weighman695 Posted January 5, 2022 Share Posted January 5, 2022 Hello Everyone, I am on a full hook-up in a campground here in Las Vegas. Yesterday, I tried to start my coach engine. The engine was not able to run. I checked on my chassis batteries (two Interstate 31-MHD) voltage and it showed 11.75 Volts. I tried using the battery boost feature of my coach (pressing and holding the battery boost switch for at least 2 minutes as suggested on you tube) and switching the ignition to start. No go. I then used a cable booster to jump my chassis batteries using the house batteries. The engine started easily. I ran the engine on idle for about 40 minutes and checked the chassis batteries. Reading showed 12.57 Volts. This morning, I checked my chassis batteries voltage and it showed 12.20 Volts. I then ran again the engine using my chassis batteries (no cable booster cable attached to jump using house batteries. The engine started easily. I then ran the engine on idle for 20 minutes and measured the battery voltage. Meter showed 12.40V. I then disconnected my chassis batteries using the battery disconnect. I will measure the voltage again tomorrow to the voltage will drop substantially. My motorhome is a 2007 Monaco Camelot 40PDQ. Did somebody here in the forum experienced the above and what did you do to solve the issue? Thanks to everybody and Happy New Year!!!! Link to comment Share on other sites More sharing options...
BradHend Posted January 6, 2022 Share Posted January 6, 2022 Is that solenoid underneath the two red battery disconnects clicking when you press the boost button? Link to comment Share on other sites More sharing options...
weighman695 Posted January 6, 2022 Author Share Posted January 6, 2022 I have not tried that yet. My battery boost switch is in my dashboard, so I have to as DW to listen. Currently, the engine can start using the chassis batteries since it was charged by the alternator. Can I still use the battery boost even though the batteries are charged? Link to comment Share on other sites More sharing options...
waterskier_1 Posted January 6, 2022 Share Posted January 6, 2022 Check the voltage on each side of that solenoid - it should be the same. I suspect that solenoid - either not energizing, but even if it is, the contacts inside are likely faulty. I also question your chassis battery - it should be close to 14.2 when the engine is running. It should be 12.7 Volts when charged. 12.1 - 12.2 Volts is the minimum you should let it get (really, never that low for a starting battery). Link to comment Share on other sites More sharing options...
BradHend Posted January 6, 2022 Share Posted January 6, 2022 That solenoid is what connects your house batteries in parallel with your coach batteries when you press the boost switch up front. If it isn’t clicking, check for power (12VDC) at the solenoid terminals when pressing the boost switch. You *can* use the switch, but if it’s starting the engine, what’s the need to use it? Link to comment Share on other sites More sharing options...
weighman695 Posted January 6, 2022 Author Share Posted January 6, 2022 My understanding is that the chassis batteries are being charged while on shore power. Is my understanding correct. I would like to know also why the battery was discharged if the batteries are being charged while the coach is on shore power so I can fix the issue. If the problem is the solenoid, then I have to replace the solenoid. If the problem is something else, then I have to take action to resolve the issue. Right now, I have no idea what the problem is. Thank you for your help. I have just asked my DW to press and hold the battery boost while I am listening to the sound of the solenoid. I heard one click when my wife pressed and held the switch by approximately 5 seconds. I also noticed that the solenoid was warm to the touch when the batteries are connected to the coach. But when I disconnected the batteries using the battery disconnect, the solenoid feels cold. What does that one click indicates? Thanks... Link to comment Share on other sites More sharing options...
weighman695 Posted January 6, 2022 Author Share Posted January 6, 2022 38 minutes ago, waterskier_1 said: Check the voltage on each side of that solenoid - it should be the same. I suspect that solenoid - either not energizing, but even if it is, the contacts inside are likely faulty. I also question your chassis battery - it should be close to 14.2 when the engine is running. It should be 12.7 Volts when charged. 12.1 - 12.2 Volts is the minimum you should let it get (really, never that low for a starting battery). To clarify, the battery voltage was measured 11.75 Volts and can't start the engine. The chassis batteries was jump started using the house batteries. After 40 minutes of idling and after turning off the engine, the batteries are measured to be 12.57 Volts. The batteries were disconnected using battery disconnect switch. Next morning, the batteries are measured to be 12.20 Volts (again, measured when the engine was off). Newbie question, how do you "Check the voltage on each side of that solenoid - it should be the same". Where to I put the negative and positive probe when measuring? Link to comment Share on other sites More sharing options...
