when I bought the mh. Could that stop the heater and vents from working? Link to comment Share on other sites More sharing options...
Tom Cherry Posted April 17, 2023 Share Posted April 17, 2023 Yes. But with a caveat. I included my 2009 Camelot Front HVAC print. I KNOW that your MH is different, but, fundamentally, your Vacuum pump is PROBABLY operated by the HVAC switch....I looked at the prints that were also provided and they do not show...but that is not necessarily "how Monaco installed" the system. If I leave off the AC (Switch OFF), and start the MH in storage, there is NO "noise" from my Vacuum generator. BUT, if I leave it in any mode, then the Vacuum generator comes on for maybe less than a minute and restores the vacuum needed to operate the controls. Mine, if you look, gets power from the HVAC Switch. Which is LOGICAL if you think about it. Since you do NOT have power, if I understand correctly, to the HVAC system, then you need to focus on that. As far as your AC goes, I assume you have pulled the power line from the AC clutch in the Engine compartment. That will leave the clutch disengaged and the compressor will not run or try to run. Bob's drawings are not to legible when you blow them up. I don't know if this will be better or not. I included a copy of the 2000 Knight-Ambassador drawings, which are NOT the same ones as in the files. I was able to go in via Acrobat and rotate the files so they are now "Right Side UP" his is a 2000 so odds are, both will have the details. I HOPE you have your manual and can pull or look at you prints. First step is to find the power to the HVAC system as well as the Vacuum generator, but odds are...the feed to the HVAC system will be the one powering the generator. Good Luck... @Frank McElroy I figured out HOW to rotate all the pages in the original file and now these are oriented correctly. Please check and then replace in our files. Thanks, Chassis Heating & AC.pdf 2000 Knight-Ambassador Wiring Diagrams REV 2.0 4-17-23.pdf Link to comment Share on other sites More sharing options...
Frank McElroy Posted April 17, 2023 Share Posted April 17, 2023 1 hour ago, Tom Cherry said: Yes. But with a caveat. I included my 2009 Camelot Front HVAC print. I KNOW that your MH is different, but, fundamentally, your Vacuum pump is PROBABLY operated by the HVAC switch....I looked at the prints that were also provided and they do not show...but that is not necessarily "how Monaco installed" the system. If I leave off the AC (Switch OFF), and start the MH in storage, there is NO "noise" from my Vacuum generator. BUT, if I leave it in any mode, then the Vacuum generator comes on for maybe less than a minute and restores the vacuum needed to operate the controls. Mine, if you look, gets power from the HVAC Switch. Which is LOGICAL if you think about it. Since you do NOT have power, if I understand correctly, to the HVAC system, then you need to focus on that. As far as your AC goes, I assume you have pulled the power line from the AC clutch in the Engine compartment. That will leave the clutch disengaged and the compressor will not run or try to run. Bob's drawings are not to legible when you blow them up. I don't know if this will be better or not. I included a copy of the 2000 Knight-Ambassador drawings, which are NOT the same ones as in the files. I was able to go in via Acrobat and rotate the files so they are now "Right Side UP" his is a 2000 so odds are, both will have the details. I HOPE you have your manual and can pull or look at you prints. First step is to find the power to the HVAC system as well as the Vacuum generator, but odds are...the feed to the HVAC system will be the one powering the generator. Good Luck... @Frank McElroy I figured out HOW to rotate all the pages in the original file and now these are oriented correctly. Please check and then replace in our files. Thanks, Chassis Heating & AC.pdf 106.85 kB · 1 download 2000 Knight-Ambassador Wiring Diagrams REV 2.0 4-17-23.pdf 1.99 MB · 2 downloads File has been updated. Thanks Tom. Link to comment Share on other sites More sharing options...
Mike in Va Posted April 17, 2023 Author Share Posted April 17, 2023 Tom I did unplug the compressor because I was afraid it might blow a fuse if it tries to come on because it's locked up. The 20 amp fuse label hvac in the front left side compartment is good. There is no current going to the control knob on the dash panel. I took the vacuum generator off and cleaned it good. Noticed had plenty of air coming from my air tank to the generator. I think it's a matter of finding why I'm not gettting power to the control switch. Still looking for a fuse or switch I can't find. Thanks Link to comment Share on other sites More sharing options...
Tom Cherry Posted April 17, 2023 Share Posted April 17, 2023 1 hour ago, Mike in Va said: Tom I did unplug the compressor because I was afraid it might blow a fuse if it tries to come on because it's locked up. The 20 amp fuse label hvac in the front left side compartment is good. There is no current going to the control knob on the dash panel. I took the vacuum generator off and cleaned it good. Noticed had plenty of air coming from my air tank to the generator. I think it's a matter of finding why I'm not gettting power to the control switch. Still looking for a fuse or switch I can't find. Thanks I didn’t blow up any of the prints as I had a doctor’s appointment. If the 20 amp fuse is good, and the prints show it’s SUPPOSED to go to the HVAC then I would use an old trick. Check which side of the fuse is the “fused” or power OUT. Remove the fuse, use a similar sized terminal or a bent paper clip or something in the Power OUT (maybe an alligator clip and then use a long piece of # 18 or so hookup wire and run it inside to where then run it inside. Attach (alligator clip) to one meter probe and then start probing the harness going into the HVAC system. ONE of those has to be the power line, assuming that 20 amp fuse is the HVAC one. If you can find a schematic, then cross reference. You may well have a problem in the connection or a pigtail. Keep chasing it… Link to comment Share on other sites More sharing options...
Mike in Va Posted April 17, 2023 Author Share Posted April 17, 2023 Thanks Tom. I'm away from home for a few days but soon as I get back I'm give this a try. Link to comment Share on other sites More sharing options...
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