BAC Forum
General Boards => Technical Support => Topic started by: Randy Stephenson on November 07, 2018, 01:35:50 AM
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I have read many posts regarding no-starting conditions, unfortunately, I have not seen suggestions for my current issue. Following is a description of events:
1. I pre-heated the C-12, retracted all slides, unplugged the coach and was ready to leave Breckenridge, CO.
2. Turned on the ignition, low air pressure sounded as normal, there was very little cracking power, seemed like low battery condition. Which was a mystery since the coach was pulled in for weeks and the inverter indicated 100% battery charge.
3. I switched the chassis and house battery switch on and off, power then showed on the dash volt meter when the key was turned. However, once I turned the key to start, low cranking was still and issue and the voltage meter on the dash gauge showed no or only 10-volts once again.
4. After several attempts of turning the chassis and house batteries on and off again, I was able to turn the engine over.
5. On the drive back to Michigan, I started and stopped the coach four times at fuel stops, the engine started up just fine.
6. After arriving home the next day I tried to start the coach, again the low cranking issue / low dash voltage condition returned. This time, I used the boost switch and the coach started. Therefore, seemed a new solenoid was needed.
7. The following day when the key was turned to start position I heard clicking sounds from the front bay. Therefore, assured me that a new solenoid was in need.
8. Today, I picked up a new solenoid and installed it (took a picture prior to removing to make sure wires were connected correctly). Once completed, there is now no-power to the dash or low pressure alarm when the key is turned to start position.
9. So, I put the old solenoid back in, same issue no power. I did turn off both the chassis and house battery switch prior to removing, installing, and re-installing the solenoids. So, I don't think I blew a fuse.
10. Volt meter check indicates there is 14.6 on the main power cable running to the solenoid, so battery charge level not does appear to be the issue.
11. When turning the key to the left for accessory mode the radio and Aladdin power up. However when turning the key to the right, there is a noticeable dim to the overhead lights, and it seems that there is a relay underway the dash coming on. The accessory mode will not work until after a few minutes go by. Hence the reason I suspect there is a circuit breaker style fuse under the dash that is tripping.
12. With the ignition switch on accessory mode, the Aladdin does not show any engine data (which it normally shows engine and trans temperature).
I'm stumped as to why there was intermediate power the dash prior to installing a new solenoid. And now, no-power on the ignition mode after installing a new solenoid and then again after re-installing the old solenoid. I am now wondering if the ignition switch could be the issue? If so, I believe I have read in the posts that it is a GM ignition switch available at auto parts stores.
Your thoughts and expertise would be very helpful, I need to get the coach winterized and into the barn for the winter.
Randy
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Randy,
Have you checked battery voltages at the batteries with a volt meter when you have a start issue? The symtoms you are describing, including a clicking igntion solenoid, all point to low battery voltage.
Steve
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Check your battery cables and connections too. A dirty cable terminal end/connection can show as normal voltage with a meter until power is demanded (like cranking engine) then it will show a large drop in voltage.
One easy test is a "voltage drop test". You put positive voltmeter probe on center of battery terminal and negative probe to furthest point you can reach (on the positive wire) (like battery disconnect switch terminal (test both sides/terminals of switch), to starter positive terminal, bat neg terminal to ground cable connection point, etc.). Then you run power through the circuit (such as cranking engine or turning on lights depending on what circuit your testing) and measure the voltage drop. A good circuit will read around .1 or .2 Volts drop (over 0.4 VDC is a problem). You can do this test from the battery center post to the battery terminal end on the same battery to measure voltage drop between post and terminal (any voltage drop means terminal is not making good connection).
It's a little hard for me to explain this test clearly, so look at this link https://www.aa1car.com/library/voltage_drop_testing.htm or https://us.autologic.com/news/how-to-perform-a-voltage-drop-test
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Steve and Mike:
Thank you for the feedback, I checked the chassis battery this morning with a multimeter. There are 13.8 volts on the chassis battery, Aladdin is showing 13.1 volts. There is 13.8 volts showing at the positive cable solenoid post too. Still have accessory power at the radio and Aladdin, but, no power to the dash gauges when the key is turned to the start position.