BradHend Posted January 6, 2022 Share Posted January 6, 2022 Positive lead on purple, negative lead on white. When the switch is activated you should be seeing 12V. If you hook it up backwards, it’s fine, your meter would just show -12V As to why you experienced that in the first place…could be a pleather of things not even related to the battery. I’d wait and see if it does it again, the problem will no doubt rear it’s head if there is something strange going on. Link to comment Share on other sites More sharing options...
1nolaguy Posted January 6, 2022 Share Posted January 6, 2022 Weighman695, do not assume your chassis batteries are charged when connected to shore power. This can vary from coach to coach, model year to model year. I initially made the same assumption until I learned otherwise. Our 2005 Monaco Safari Cheetah DST does not automatically charge the chassis batteries when on shore power. That was an add on "Smart Charger" that could be bought for several hundred dollars. As an alternative I purchased a 4 amp digital charger from Harbor Freight and plugged it into my Aims I/C that must be on whether I am connected to shore, genny in order to operate 110v in the coach. That keeps both the huse and chassis batteries topped off. Link to comment Share on other sites More sharing options...
weighman695 Posted January 6, 2022 Author Share Posted January 6, 2022 47 minutes ago, BradHend said: Positive lead on purple, negative lead on white. When the switch is activated you should be seeing 12V. If you hook it up backwards, it’s fine, your meter would just show -12V As to why you experienced that in the first place…could be a pleather of things not even related to the battery. I’d wait and see if it does it again, the problem will no doubt rear it’s head if there is something strange going on. Thank you Brad. I will try that tomorrow. I am learning a lot from this forum. Another newbie question. How do I know if the shore power is charging (or not) my chassis batteries? What do I have to look out? Use of multimeter for example? How? Thanks... Link to comment Share on other sites More sharing options...
Frank Bergamo Posted January 6, 2022 Share Posted January 6, 2022 If your chassis batteries are above 13 volts, it is charging. Put your red lead of the volt meter on the positive, the black on the negative. Make sure your volt meter is set to DC current. Hope this helps. Link to comment Share on other sites More sharing options...
weighman695 Posted January 6, 2022 Author Share Posted January 6, 2022 2 hours ago, BradHend said: That solenoid is what connects your house batteries in parallel with your coach batteries when you press the boost switch up front. If it isn’t clicking, check for power (12VDC) at the solenoid terminals when pressing the boost switch. You *can* use the switch, but if it’s starting the engine, what’s the need to use it? I have just asked my DW to press and hold the battery boost while I am listening to the sound of the solenoid. I heard one click when my wife pressed and held the switch by approximately 5 seconds. I also noticed that the solenoid was warm to the touch when the batteries are connected to the coach. But when I disconnected the batteries using the battery disconnect, the solenoid feels cold. What does that one click indicates? Link to comment Share on other sites More sharing options...
BradHend Posted January 6, 2022 Share Posted January 6, 2022 (edited) That click is the solenoid plunger moving and basically activating a bigger switch that connects your house and chassis battery. It sounds like you now know the solenoid is changing state when your DW hits the switch up front, so that seems to check out okay. You said that hitting that switch had no effect on trying to start your coach up and that the solenoid was getting quite warm when it was energized. I’m not sure what the fail rate is on the internal contacts, but it might not hurt to take a resistance reading across the terminals, with the wires safely removed of course. 😀. Take a couple readings and let us know your numbers. Edited January 6, 2022 by BradHend Link to comment Share on other sites More sharing options...
weighman695 Posted January 6, 2022 Author Share Posted January 6, 2022 17 minutes ago, BradHend said: That click is the solenoid plunger moving and basically activating a bigger switch that connects your house and chassis battery. It sounds like you now know the solenoid is changing state when your DW hits the switch up front, so that seems to check out okay. You said that hitting that switch had no effect on trying to start your coach up and that the solenoid was getting quite warm when it was energized. I’m not sure what the fail rate is on the internal contacts, but it might not hurt to take a resistance reading across the terminals, with the wires safely removed of course. 😀. Take a couple readings and let us know your numbers. Here the newbie go again. When you said "with the wires safely removed, do you mean all the wires connected to the solenoid or just the purple and white wires only together with the diode? Should I switch the battery disconnect to OFF position before removing all the wires? I assume that I will put the positive lead to where the purple wire used to be and the negative lead where the white wire used to be; is that a correct assumption? Also, in taking the resistance measurement, which Ohms setting the multimeter dial should be; 2000K, 200k, 20k, 2000 or 200? As I said, I am new to this so please bear with me. Thanks.... 52 minutes ago, Frank Bergamo said: If your chassis batteries are above 13 volts, it is charging. Put your red lead of the volt meter on the positive, the black on the negative. Make sure your volt meter is set to DC current. Hope this helps. Frank, As I mentioned above, the battery voltage was measured 11.75 Volts and can't start the engine. The chassis batteries was jump started using the house batteries. After 40 minutes of idling and after turning off the engine, the batteries are measured to be 12.57 Volts. The batteries were disconnected using battery disconnect switch. Next morning, the batteries are measured to be 12.20 Volts (again, measured when the engine was off). I did not get above 13 Volts measurement with the engine OFF. Does that mean the shore power is not charging the chassis batteries? Link to comment Share on other sites More sharing options...
