No power to Igniton switch

RGloverii · #1 03-16-2008

I have been slowly preparing for our next weekend outing in the coach, and just found out I have NO power to my ignition switch. Turn the switch to the 'On" position, and nothing happens. I checked for power at the switch's contacts, and no power is present.

I then tried the rear start switch, and same results. No power.

Does anyone have a diagram that shows the ignition switch circuit for an SP? I have so far been unable to trace the source for the ignition switch.

As far as I can tell, all other 12v coach systems are functioning normally. Everything works except for thing that only work when the switch is 'on', like windshield wipers, and all of the buzzers and warnings.

Any help would be appreciated.

Thanks!

iamflagman · #2 03-16-2008

Quote:

Originally Posted by RGloverii

I have been slowly preparing for our next weekend outing in the coach, and just found out I have NO power to my ignition switch. Turn the switch to the 'On" position, and nothing happens. I checked for power at the switch's contacts, and no power is present.

I then tried the rear start switch, and same results. No power.

Does anyone have a diagram that shows the ignition switch circuit for an SP? I have so far been unable to trace the source for the ignition switch.

As far as I can tell, all other 12v coach systems are functioning normally. Everything works except for thing that only work when the switch is 'on', like windshield wipers, and all of the buzzers and warnings.

Any help would be appreciated.

Thanks!

I'm not sure about your SP but on my FC there is a master Battery Switch that is located near the ignition switch, that when it is in the OFF position will create the same results that you are getting. The Master Switch is a large switch and NOT a toggle switch.

RGloverii · #3 03-16-2008

Thanks for the response.

In my coach, there is the A/T (anti theft) switch located on the dashboard, which turns off mos 12v circuits (including the ignition circuit). That switch IS in the "on" position.

There is also an 'electronic master' switch in the driver's overhead compartment, which turns off ALL 12v systems. That is also 'on'.

As far as I can tell, every 12v system in the coach is working, EXCEPT the ignition & any systems that only work when the ignition switch is 'on'.

It appears that a fuse or breaker has failed, causing no power to get to the switch. Hopefully, someone can assist with locating that fuse or breaker. So far, I cannot locate it.

Thanks!!

Bill Pape · #4 03-16-2008

Robert,

Check the A/T switch, it means Anti /Theft,
There are no markings for the On (start position) it is Burglar proof,

So on our 88 FC , the rocker switch to the left side,
So do not tell anyone else,

On our 88 , (I think we have the same dash), Under the dash there are about five big screw together wire connectors, Sometimes called Military connectors or Amphenal connectors, The wires from the ignition switch are wired thru one of these connectors, and the male /female pins lose contact because of the high current and heat.
Open the connectors and look for burnt pins usually in the center of the plug, After cleaning, lubricating and still having intermittent problems,
I hard wired around the connector and these troubled pin connections.

Bill Pape · #5 03-16-2008

Robert,

Red ZF neutral button, Just another thought..................

RGloverii · #6 03-16-2008

Bill,

Thanks for the advice. So far, I have verified the following:

The A/T switch is 'on'.

I checked for power at the female end of the amphenol cable feeding the switch. No power there either.

The transmission neutral switch shouldn't be an issue. I am not trying to 'start' the coach (although it won't start). Unless I am mistaken, the trans neutral switch would only prevent 'starting'.

When I turn the ignition swith to the 'on' position (not 'start'), nothing happens. No buzzers, no indicator lights, etc.

The switch has two inputs, and two outputs. One set is for the 'on' position. The other is for the 'start' position. Neither has any power coming to it. So, assuming both positions receive their 12v+ from common source, this source has failed.

So, I am attempting to trace the wires back to their source. So far, no luck.

Thanks everyone for their help so far. Hopefully, we'll get this issue resolved soon. At least I was at home when it happened!

jwasnewski · #7 03-16-2008

I don't know the SP either. Sounds like a relay or power to a bus bar in the ignition load center may have failed. If I were trouble shooting it I would start by jumping over the A/T switch to eliminate it as the problem. I am assuming you have 14v on the volt gauge. The electronic master will not cut the ignition. Last week my master battery cutoff in the engine bay failed but that shut everything down except the 110v. You never know how these things are wired. In my coach out front behind a panel attached with camlocks are several bus bars. It is called the lower load center. One is hot constantly, another is a filtered bus bar for electronics and yet another is hot with ignition. There are also numerous relays there. You might take a volt meter and check those bus bars also. A simple task.

gcyeaw · #8 03-16-2008

Robert,
A couple of things you can check.
Do you have an OHM meter? If so, with the power off is the input to the switch grounded. If so there is a short. Another way to test is to use a 12 volt bulb. Connect one side to 12 volts and the other side to the inputs on the switch. If the lamp lights, there is a short. (leave the switch in the off position, the output sides should have a circuit through the solenoids and other equipment to ground, so the lamp would light)

Another trick if there is not a short is to use an automotive turn signal flasher wired to two 12 volt bulbs. Connect one side of the flasher to 12 volts, and the other to the center pins of the two lamps. Then ground the case lead of one lamp to the coach which makes the flasher operate, and connect the case lead of the other lamp to the input of the switch. Then you can identify the circuit with a volt meter because it will have 12 volts going on and off. The reason for the lamp is that the lamp will limit the current so you don't burn anything up if there is a short, or if you accidentally short it while troubleshooting.

dspithaler · #9 03-17-2008

Robert
Mine wouldn't start a few years ago at home and while checking around the starter I found a 12 gauge wire that was corroded off at the solenoid for the starter. Fixed the wire & it fired right up. I spent a week looking for it.

peteaeonix · #10 03-17-2008

I once had a similar problem. A ground cable in the engine compartment had worked loose.