It is very puzzling that the key ignition start function had power prior to turning off the chassis and coach battery switch, before replacing the solenoid. Seems that there is a relay or circuit that is not coming back on when the power switches are turned back to the on position?
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Did you check power to the solenoid in the front run box? The one that powers up all the circuit breakers.
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Did you get the diode, across the bottom of the solenoid, in the right direction when you replaced it?
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Randy,
I need a reset on this.
When you turn the key to the ON position, you have no dash lights or activity??
Does the engine start notrmally when you move the key to START??
Do the dash guages etc. come back to "life" once the engine starts??
If the engine is not starting, the start 12v signal comes from CB01 in the front electrical bay to the ignition switch, then thru the tranmission Nuetral safety switch in the VIM, then to the engine start solenoid and then to the starter.
Steve
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Mike:
I have power to the solenoid, and no dash, low pressure alarm , or start function. So, is why I don't understand what caused this issue.
Roy:
I took a picture of the wire routing before replacing the solenoid. So I'm pretty sure i hooked the wires up correctly. I was thinking about reversing the two small white wires to see if there is a difference. However, was afraid of causing another issue.
Randy
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Steve:
I do not have power to the dash when the key is turned to the ignition phase. I did have power at this phase before installing the new solenoid. Then I re-installed the old solenoid, still no dash power. However, there is power to the radio on the accessory phase of the ignition switch? So , I know the switch is getting power.
I have noticed that the overhead lights dim when I turn the key to right "the ignition start phase" , no power. Then the accessory phase does not have power until after a few minutes. I suspect there is a delay fuse under the dash that resets. after waiting a bit, have power at accessory mode again, but, no dash power.
When this all started, there was dash power but very low cranking and voltage would drop to 10 volts (so I suspected the chassis battery needed charging). However, after switching the battery disconnect several times, I had full 14 volts at the dash and it started. Drove from Colorado to Michigan, stopping and starting four times without issues.
When I tried to move the coach the next day at home, is when I heard the solenoid clicking. So based on info on the site, I installed the new solenoid, thats when the no dash power started? So, I put the old solenoid back in thinking the new one was defective, again no dash power?
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Hi Randy,
I'm thinking about your electrical problem too. The solenoid you replaced, is that the one in the front elec bay (like the photo above) or are you talking about the solenoid located above the batteries in the distribution box/compartment? I just want to be sure I understand what you were working on.
If it is the front run/electric bay, the wire on the left terminal of solenoid is power from Ignition switch (hot with Key On), the terminal on the right is the solenoid coil ground.
If the solenoid is working you would have power to the entire row (copper bus bar) on the right side when the key is On. The buss bar on the left is always hot.
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Thanks Mike:
It is the solenoid in the front bay. I checked power on incoming lead it has 14.8 volts, the bank on the left side has power too. I have not checked the right side with the key on, since a relay seems to come on under the dash and shuts the ignition switch down. I'll try to check the right side with the key on in the morning.
Randy
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Could that relay under the dash be for the front/dash AC? If possible, I would turn off the dash AC controls and any other switches on dash until you figure this out. Maybe you have a short in one of those components. If you turn everything off and then engine starts or dash gauges/lights come on normally, then start turning those switches back on one at a time.
Meanwhile, I'll look at those the electrical diagrams some more and see if I can find a relay in the dash area.
Also, that solenoid you replaced, you did buy a "continuous duty" solenoid, right? Not a "momentary duty" solenoid like used for a starter circuit.
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Mike:
Thanks, I plan to start investigating under the dash, will check to make sure the fan issue off. I did get the solenoid referenced on this site.
COLE HERSEE #24059-BX
DC Solenoid, 12V DC Coil, 85A, N.O., SPST, Copper Contact, Continuous Duty
Right now, I have the old one back in, since the coach had power in the dash before I took it out. Trying to narrow down the problem.