Frank Bergamo Posted January 6, 2022 Share Posted January 6, 2022 The solenoid is not working properly if pushing boost switch and no start. When jumping batteries with cables and coach starts you are just bypassing solenoid to start coach. As far as chassis batteries are concerned, they obviously are not charging on shore power. You will need to figure out what kind of system you have that ties the batteries together when on shore power, and what is not working properly. Hope this helps. Link to comment Share on other sites More sharing options...
Aridjoe Posted January 6, 2022 Share Posted January 6, 2022 My 2006 Diplomat has a substantial solenoid mounted in the battery compartment that provides the circuit between the house and chassis batteries when the battery boost switch is pushed. That is the solenoid you are bypassing when you use the jumper cables. It went out on mine and I had to replace it. I would make sure the voltage is getting to the switching lead on the solenoid when the boost switch is pushed, verify the solenoid is making noise when the voltage is applied, and then if the voltage on the chassis batteries goes up when the solenoid is activated. Good luck! Link to comment Share on other sites More sharing options...
weighman695 Posted January 6, 2022 Author Share Posted January 6, 2022 22 minutes ago, Aridjoe said: My 2006 Diplomat has a substantial solenoid mounted in the battery compartment that provides the circuit between the house and chassis batteries when the battery boost switch is pushed. That is the solenoid you are bypassing when you use the jumper cables. It went out on mine and I had to replace it. I would make sure the voltage is getting to the switching lead on the solenoid when the boost switch is pushed, verify the solenoid is making noise when the voltage is applied, and then if the voltage on the chassis batteries goes up when the solenoid is activated. Good luck! Will do. Thanks... Link to comment Share on other sites More sharing options...
Gary Cole Posted January 6, 2022 Share Posted January 6, 2022 (edited) A low resistance reading across the contacts does not necessarily mean a solenoid is OK. Still might not be able to provide low resistance path for heavy current draw which is required by the starter due to reduced contact area from normal wear. Contacts also need a minimum clamping pressure in order to conduct heavy current. A better way is to engage the solenoid and check for voltage potential across the posts while the solenoid is conducting a heavy current. Should zero or very close. Might have a bad cell in one of your start batteries. Disconnect them and check each one individually for resting voltage. Edited January 6, 2022 by Gary Cole Link to comment Share on other sites More sharing options...
waterskier_1 Posted January 6, 2022 Share Posted January 6, 2022 5 hours ago, weighman695 said: To clarify, the battery voltage was measured 11.75 Volts and can't start the engine. The chassis batteries was jump started using the house batteries. After 40 minutes of idling and after turning off the engine, the batteries are measured to be 12.57 Volts. The batteries were disconnected using battery disconnect switch. Next morning, the batteries are measured to be 12.20 Volts (again, measured when the engine was off). Newbie question, how do you "Check the voltage on each side of that solenoid - it should be the same". Where to I put the negative and positive probe when measuring? You put the positive lead on one of the large connectors of the solenoid, and the other lead of the meter on ground. Then move the positive lead to the other large connector leaving the ground lead attached. If the solenoid is working, then the voltage on each side would be the same. Just because you hear the solenoid clicks & gets warm only tells you the coil is energized. It doesn't tell you that the contacts inside the solenoid are making good contact. Indeed, the main failure of that solenoid are the contacts getting dirty. I think there is a white paper in the files section describing house to disassemble & clean the contacts. But that is moot if you are replacing it. Link to comment Share on other sites More sharing options...
jimc99999 Posted January 6, 2022 Share Posted January 6, 2022 On my 97 Windsor the battery boost solenoid never worked properly (at least since 2018 when I bought the coach). It clicked, and I tested continuity, but it apparently couldn't pass enough current to accomplish anything. I never thought to test voltage differential. It's been replaced by the BlueSea ML-ACR now. Link to comment Share on other sites More sharing options...
