We have a Moen shower valve in our motor home and we are not getting any hot water. It has worked fine for the sence it was new. It;s a 2007

Assuming that you have hot water everywhere else my thoughts are that you have a small bit of rust,sediment or other foreign matter in the control cartridge. It's possible that the scald guard feature of the faucet has slipped so it's not allowing hot water to get thru. Either way if you purchased this new moen will provide replacement parts free.If you are mechanically inclined you can perform these repairs yourself and save significantly.Last time I checked the cartridge,scald guard balancing valve are all one part and cost about ninty bucks. Prepare to be patient and call 1-800-BUY-MOEN. You will need the model number,approx. age and explanation of your problem.Good luck. Hope this is of some help to you. Thanks.P:S they will generally provide installation,adjustment instructions and trouble shooting tips if you ask.