House batteries went low with cold weather(2 lithium pro batteries),removed from coach and charged and reinstalled,everything
in the hookup looks good,went to start coach after a couple of cold days and won't start.The 2 start batteries are fully charged,
you turn the key to the on position and the start relay energies for about 5 seconds the shuts off,after a few more seconds it comes back and repeats the process,this is the relay on the bottom of the panel by the stairs to the right of a similar relay,I
changed the relay,no difference,if you turn the key past the on position you get nothing.Coach was started about 2 weeks ago with no problem,thanks in advance.Coach is next to the shop and it's warm for awhile can trouble shoot.
That is one of two identical ignition relays. They are activated by a signal from the ignition switch. It is possible you have a intermittent wiring connection or loose wire in the activation circuit, or a bad ignition switch.
On the schematic linked below, at the top left of center you will see the 2 ignition relays. To the left of them is the main HOT (engine battery) power distribution post, and to the left of that is the ignition switch. Power departs the IGN terminal in the ignition switch via the wire 103 WH and goes into the wiring harness. It comes out of the harness via wire 103A WH and goes to the activation terminals (86) on the two ignition relays.
I would suggest checking the main HOT power distribution post to be sure you have good (engine battery) voltage there.
Then check the wires on the 103 WH circuit from the ignition switch to the ignition relays for any intermittent loose connections.
If that stuff checks good, then you may need a new ignition switch. Check by jumping power directly from HOT power distribution post to the activation terminal (86) on each ignition solenoid. If the solenoids activate properly, then the ignition switch is suspect.
https://www.foreforums.com/index.php?media/file/b-2179-e31-12v-wire-u320.3300/
Will do that and go from there.
With this frequency it may be caused by the auto resetting breaker that controls ignition. Check that breaker to see if it is bad and the wiring to same breaker has a bad spot. You may need to unplug the ignition switch plug and check the ignition switch for a short.
Mike
Or could be the coil is going bad and drawing to much current.
These diagrams likely are how current flows when you turn the ignition key.
You can work backward to get the engine cranking without the ignition key.
The sequence can be VERY helpful when diagnosing a failure to crank problem.
Still trying to figure out which parts are which,ordered a new ig switch from Napa,Barry read your post about replacing your switch
got the chrome piece loose but will not come all the way off,is there a detent somewhere to get off completly?
If there is a round hole in the chrome piece push a paperclip into the hole to release.
UPDATE: Installed new Ignition switch,same problem with new switch,checked the components on the metal plate that is in the back near the six pack(some are under the bed near the fuse panel),swapped out the 2 small relays,both good,of the 2 cole
hersee solenoids,the one with the smaller wires is the boost the one with the larger wires is the start solenoid(correct me if
wrong),the start solenoid has battery woltage but when I jump from battery voltage to iniciate the solenoid it makes the clicking sound and no voltage to the starter,(yes I did tap on it).Today will be checking voltage from switch to that solenoid,have a new
solenoid coming today(cole hersee 24213,still not sure how this would be causing the start relay in the front panel to cycle,any
ideas appreciated as always.
Does the engine have an air manifold heater?
I think you might have the solenoid IDs reversed.
The BOOST solenoid will have large battery cables on both of the big posts. Both of these cables should be hot all the time. When the solenoid is OFF (open), one large post will read chassis battery bank voltage, and the other will read coach battery bank voltage. When the solenoid is ON (closed) the voltage should equalize and read the same on both large posts.
The AUX START solenoid should have smaller gauge wires on the large posts. When the solenoid is OFF (open) there should be voltage on only
one of the large posts. When the solenoid is ON (closed) there should be voltage on both large posts, and the starter motor should try to crank the engine.
Yes to Craneman,will unplug and see what happens.
Checked the aux. start solenoid,no voltage to either big terminals,will try and figure that out,also on the boost solenoid voltage
only on one big terminal,will figure out if house or start batteries.
The aux start solenoid would usually receive the voltage on the large always HOT post from the chassis (start) battery bank.
Since the aux start solenoid is missing the voltage from the chassis batteries, I would
guess this is also the voltage that is missing from the boost solenoid.
