water heater issue

You may have winterizing valve(s) in the wrong position
Possible there is no water in tank.
What valve did you not flip? If you are talking the pressure relief valve, you need to start over. Drain water heater. Close relief valve, open hot water faucet fill system using city water connection or pump via fresh water tank.
There must be air in the top of water heater tank.
You may have destroyed the 120 colt element if water heater tank was empty.

Concur that you may have burned out your 120 volt heating element if it was turned on while you were still bypassing the water heater. As far as gas goes, I've read many posts about lukewarm water being solved by closing outside taps/faucets. For future reference on water heater problems, it doesn't really matter your RV make/model. You have either a Suburban or Atwood water heater. A model number on that will really help troubleshooting.

First, even if you burnt out your electric element, your gas would still heat the water. This points either to an open valve or incorrectly positioned valve on the bypass or a dead battery. The water heater is controlled by 12 volt. If the battery is low it will not work. Now, assuming your battery is good, start here.

Check your outside shower valves and make sure they are closed. Same with the inside shower.
Next hook up a water supply and fill the water heater tank with the pressure relief valve in the open position. When water starts coming out of it, snap it closed. Now you know you have water in the tank. Next turn on the electric to the water heater. You should be able to stand outside next to it and hear noises as it heats up. I'm sure you know it will take over an hour to get the water hot.
If you are not getting any noises outside and no warmth after half an hour or so your element may be burnt out.

Next try the gas. Again if you are outside you will be able to hear it fire up and burn. It either is or it isn't.

If the burner lights, 12V is good and control board is good. If the water is noticeably warmer than the cold water along, then the tank is full and heating.

Being that only warm water is felt, it can be caused by the bypass valve being left open or the valves on the outside shower (if equipped) being open. Each of these conditions allows cold water to mix with the hot before getting to the shower.

Now that we have a few hundred more miles under our belt, I first opened the pressure relief valve and water came out. Then I went ahead and pulled the drain plug out and let it completely drain.

I then turned water on at the source and got water coming out of the drain hole, which told me that the valve that controls water going into the hot water tank was in the proper position. So, with the pressure relief valve still open and plug replaced in the drain hole, I filled the tank until water came out of the pressure relief valve. Then I closed the pressure relief valve, turned on the hot water faucet in the kitchen and let it run until there was no air in the line.

The gas side of the hot water heater has been heating now for at least 30-45 minutes and I am still waiting for it to shut off.

The water coming out of the faucet is warm to hot, but not scalding. I will probably not test the electric side until we get to our destination.

P.S. we are driving down I-5 in a heavy rain hail storm in heavy traffic. It got to the point where I had to turn on the wipers in their fastest mode. All the sudden the passenger side wiper comes off the arm and flies over the cab of the truck.

So, I pull over the to shoulder. No way can I try to exit the drivers side of the truck. So, wife crawls over the center console into the back seat. (she is recovering from knee surgery). I then scoot over get out the passenger side door and as fast as I could pull the arm up so it doesn't scratch the windshield.

Took forever to get back on the road. I call a Chev dealer and he has a replacement in stock. 33 bucks. So I head towards the dealership. Once I got off the highway I pulled over and checked if by chance the wiper made its way to the bed of the truck. Viola there it was.

Check your faucets to insure that the valves are off. Check the outside shower to verify that the faucet is shut off and the control on the head is shut off, do the same in the shower.

Make sure the bypass valve is turned all the way. It also could be broken. If you have more than one valve (e.g. one feeding the cold inlet and one along the bypass hose) make sure both are in the correct position. You could be filling the water heater and still bypassing in parallel.

Sound like it is working now to me.

Well, we have been in our spot for close to 3 weeks and I thought I would tackle why my gas side isn't working. I turned off the electric heater, turned on the gas heater and listened. I did NOT hear a sound out of the gas valve, but the ignitor did try to fire off the heater. The heater is an Atwood Model GC10A-4E I did a continuity test on the 2 amp fuse for the module, and it is good. There's also a fusible link that tests good but the contacts were a bit corroded. I had read somewhere about replacing the module with a barracuda brand module. I have not been able to google that brand of module.

The electric side of the hot water heater has seemed to have quit heating also. We had super hot water on that side. I don't see anywhere on the heater where the electric element would be located. Also, would it be worth replacing the thermostat board? They appear to be fairly inexpensive.

So, just now I went out and did a manual lighting of the gas side. So, the valve is good. What's weird is that when it is going through its 'trying to light cycle', it sounds like the ignitor is clicking. So, should I lean towards a module replacement of just an ignitor replacement?