12 volt Thomas compressor

[Timaz]

I replaced my 12 volt Thomas compressor and now it won't come on. But my HWH air level panel shows us level when we're not...Now I have to find the level sensor underneath the coach. But I thought I should be able to turn on the compressor by holding the up button with the air pressure being down to 0?

[K7JV]

Be careful what you try with the level sensor. If your system is like the one on our '06 Dynasty, if you touch either of the adjustments (lateral and/or longitudinal) on the sensing board so much as once, it can be a very long road to happiness. There is no direct correlation between the compressor operation and whether or not the control panel is showing level. I may not be saying that quite right. Let me as a couple of questions.

Prior to your compressor replacement project, was the HWH showing the coach to be level when it was level, and not level when it was not? In other words do you feel that the level sensor was working properly before you tackled the compressor problem? If so, I would not do anything to touch the level sensing system.

Our compressor unit has an in-line fuse, at the compressor. The incoming cable on our unit has a red and a black wire. The red wire should be +12 volts, and should be always hot. It is the one that would have a fuse in the line, if you have a fuse there. The black wire comes from the HWH control box and tells the compressor when it needs to run. You should see +12 volts on the red wire, and the compressor should only run when +12 volts is present on the black wire. You could test the compressor installation by momentarily jumpering between those to terminals to put +12 volts on the black lead, and the compressor should run. If it does, then the problem is either between the compressor and the control box, or with the control box, itself as it would indicate that the needed control power is not getting to the compressor. If it does not, then the problem is with one of the devices on the compressor unit.

I don't know if any of that will help, but it might be a start for your to start troubleshooting. Truly, if your coach was automatically leveling to your satisfaction before the compressor project, I would not do anything to touch the sensing system on your control box.

If you do want to look at the control box, it will likely be mounted to the bottom of the "floor" of your coach in one of your basement bay ceilings. It may or may not be readily visible without removing a ceiling panel or cover.

[Timaz]

Thank you very much Jim. That should get me there.