On our '93 model the original factory wired path of start battery voltage went from the chassis batteries to a large post on the boost solenoid, then to the isolator start battery post, then to the aux start solenoid, then it passed through the aux start solenoid and on to the starter solenoid (mounted on the starter). The newer model coaches might be different, IDK.
See generic 12V wiring schematic linked below:
https://www.foreforums.com/index.php?media/file/b-2126-automotive-wiring-diagram.4746/
Have that drawing in my books,went over the cables on the house batteries,they check out ok,B12 AND B39 wires check out ok,have 12 volt to 12volt circuits,will check the B11,and go from there,looks like that sould be a straight path from battery to boost solenoid.
Going to go thru Barrys checklist today,will also check intake heater and fuel solenoid,may be dealing with a short somewhere.
Barry,on the end of the second page,not sure what/where the inverter panel is?
Craneman,isolated preheat,no change,cleaned all grounds on engine and frame,think I'll try and isolate every resettable fuse on the front panel area one by one and see what that does.Still can't figure out why the ignition relay acts like a resetable fuse.
Pull out the ignition relay and see if something still is tripping. If not it is downstream of the ignition relay.
John, earlier you mentioned the start batteries were fully charged. I'm curious if they really are fully charged and able to provide good starting voltage.
Try turning on the headlights with the ignition switch off. Do the headlights turn on with normal brightness?
Then turn the ignition switch to the "on" position. Do the headlights stay bright or do they get noticably much dimmer when the relay cycles?
Then try to crank the engine, do the headlights go way down to nothing or stay bright?
Will do but when you turn the key to the first position everything is ok for about 5 seconds,then the lower right bosch ignition
solenoid cycles on and off,if you go to the start position,nothing.going to trace the starting voltage in the morning.
In Reply #3 Mike suggested checking the auto resetting circuit breaker that controls ignition. Did you ever do that?
In the 12V wiring schematic for your coach, you are looking for the circuit breaker marked IGNITION SWITCH 15. This circuit breaker feeds wire 91 WH which sends power to the ignition switch terminal marked BAT. As Mike suggested, if this circuit breaker is weak it could repeatedly open and close, giving the intermittent power symptom you describe.
Schematic below (for U320) shows the circuit breaker. It may be in a different position on your circuit breaker panel.
Will do that next Chuck and give update,getting some extra breakers coming just in case,thanks again.
Coach wont start trouble shooting (Battery) (https://www.foreforums.com/index.php?topic=45820.0)
Low Capacity batteries and resistance in cables and grounds are so easy to over look. You use your volt meter and see power, but it needs to remain under load.
I'm thinking bad starter....have you tried jumping the solenoid...IMHO
Chuck,got some progress,did that procedure ,replaced with new breaker,same thing happens when you turn key the one turn
to the right but when you go start position for the few seconds before the solenoid cycles the start solenoid near the isolator
clicks,this was not happening before.will trace from there.
Hans,to your question,not yet.Took all the ground wires at the bottom of the front panel area that are on the ground lug and cleaned and put back.
John44, this is a belt and suspenders check but first things first:
Have you put a voltmeter on the start batteries and had someone watch the voltage while you try and turn the engine with the starter?
Art Joly
Sent you message,thanks.
Jumped the starter from the main cable on the starter,B1 to the starter solenoid,had the starter solenoid wire off,turned over but
kept on turning when I removed jumper,had to disconnect battery cable,did'nt start because fuel valve not open,after that with
the start solenoid wire still off when turning the key still get the solenoid cycling,have to figure out what"s going on with that.
Sounds like starter solenoid sticking, is the circuit breaker still tripping with the wire removed from the solenoid at the starter?
Yes,will try and figure out that part next,wonder if this starter is the type that disengages after a certain RPM?
Not that I know of on the starter.
The ring gear will disengage the starter pinion when the engine starts. The motor itself will spin until that happens or the battery runs dead.
