Water heater ECM location

[Desert RVer]

I'm trying to find the location of the electronic control module for the Water heater on a 2006 3400 RL. Removed the tan covers on the rear and front of the leg of the kitchen island and can see the rear of the water heater, piping and some wiring. But no module. Where is it located?

Gas water heater not working. Trying to start with spark igniter but gas solenoid not opening so no gas flowing. Checked voltage on solenoids and getting a very eractic voltage when the spark igniter is doing its' thing. Voltage so eratic no value can be determined. Have checked to make sure all grounds are good. Solenoids don't seem to be getting the right voltage and as far as I know that comes from the ECM but can't find it. Help???

[bw2]

I had the problem where the gas would not ignite. I pushed the reset buttons (there are two black buttons above the gas tubes), still nothing. Checked the voltages and found that the solenoids were not operating. This was the first use after de-winterizing, the electric had the water hot but I remembered reading somewhere the following; I shut off the electric, drained the water out of the water tank, about half, then let it refill with cold water. Pushed the reset buttons and then the gas ignited. I believe the high temp had gotten set/stuck, and this process allowed for the reset buttons to be pushed and reset the gas solenoid control.

Hope this helps

[2 Sinks]

Desert RVer- The ecm on our water heater is located on the side of the tank,I had to pull the basement panel under the shower pan area to access the water heater.Yours should be easier to get to being inside the 5ver.Our ecm was attached with a plastic tie strap to the tank wiring and touching the tank.It had a partial plastic cover on it and was under some insulation.The wiring to one side of the element & reset switches was completely burnt off !!! I replaced the wiring and several connectors and haven't had any problems since.I made the repairs in the Fancy Gap Virginia KOA campground.

Hope this helps.

[Desert RVer]

bw2,

I'm pretty sure your problem isn't the same as mine. The RV has been setting unused for several weeks with the water drained out of the water heater. My solenoids are not opening the gas valve but the voltage/current to do so comes from the Control module. The spark ignitor/starter voltage comes from the control module as well and it appears to be giving adequate spark to light the gas if the valve ever opened. That leads me to beleive I don't have a reset issue. I'm monitoring the voltage on the solenoids with a VOM and the eractic or pulsating voltage there seems to be kind of cooincident with the spark voltage. So, either I've had a control module failure or I've lost the ground to the contol module. But I can't find the location of the control module. The loose manual for this water heater shows it may be behind the outside RV wall requiring a complete or partial removal of the water heater to get to it. But before I try that I sure would like someone else with a 3400RL to verify that. Thanks.

[Desert RVer]

The voltage that shows up on the solenoid coils seems to be similar to what is driving the spark igniter. As far as I can tell it should be a solid 12V while trying to start and stay there once it is lit until the water heater reaches the appropriate temperature. The electronic control module gets 12 volts from the inside switch in the RV which tells the water heater to start. This 12v gets fed through a 12V Hi Limit and Thermostat protection switch to the ECM which then is supposed to send the high voltage to the igniter for the spark and 12V to the gas solenoid coils. I'm getting the three cycles of spark but the voltage that is being applied to solenoid coils isn't a solid 12V DC. Without adequate test equipment it appears that the pulsating high voltage that is supposed to only go to the igniter is also going to the solenoid coils. Or the 12V DC is being modulated by the pulsating igniter voltage. Possibly a wiring short or a defective ECM but I sure don't know where it is located for sure. I'd hate to pull the bezel off the water heater and start pulling the water heater out the wall and then find out the ECM can be accessed an easier way. I can maybe feel a box where it is located through the inspection hole in the kitchen island but cannot see it and feels more like a junction box. Surely there has been another MOC member who has been through this or watched a dealer replace an ECM. I've done a search here on MOC but have not observed someone saying where it was but have had them replaced. Even mentioned the ECM by itself costs $90 or so. Hopefully a fellow MOC'er will pop in here to help. It sure would be appreciated. TIA.

[2 Sinks]

Desert RVer- What brand is your water heater...Suburban ? The ecm on ours has to contact the tank for the thermostat sensors to signal turn on/off.The ecm/pc board on our water heater is aprox.3"x4"

I didn't find it until I started pulling the 120v feed wiring around the tank area.If your tank is styrofoam insulated the ecm may under it.

