Remote switches not working on Genset

[Gjac]

Finally fixed my Kohlar 5CKM21 genset and works fine from start switch on genset itself. Neither the dash remote switch or the remote start switch above the stove will start the generator. Both will work to stop the generator but no start on either. Because both switches don't work I figured the problem was not the switch itself and thought I would check the connections at the genset itself for corrosion or loose wiring first. I can see where the wires from the genset start/stop switch plug into the control board then saw 4 wires coming into that plug from another harness up front. Removed plug and re plugged several times but still no start. Any other ideas?

[Gjac]

Gjac wrote:

wborst wrote:
On the remote switches, the common connection is ground. The other two connections are to the start and stop inputs on p2. When the start wire is connected to ground, the controller begins the start sequence. When the stop wire is connected to ground, the controller begins the shutdown sequence.

On p2 on the controller, pin 1 is the start connection, pin 2 is the stop connection, and pin 3 is the ground connection. Without operating the switch, pins 1 and 2 of p2 should both measure 12 volts. With respect to pin 3. When the switch is in the either the start or stop position, the respective pin on p2 ( either 1 or 2) is connected to pin 3 of p2.

The local switch connects to pins 10, 11 and 12 of p2.

Hope this helps.

I finally found a wiring diagram and see P1 and P2. I see where P2 is the plug that the wires from the start stop switches are connected to the control board. My wiring diagram does not show The other pins that are inside the P2 plug that you referenced such as P1,2,3,10,11,and 12. Any information as to how to identify these pins would be helpful. P2 has 9 pin spaces but only 7 are used. Looks like 3 for the local start/stop switch and 4 for the remote switches.

Finally figured out the confusion Bill was referring to a Onan wiring diagram I have a Kohlar genset.

[Gjac]

wborst wrote:
On the remote switches, the common connection is ground. The other two connections are to the start and stop inputs on p2. When the start wire is connected to ground, the controller begins the start sequence. When the stop wire is connected to ground, the controller begins the shutdown sequence.

On p2 on the controller, pin 1 is the start connection, pin 2 is the stop connection, and pin 3 is the ground connection. Without operating the switch, pins 1 and 2 of p2 should both measure 12 volts. With respect to pin 3. When the switch is in the either the start or stop position, the respective pin on p2 ( either 1 or 2) is connected to pin 3 of p2.

The local switch connects to pins 10, 11 and 12 of p2.

Hope this helps.

I finally found a wiring diagram and see P1 and P2. I see where P2 is the plug that the wires from the start stop switches are connected to the control board. My wiring diagram does not show The other pins that are inside the P2 plug that you referenced such as P1,2,3,10,11,and 12. Any information as to how to identify these pins would be helpful. P2 has 9 pin spaces but only 7 are used. Looks like 3 for the local start/stop switch and 4 for the remote switches.

[garry1p]

If you jumper the yellow to ground you should have gotten a good spark from your description you shorted +12V (yellow) directly to ground.

I would think you can use wborst information above and using a short jumper wire troubleshoot at the controller bypassing all switch wiring.

[Gjac]

Thanks Bill for the explanation. I do have 3 wires going to the remote switch and read 12 v between the yellow wire and black wire and read 12v between yellow wire and metal stove hood(grd). I jumpered yellow to black wire and yellow to brown but still did not get it to crank over. I also tried to jumper yellow 12v wire to metal hood but still did not get a start. I am beginning to wonder if the board circuits are bad where remote wires connect.

[wborst]

On the remote switches, the common connection is ground. The other two connections are to the start and stop inputs on p2. When the start wire is connected to ground, the controller begins the start sequence. When the stop wire is connected to ground, the controller begins the shutdown sequence.

On p2 on the controller, pin 1 is the start connection, pin 2 is the stop connection, and pin 3 is the ground connection. Without operating the switch, pins 1 and 2 of p2 should both measure 12 volts. With respect to pin 3. When the switch is in the either the start or stop position, the respective pin on p2 ( either 1 or 2) is connected to pin 3 of p2.

The local switch connects to pins 10, 11 and 12 of p2.

Hope this helps.

[Gjac]

rgatijnet1 wrote:
About the only thing left is the path of 12 volts from the switch to the generator starter. Since the switch on the starter works, then about the only thing left is an open somewhere in the wire from the other switches to the starter. I still think that the two switches are in parallel so there may only be one wire going from them to the generator starter. I see no reason why it would not hook up to the same place as your generator starter switch rather than going to an electronic board. In other words, I am thinking all three switches should be wired in parallel.