Thought about this last night,the large relay cycling starts when you turn the key to the first position,the red lights on the dash
come on and I can hear what is probably the vacuum pump,after about 5 seconds the prcess repeats,this tells me something in
that wiring group is causing a problem,will work on that next.
If you have em around, I'd be inclined to take the lithium batteries out of the mix and try starting on 2 lead acid. Makes me wonder if the heater grid is triggering some low temp protection or something. Just spitballin' here but might be worth a try.
Going over start relay today trying to keep sane,ignition relay still cycling.
I believe your problem is the hold in winding of the starter solenoid is bad. There are two windings
in the starter solenoid. A pull in winding and a hold in winding and with the hold in winding gone it
will cycle.
The starter worked when hotwired,I have the small wire to the starter solenoid removed and ignition solenoid still cycling when
key turned to first position,keep thinking every little bit helps.
Update:Have been working from diagram B-2126 from reply13,(Have sure start 24023A installed for a few years)got the
ignition relay to stop cycling by removing the wire from the second post counting from the left,the aux start relay clicks when
turning key to start position but no voltage in or out from wires B25 and B26,I have the direction sheet for the isolator,will
remove all wires today and test per the sheet to eliminate this as a problem.Another thing am thinking about is maybe the solenoid on the starter is getting week per Old guys post.
Dave, if the aux starter solenoid is clicking when key is turned to start position, but starter is not spinning, then it sounds like your problem is from the aux solenoid back to starter.
When aux clicks when key is turned to start position, then you should show a 12 volt output on the terminal that B25 is connected to on aux solenoid. If it is not showing any voltage when key is held in start position, then either the aux solenoid is bad or the voltage source to the power input of aux is faulty.
If B25 is showing 12 volts, and starter is not spinning, then B25 wire which runs from aux solenoid to starter solenoid needs to be checked. So test this wire and ensure it's showing a 12 volt signal where it connects to main starter solenoid. If you have 12 volts when key start is held, and starter solenoid does not engage, then sounds like you have a bad starter solenoid.
Check the other main terminal on aux solenoid to make sure it has power at all times. It connects from solenoid to the isolator via B26RD wire. On this same isolator terminal is wire B12 RD which goes to one side of the Boost solenoid. From there it runs to the starter main power lug via wire B5000. This lug on starter is then tied to positive of battery, and this is how both solenoids are powered. Check these connections but remember they are always hot with direct connection to battery.
Good luck, I know finding these electrical demons can be frustrating.
That will be my next step,some of the wires on the diagram are not the same as mine so is a little harder.thanks for the help.
Installed new aux start solenoid,solenoid works but I have no power from the B 26 wire,my B11 wire does not have power and it does not go to the coach batteries,tried to find another diagram for my coach but could not find one,have had this wiring setup for a few years and has worked fine and did;nt change any around,will be tracing wires tomorrow.The coach battery side of the isolator has voltage but the start battery side has no voltage(terminal 2).Need to find out where my b11 wire gos on my coach.
Still tracing the B11 cable traced to toward the front of coach,does not go to start battery per diagram,will try and get a diagram from Foretravel.
Recently I had a power problem with my front windshield shade. While standing in line for the dump site my radio was having an issue so I reached in to correct it and by accident displaced one of the wires to the shade. I went crazy trying to find why the shade wouldn't work when all I really needed to do was look at my first messing around in the dash. Found my problem with a displaced wire. The more I did the harder it would have been to find the problem so sometimes it's better to just sit back and think about what cause the problem originally.
Per our phone conversation David I would definitely check with the truck mechanic in your neighborhood.
He seemed pretty knowledgeable. I don't really have any other suggestions as electrical stuff is not my forte. Sounds like a wire is off somewhere and you just need to find it. Use the electric wire tracer to figure out where that wire goes. It wouldn't surprise me if it's where your house batteries are.
Tested the Shure power 24023 isolator per their instruction sheet,you test it with ohm meter on the diode scale from different
terminals,the isolator failed according to the sheet,their wording is "a good isolator will show current flow" and a good isolator
will show no current flow,looking to verify their wording here,from what I read current flow would be continuity,if that is the case then mine failed most of the checks and with the way all the wiring is connected that may be my problem,what ya'all think?