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Randy,
It's normal for the dash accessories to lose power when the key is turned to the START position. Verify that the diode on the solenoid has the band pointed to the 12V input (toward front of coach). Also, try switching CB01 and CBO3 on the left (always hot) buss bar in the front electrical bay. CB01 is the ignition switch CB and may be tripping initally and when it cools down, resetting.
Steve
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Maybe this pic will help regarding diode placement.
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Mike:
Thank you for the continued trouble shooting help. Carefully listening in the front compartment indicated a circuit breaker was kicking on and off. Hence, the clicking sound I heard a few days ago and suspected the starter solenoid.
I just removed and checked the diode, it shows as shorted. So as a test, I removed the diode from the solenoid and now have dash power. However, I'm afraid to try starting the coach until a new diode can be found. Do you all think it is OK to start the coach without the solenoid diode?
Thanks to all for the support, hopefully, this solves the no-start dilemma! I'll advise once I find and install a new one.
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Mike:
The picture, notes, and band information is very helpful.
Thanks, Randy
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Mike:
I just removed and checked the diode, it shows as shorted. So as a test, I removed the diode from the solenoid and now have dash power. However, I'm afraid to try starting the coach until a new diode can be found. Do you all think it is OK to start the coach without the solenoid diode?
The diode is there to prevent a voltage build up (and then a potential spark across the ignition switch contacts and to prevent that voltage build up (spike) from harming any sensitive electronic components on that same circuit) when the power to the coil is cut off. When the voltage to the solenoid's coil is cut, the magnetic force created by the the coil collapses and creates an induced voltage back through the power circuit (ignition wire in this case) that was feeding the coil. So the diode was added to prevent that voltage spike.
To answer your question - Yes, you can remove the diode and you will probably never see any negative effects. IMHO. But I would get a replacement and reinstall it as soon as possible regardless. I believe the part number is IN5400 SB560 (maybe someone else can confirm this - or check wirth BCS)
Here's a good video explaining the purpose of that diode (note that in the video diagram, author shows master switch completing the ground circuit for coil. On our coaches the master switch (ignition switch) is providing the power to coil, and ground is already present.
https://www.youtube.com/watch?v=bvDuyM2e4gw
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Mike:
Thank you for your expert advice! I found a diode (part number was on mine TCI 1N540, it's a 3 amp rectifier diode) from a distributor in Florida, the cost $.20 each. I have five coming for a $1.00 and $9.00 two day priority shipping.
I learned a lot on this situation, your info about the diode got me thinking and I did a check, results was a shorted reading on the multimeter (my first experience in this area), who would of thought a clicking breaker sound was due to a shorted diode.....assumed battery condition or the solenoid was the issue! I'll confirm it's the fix once I install the new diode.
Randy
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Steve:
Thanks for your help,
Randy
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Mike:
I found a diode (part number was on mine TCI 1N540, it's a 3 amp rectifier diode) from a distributor in Florida, the cost $.20 each. I have five coming for a $1.00 and $9.00 two day priority shipping.
Randy
Thanks for providing the correct part number. Now that you will have five Diodes in your tool box, your guaranteed to never need the other four. LOL.
And $9 to ship $1 worth of parts - well I've been there too.
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Definitely, Thanks again!
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Steve and Mike:
I installed a new starter solenoid, and solenoid diode, along with chassis batteries. The coach is now starting great. It turned out that a cell was bad in each chassis battery. Steve's earlier post about a potential battery issue was on target.
Seems that the batteries were most likely the starting issue I had experienced upon departure from Breckenridge , CO for the drive back to my Michigan home base. What threw me off was the coached started just fine at fuel stops and even after a seven hour sleep stop at Cabelas parking lot in Nebraska. So, I did not consider batteries as the issue and went directly to replacing the starter solenoid.
Fortunately, today, I was able to move the coach into the barn for the winter; unfortunately, I will not be on the road again until after the Spring snow melt.
Thanks again for your help and advisement on my starting issue.
Randy
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My coach recently had a similar starting issue. Good voltage , but sluggish and intermittent starting. I have already upgraded solenoids in electrical panel.I moved to the starter itself and found the connections loose. After tightening them it works great. Its an easy check