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Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 14436
Experience:  Certified on Onan and Generac generators
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The generator runs but does not produce electricity to the

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The generator runs but does not produce electricity to the RV. Does not give a fault code.
Can you help?
Thank you for choosing Just Answer for the solution to your problem.
My name is XXXXX XXXXX I am going to assist you with this.

This set will not run if is it not making any electricity, so for now we will assume everything is good at the genset.

The most likely issue is that your transfer switch (TS) is bad.

You will need to find your transfer switch and test it.
The TS is most often located in the same compartment as where you store your shore cord.
Both the genset leads and shore cord will connect directly to the TS.
Remove the cover from the TS, and use the schematic on the inside of the cover to determine which leads come from the genset, which leads come from the shore cord, and which leads go to the coach.
Start the genset, let it run for 1 minute (to allow the TS to activate), and test both the red and black leads coming from the genset. Both should show 120V to neutral.
If they do not, let me know.

If the genset power is good, test both the red and black leads that go out to the coach. Both should show 120V to neutral.
If you have power going in to the TS, but no power coming out, the TS is bad.

If you have power coming out of the TS, the problem is in the main breaker box of the coach.

Let me know what you find.
Customer: replied 4 years ago.

I have done what you said, but I do not have power in the red and black leads coming from the genset. What do I do now?

First, make sure both breakers are on at the genset.

If they are, there is a small access panel opposite the start switch, right on the corner of the genset.
Remove this panel to access the output terminals.
Start the genset, and measure for voltage from the white wire to the black wire, then from the white wire to the red wire.

What are these 2 voltages?
Customer: replied 4 years ago.

We have taken the access panel off and the only wires inside are all white. The only black ones are on the breakers and they (the breakers) test OK.

And is it safe to start the generator while the coach is plugged in to electricity?


You pulled the wrong panel.

That one is on the front of the set, and the one you need to pull is on the rear of the set.

If the set is mounted in the front end of your coach, you will actually be looking at the left end of the genset, not the front.
The switch would be to your right, and the terminal access panel to the left.

Yes, it is no problem to start the set with the coach plugged in.
Customer: replied 4 years ago.

Well this may be a problem because our coach is gas and the set is on the curb side. So the back would be hard to get to. Do you have any idea how to reach it?

I have made a mistake.
I had you confused with another customer who has a different set.
Your set does not have that access cover.
Instead, there is a conduit coming out of the left hand side of your set. This conduit is only 30" long, and will lead right to a junction box.
You will need to take the cover off that junction box.
It is most often located in the same compartment as the genset, but may be in the next compartment over.
Sorry about that.
Customer: replied 4 years ago.
Thanks we will try this approach, however, it is getting dark so we will contact you tomorrow to finish this, we hope. So I guess once we get the junction box open then we can test the red and black?
Yes - there will be 5 wires coming from the genset. A green, a black, a red, and (2) white.
Customer: replied 4 years ago.
OK we will contact you in the a. m. to what we find inside. thanks
No problem.
Customer: replied 4 years ago.

There is a green, a black, a black with a yellow line on it, and 2 white wires. The voltage is 120.

Good morning Hank.....

If you are getting 120V at the junction box, the genset is producing power.

Check the connections in the junction box to make sure they are good.
Then you will need to go back to the TS.

If you have power at the junction box, you should have power at the TS - it is a direct run from the junction box to the TS.
Customer: replied 4 years ago.

We have electricity to the TS, but it still does not produce electricity inside the coach.

Now you know you have power to the TS.
What you need to do next is to test the output of the TS.
The leads will be marked 'To coach' or 'Load', or something similar.

Remember to let the genset run for about a minute before testing, to allow the timer of the TS to activate the TS.
If you have no power leaving the TS, the TS is bad and will need to be replaced.
Customer: replied 4 years ago.

Do you know where we can get a model ITS-50R transfer switch? We do not feel confident in pulling these large leads and testing the TS. We are in Oklahoma


You do not need to pull the leads off to test - you just touch the meter leads to the terminals where the wires are attached.

If your TS is bad, you will not find an ITS-50R, as Iota has gone out of business.
You would need to replace it with another brand of TS, which will be available through any RV dealer.
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