MyronTruex Posted January 6, 2022 Share Posted January 6, 2022 (edited) Order a replacement for that solenoid and in the mean time just bolt the cables together and tape them up. Of course turn power off when doing this. Your clues are sufficient to not even have to take a voltage measurement. 1> Does not start when pushing the aux start button .. (That engages that solenoid which is a very very common problem part) 2> The Solenoid is warm or hot to the touch. This solenoid takes a lot of power while activated and will get warm or even hot to the touch.. This tells me it is being commanded to energize. But even if it goes clunk and seems to energize that does not mean the contacts are working. 3>Using jumper cables works. If you either leave one jumper cable in place to bypass the solenoid while it is on order both banks will charge but it can take hours to catch up. After charging for several hours you can then check the voltage on the starting batteries after turning on headlights for ten minutes. ----------------------------------------------------------------------------------------------------------------------------------------------------------- Edited January 6, 2022 by myrontruex Link to comment Share on other sites More sharing options...
amphi_sc Posted January 6, 2022 Share Posted January 6, 2022 The big boy solenoid internal contacts need polishing. Solenoid feel warm means it's engaging but contacts to corroded to conduct. Fairly easy to fix. I replaced mine, and then took apart the old one cleaning the copper contract points and carry that old as a spare. Yes, symptoms: Chassis not charging on shore power & house not charging from alternator & battery boost not helping start engine as chassis parasitic loads drag them down. When it clicks to engage the voltages are not the same on both sides of the big lugs....and it should be the same... Link to comment Share on other sites More sharing options...
weighman695 Posted January 7, 2022 Author Share Posted January 7, 2022 8 hours ago, amphi_sc said: The big boy solenoid internal contacts need polishing. Solenoid feel warm means it's engaging but contacts to corroded to conduct. Fairly easy to fix. I replaced mine, and then took apart the old one cleaning the copper contract points and carry that old as a spare. Yes, symptoms: Chassis not charging on shore power & house not charging from alternator & battery boost not helping start engine as chassis parasitic loads drag them down. When it clicks to engage the voltages are not the same on both sides of the big lugs....and it should be the same... Thanks Amphi_sc, Exactly what I am getting!!! (Chassis not charging on shore power & house not charging from alternator & battery boost not helping start engine as chassis parasitic loads drag them down. When it clicks to engage the voltages are not the same on both sides of the big lugs). I just measured this morning the voltages at the big lugs when the solenoid is engaged and I am getting 13.74 Volts on house terminal and 12.33 Volts on Chassis terminal. New Trombetta solenoid is coming in tomorrow and will replace the existing on Saturday. Hopefully it will fix the problem. BTW, how did you take apart and cleaned the old solenoid? Mine is Trombetta 114-1211-010 (copper contacts) being replaced with Trombetta 114-1211-020 (silver alloy contacts). Link to comment Share on other sites More sharing options...
amphi_sc Posted January 7, 2022 Share Posted January 7, 2022 5 minutes ago, weighman695 said: Thanks Amphi_sc, ...BTW, how did you take apart and cleaned the old solenoid? Mine is Trombetta 114-1211-010 (copper contacts) being replaced with Trombetta 114-1211-020 (silver alloy contacts). Mine was a big boy. Just removed the two bolts holding it together and carefully separated it paying close attention to the fine wires connecting the contact poles. Then just scrubbed it (poles and circular disk) with a wire grinder and fine sandpaper. After my copper looked pretty I reassembled and tested. Link to comment Share on other sites More sharing options...
weighman695 Posted January 8, 2022 Author Share Posted January 8, 2022 Update: I brought the two interstate chassis batteries (31-MHD) to Interstate Batteries of Las Vegas. The batteries are discharged. Prior to bringing the batteries to Interstate, I tested the batteries using TOPDON ArtiBattery 101 12V battery tester. Results showed REPLACE. So, I bought two (2) new Interstate batteries 31-MHD date codes 12/21. Also, the Trombetta 114-1211-020 (Silver Alloy Contacts) arrived today. I install the two new batteries and replace the existing trombetta solenoid with new the new Trombetta 114-1211-020 (Silver Alloy Contacts). Here are the following measurements: Prior to installation and measured at battery terminals: both 12.72 Volts After installation with solenoid activated (by pressing and holding battery boost switch on the dashboard): Measured at top left lug of the trombetta (solenoid) : 13.51 Volts Measured at top right lug of the trombetta (solenoid) : 13.51 Volts Measured at bottom lug of the solenoid (positive lead on small lug where purple wire and negative lead where white wire) : 11.50 Volts Measured chassis battery with both batteries on parallel (house and chassis battery disconnects on; solenoid NOT activated) : 12.72 Volts Measured house battery@4-6V Trojan battery series parallel (house and chassis battery disconnects on; solenoid NOT activated) : 13.60 Volts Now folks, what does this data indicates? Am I charging the chassis batteries now? If not, what else I can do or test. Let me know. Thanks.... 1 Link to comment Share on other sites More sharing options...
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