[Desert RVer]

2 Sinks,

Yes, it is a Suburban Model SW10DE. Thanks for the tip, I'll tug on some of the wiring and see if the ECM appears. The tank does seem to have a formed dark colored insulating cover around it. Not sure it is styrofoam though. I've also been searching on various RV forums and it does appear that the ECM should be behind the water heater and reachable(observable?) through one of the two inspection holes in the kitchen island. I'll try a few more times before I light the dynamite!

[Desert RVer]

I have finally found the ECM. Not where I expected it to be at all. I removed the whole inspection panel(below the shelf), rear of island facing the living room, to the left of the vacuum, that had an ugly inspection hole cut in it, That allowed me to see the whole water heater much better. The ECM was double side taped to the outer left wall in front of the top side of the water heater. Never would have found it w/o removing the whole bottom inspection panel. Looks ok, contacts look ok, but am cleaning them and trying again. Nothing burned or defective that I can see so far on the ECM. Will have to check to see if all the wires have continuity also. Do dealers have a way to check these ECM's with an in-house tester? Probably charge $50 to test it. Might just as well buy a new one if they are $90.00. Whoever installed this ECM sure didn't give any consideration to an RV owner with possible maintenance/failure issues. Would have had to pay $90 for a dealer tech to just find the ECM and stilll not know what the problem is. Thanks for the help so far.

[Desert RVer]

Cleaned contacts on ECM, re-installed but solenoids still are not energized during igniter cycle. It does appear that the ECM is switching the 12V but need to check the wiring continuity. Multimeter quit working while testing. Need to go get a new multimeter to do further testing. Lowest cost ECM I've found on the web is $99.99 for Suburban part number 520814. At the moment not sure if I have a defective ECM yet. But was getting 12 V switched output back to the inside switch indicator but not to the solenoids. That may be the real problem. If this is true I have a bad ECM. Will check again with better test equipment.

[2 Sinks]

Desert RVer - Glad you found the ecm.Those ugly access holes throughout are an option...mine came with the pieces of wood which were cut from the holes as well as all the saw dust/wood chips,skinned wire housings scrap wire and scattered scraps of building material all neatly concealed behind the panels.

Oh well...back to your water heater problem,possibly a dealer can check it,I don't know if they have that kind of diagnostic eq., or maybe they can try it (your ecm) on a unit there working on to see if it works correctly.As far as meters/vom I prefer a Simpson 260 and a Beckman digital.Keep us posted on your findings.

PS - I put dielectric compound on all the module/pc board pin connectors I service in our 5ver to prevent corrosin from our frequent ocean front camping.

[old turbo]

I just replaced the circut board on a Suburban SW6DC this past winter down in Texas. Turn your electric controls for the heater completely off. When you turn on your gas control to start the heater for gas only, you should hear a clicking sound from the circut board mounted on the hot water heater this could be on the top or side mounted. Some have duuble stick tape others are stuck under straping. If you do not hear the clicking sound it is a sure bet the circut board is bad. If you can get to thw circut board it is an easy out it is not screwd into anything. It should have a plug with three wires and a wire that goes to the solenoid. Take it out and double check that it is bad. It is easy to put back in mine was just stuck with double stick tape on top of the water heater. You can get the factory board or one called the Dinosaur board. I paid $109 for the Dinosaur. Factory board has one year limited warranty while the Dinosaur has a 3 year limited warranty. The little cover that just sits on the board will not fit the Dinosaur board but the cover is not important. This is the same circut board that operates most furnaces, water heaters and refrigerators, If you are interested in the Dinosauer board contact them at Dinosaur Electronics Inc. 1160 SE 27th St. Lincoln City, OR 97367. Phone No. 541 994 4344. Good luck

[Desert RVer]

Thanks ever so much for the reference to Dinosaur. Now this is a company that seems to know what quality is all about. Have a replacement multimeter now and will check things out tomorrow. I'm about 99% sure that I'm not getting the switched 12 Volts from the ECM to the solenoid coils. Everything else on the ECM is working. Will also check the solenoid coil resistance to make sure they are not open or shorted. I really like that the Dinosaur ECM adds an indicator light for the solenoid signal AND OFFERS THE 3 YEAR VS 1 YEAR WARRANTY. If only RV manufacturers would do the same. Here is the link to the Dinosaur web site:

http://www.dinosaurelectronics.com/

[Desert RVer]