Also easy to test with just a voltmeter and very easy with the isolator installed in the coach-- takes less than 2 minutes.
Center lug is from alternator B+ terminal, so should show around 14 VDC with engine running.
The outer lugs each go to a battery bank (chassis and house). With a functioning diode-based battery isolator, they should each show about .7 VDC less than the center lug. Yes, this assumes that the batteries are not so deeply discharged that the alternator output can not achieve full voltage.
Good diodes should only allow current to flow in one direction. On the isolator, current should only flow from the ALT post to the two BAT posts. If current flows "backwards" then the diodes have failed.
Like I said ,of the six tests you could do they all failed,when it called for continuity I had none and when it called for no flow I had
flow,did it with 2 different meters with same results.
Your prior two posts explain fairly well what you need to check for BUT amperage is not voltage. You can easily test with your digital volt meter by checking then swapping leads to see nearly open. You are checking ohms range and or diode setting. Then go to voltage with the engine running and look for the .7 voltage drop from engine side to output too battery. If you have a cheap HF load meter you can load the output side and check voltage under load. Will be more than .7 volts but should be within that between in and out during load. Under load will revile if you have hi resistance across isolator
Coach wont start trouble shooting (Battery) (https://www.foreforums.com/index.php?topic=45820.0)
https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html Best 20$ for troubleshooting
All I can check is what the instruction sheet says to check with the engine not running and those checks fail,the problem is
the engine will not start,been working well over 2 weeks to get it to start.
May have found problem,made a pictoral diagram of my isolator panel and marked wires,have a triple 000 cable on the house battery terminal of the isolator which has NO POWER,traced it to the top area of the basement,this has got to be a power supply from the house batterys,my house battery cables go thru the top of the battery compartment,positive to the big fuse and negative
to the shunt fron the magnum charger,another red cable goes to the generator starter,all 3 of these cables go thru a hole in the wall up near the air compressor,somewhere past this hole must be a junction where the cable to the isolator connects,all
ideas welcome,(the cable from the isolator is marked B11,which does not match the wiring diagram).
There should be a round circuit breaker. That you might have to use a hammer handle to push it in. They work very hard should be where the cable goes through the wall.
Found problem,make a long story short,traced my B11 wire back to the negative side of the house batterys(I boobooed and
reconnected wrong after charging).Engine now turned over but no start,traced that to sticking fuel solenoid,have a new
Larry B's on hand will install today,will test with the hot wire to the starter solenoid removed and a voltmeter attached,if voltage
cycles with key on and off my starter solenoid may be sticking,will go from there.
Adjusted new fuel solenoid to open and close freely,checked starter per above post,key working as it should,cuts power off
but starter stays on,took to shop in Memphis,will have word around Monday.
When ignition key is not in crank/start position, Aux-Start-Solenoid's cable to starter should NOT have 12 volts. If it does have 12v, it would keep starter cranking.
That's the same thing that I said but in different words,mine works as it should,the starter keeps cranking with no aux solenoid signal.
Got engine started but no charging from alternator,have the wire from the 28si to the E terminal on the isolator but no 12 volts,have some messages sent out to a couple of ya'all.
Dave:
As we discussed on the phone:
Delco "S" Sense post should be connected to the "start" battery isolator post, or even better connect directly to the start battery.
Nothing should be connected to the Delco "I" post.
You have the correct isolator to use with a Delco alternator. The isolator "E" Excite post should be connected to something that has +12V only with key on. A typical place to get this would be at the fuel cutoff valve.
This should get your Delco to start charging.
End of story engine starting and charging as it should,when the positive cable from the house batteries was put back on the negative terminal it created a no starting problem,in trying to troubleshoot I disconnected the remote start wires(don't use it
),further troubleshooting found that's where the sense wire for the alternator was connected,reconnected and everything ok.Thanks to all who helped and the many phone calls (the 3 Chucks and Peter),lesson learned,mark the wires,mark the wires.
The sterter solenoid was on it's last leg so had to get it repaired.