OK, continuing from post #17, we are going to now go behind the water heater and test power to the module board. This board of electronic wizardry will usually be partially underneath a plastic cover similar to this pic below.
It may be mounted to a frame member, attached with double-sided tape to the water heater itself, or just laying loosely on the floor or top of the water heater. It is up to the installer as to where to mount it.
When they are just laying on the floor or come loose from the double-sided tape, then the electronics can possibly get wet or short circuit on other things. It does happen, since one side of the circuit board is actually exposed, as you can see in the pic below with the tape on it. The wire connections can also come loose from the RV bouncing down the road.
You may also notice in the first pic of the module board cover, the orangish spark cable/wire coming out of it that goes to the electrode that we discussed earlier. It is also just on a push type connector to the module board spark ignitor, and you may want to make sure it is firmly connected as this wire can come loose either at the module board or the electrode.
Now looking at the proper schematic again for the Suburban model you may have (we are using a SWDE for this example)
You will notice that the red wire coming from the thermostats to the module board is our power wire. We want to use the multimeter and make sure we are getting the correct voltage on this red wire to the module board. If not, then we go backwards towards the thermostat, and see if we can find a wire problem.
You can also disconnect the module board from the wiring harness and also from the spark cable. You may need to remove it in order to check for possible burned spots on the board...or to also take it to a RV repair place, where they most likely have a module board tester that they can connect it to in order to make sure all of it functions as it's supposed to. You may have very limited arm space behind the water heater too depending on how you have to gain access to it (as each RV will be different). You may find it easier to disconnect the module board and remove it rather than trying to test it in place.
Here lately, Suburban has had a
bad batch of the boards from their supplier, and you may notice something similar to this on yours on the Q3 being burned. Also on the first pic below you will see the spark ignitor on the upper right with the its spade connection that the orangish spark cable connects to.
The module board will be the problem a lot of times if you are getting power to the board but not to the gas valves, or are having spark ignitor problems and/or the gas will not stay lit.... but I would advise having it tested if you don't find something obvious as in the pics above. Most RV repair shops will have a board tester, and you may want to see if they will test it fairly cheap. The actual replacement boards are less than $100, and there are actually other brands (called Dinosaur Electronics) that many use as a replacement.
Next, we will move to the spark ignitor/electrode
2011 Flagstaff 831 RLBSS
Linear Mode