The genset starter switch hooks up directly to the control board along with the remote starter wires. They are all in the same plug that plugs into board.

[Gjac]

MySuncoastRV wrote:
The stop portion of the switches uses a grounding circuit. The start switch uses a 12v input. The onboard switch is independent from the remote switches and that's why it functions as normal. Look for a 10amp fuse on the remote switch circuit within the generator cover. More than likely tucked within the wiring loom near the front panel. Hope this helps. Keep us posted.

Cannot see a 10 amp fuse inside genset cover. Saw and checked 2 5 amp fuses and a 15 amp fuse on the face plate and all were good. reset two 30 amp circuit breakers.

[rgatijnet1]

About the only thing left is the path of 12 volts from the switch to the generator starter. Since the switch on the starter works, then about the only thing left is an open somewhere in the wire from the other switches to the starter. I still think that the two switches are in parallel so there may only be one wire going from them to the generator starter. I see no reason why it would not hook up to the same place as your generator starter switch rather than going to an electronic board. In other words, I am thinking all three switches should be wired in parallel.

[Gjac]

rgatijnet1 wrote:
One of the problems with tracing continuity and voltage is that if even if one strand of a 100 strand wire is still connected, the voltage will read correct and so with the continuity. In spite of these good readings the single strand of wire will not have the current carrying capacity(amperage) to energize the starter. I am guessing that somewhere between the 12 volt source and the switches, the wire is frayed(maybe partially rodent eaten) to the point where it cannot supply enough amps to energize the starter.
You may want to try bringing another 12 volt source wire to the switch and see if that works.
I think that by trying the jumper cable ground connection earlier, we eliminated a frayed ground wire.

. I tied jumpering the 12v wire from my water pump to the 12v wire on my switch over the stove but still no start. This is very baffling.

[rgatijnet1]

One of the problems with tracing continuity and voltage is that if even if one strand of a 100 strand wire is still connected, the voltage will read correct and so with the continuity. In spite of these good readings the single strand of wire will not have the current carrying capacity(amperage) to energize the starter. I am guessing that somewhere between the 12 volt source and the switches, the wire is frayed(maybe partially rodent eaten) to the point where it cannot supply enough amps to energize the starter.
You may want to try bringing another 12 volt source wire to the switch and see if that works.
I think that by trying the jumper cable ground connection earlier, we eliminated a frayed ground wire.

[Gjac]

rgatijnet1 wrote:
All of the switches should be wired in parallel. Since you have voltage to the switch at the generator, then the issue should be the 12 volt feed to the other two switches. Using a voltmeter you should measure power on one side of each switch. If you do not, then you need to trace back to where the power stops. There might be a fuse in the hot line that has blown. I would expect the power to both switches to be coming from the same 12 volt source.

Yes I checked and had 12 volts at the switch over the stove. There were 3 wires to the switch yellow(12v), black and brown(grd). Black wire also goes to hr meter which works. I removed the 12v wire and shorted it out to the brown wire but still no start. Shorted yellow wire to metal hood grd still no start. I then ran a wire from the 12v yellow wire all the way back to the genset grd inside electronic box and it still would not start. I know I must be missing something I just don't know what. Checked switch and had continuity, also checked chassis grd to genset grd inside box and had continuity there also.

[rgatijnet1]

All of the switches should be wired in parallel. Since you have voltage to the switch at the generator, then the issue should be the 12 volt feed to the other two switches. Using a voltmeter you should measure power on one side of each switch. If you do not, then you need to trace back to where the power stops. There might be a fuse in the hot line that has blown. I would expect the power to both switches to be coming from the same 12 volt source.

[Gjac]

F4Jock wrote:
Had the same problem. Wires at the remote start plug on the genny were corroded. Rewired. Fixed it.

That was the first thing I checked. There was a connection from the board to the inside of the genset electronic box, then another on the outside of box, then I saw a series of wire splices going to the out side plug. From there I assumed the wires went to the remote switches. Thinking one of those 4 connections was bad I checked continuity from each splice to the control board plug and all was good.

[Gjac]

rgatijnet1 wrote:
Since both switches do not work, perhaps the problem is with the generator ground connection. Of course this is assuming that both of the generator switches have power going to them.
An easy way to check the generator ground connection is with a jumper cable clamped on from the coach frame to the generator frame.

This was a good thought, I used my battery jumper cables to try this but still no start.