Ok, Foud out I have two failures, one that caused the other. The ECM solenoid switch 12V drive wasn't working. Found burned up etch on ECM between relay and connector contact. Checked resistance of the two coils on the solenoids. One was a dead short and the other 40 to 50 ohms. The two coils are wired in parallel. The coil that is a dead short is what burned up the etch on the ECM. Fixed the etch on the ECM and disconnected the shorted coil. Now the other coil(solenoid) actuates when the ECM sends a signal to it. So right now the ECM appears fixed and I need to replace the dual gas valve. The Suburban manual isn't very clear on which one I need but appears to be Suburban part number 161109. The voltage that drives the solenoid coil is not a nice clean 12V and seems to be a bit unregulated. Don't know yet if that is supposed to be a solid 12V or not. Anyone know?

Anyway now know what the problem is.

[Desert RVer]

Have ordered replacement parts for the Suburban SW10DE water heater. 161109 Gas Valve ($81.38) and (ECM) UIB S Igniter Board ($84.95) made by Dinosaur Electronic. Even though I repaired the current ECM I didn't like the voltage quality of the switched 12V output. The new Dinosaur board has a replaceable 5 A fuse in the switched 12V output. And also an indicator on the board to display when it is working right and supposedly a better voltage regulator for the 12V output. Includes a three year warranty. I became concerned that there might be a chance that the old ECM might damage the new Gas Valve and therefore decided to replace both failed parts at the same time. I'll keep the repaired ECM as a backup spare. It did appear to me that the Gas valve's shorted coil could be easily replaced but didn't find anyone selling just the coil separately. I'll stop by a few RV dealerships over time and see if I can pick up a gas valve that has been taken off a RV. It probably will have one of the two solenoid valve coils that is still good. One can remove two screws and get to both coils for easy replacement. It seems a bit obnoxious that one cannot buy just the coils.

Should have both replacement parts in about three days. I'll report results when I get the new parts installed.

[Art-n-Marge]

Desert RVer, way to stick at it. I am looking forward to hearing that you resolved your problem. I like the way you've done the periodic status reports. Way to debug!

[Desert RVer]

WALA,

We have ignition and liftoff. Installed the new Gas valve and ECM today and now have a water heater working on gas fired again. $200 in parts and shipping costs, a couple hours of trying to locate the ECM, an hour more diagnosing what the real problems were and an hour to try to repair the old ECM. But decided to replace the original Suburban ECM because it didn't have a fuse in the switched 12V output and didn't like the signal quality coming out of the unit. I suspect this would have been a $500 to $600 dealer repair bill, maybe even more. Nothing really difficult once the ECM was found. The only other difficult part was removing the original brass 90 angle fitting from the old ECM so it could be installed in the new one. It was really in there tight. Had to try several different tools before finding one that would break it loose without ruining the fitting. A good multimeter is needed to measure coil resistance, trace continuity on the circuit board and verify voltage is getting to the right places. If you have the original Suburban ECM. it will blow out if either one of the coils chorts out. It burns up the circuit board trace from the relay to the connector doing what a fuse would have done if had been used on the original ECM. On the Dinosaur ECM there is a 5 Amp automotive fuse in this line and an indicator to show the ECM is switching properly. However, if the fuse blows one needs to find out why. Probably will be due to one of the gas valve coils shorting out. Why Suburban didn't use a fuse can only be explained by the fact that they maybe saved $0.50 on the original cost of the ECM and due to this will sell more repair parts because of it. A dealer probably would have charged at least $300 for the parts alone plus at least two to three hours of $90 an hour labor. But now I know where the ECM is located, how it is wired, how it all works and have a better and safer setup than the original from the factory. Life is good. But the real question is: Why didn't the original manufacturers do it right to begin with? I suspect the same setup is used on all RV's that use a Suburban Water heater no matter how much the original cost of the RV is! They need their butt kicked.