Where might I find a replacement printed circuit board for a "CARGO HEAT" bay heating unit ? Anyone have an old one that the fan or heating element is burnt out that they might want to get rid of for a price ?
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I have also come to the conclusion that the relay board in my heater is bad. I hooked the leads from the heater to a 12 volt battery and the heater won't come on. If I hood directly to the leads on the resistance heater it will work. I never could find a snap disc, so I thing the circuit board has a temp sensor built in.
2006 Monaco Diplomat
I found the snap disc. The wires were not connected. I connected the wires and now the "on" light on the control panel glows. The heater still does not come on. With a meter I get 13 volts between the 10 ga white and black wires at the molex connector. I also get 13 volts between the 10 ga white wire and the 14 ga blue wire at the molex connector. I think this is telling me that everything in the coach is good and I have a bad circuit board in the heater. In a previous test the heating element would work if disconnected and direct wired.
Any ideas from anyone?
Tony
2006 Monaco Diplomat
I believe the most common failure is the thermal fuse inside the heater. When it fails, 12V will not get to the heating element. You can test the fuse by putting an ohmmeter across it; no continuity = the fuse is broken.
When I tested my heater, the fuse was OK. I was able to buy spare/replacement fuses on eBay. Here's the link.
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Mark 2008 Holiday Rambler Admiral 30PDD (Ford F-53 chassis) 2009 Honda Fit Sport
I found the snap disc. The wires were not connected. I connected the wires and now the "on" light on the control panel glows. The heater still does not come on. With a meter I get 13 volts between the 10 ga white and black wires at the molex connector. I also get 13 volts between the 10 ga white wire and the 14 ga blue wire at the molex connector. I think this is telling me that everything in the coach is good and I have a bad circuit board in the heater. In a previous test the heating element would work if disconnected and direct wired.
Any ideas from anyone?
Tony
2006 Monaco Diplomat
Tony,
Does the fan inside the cargo heater run? Usually the fan runs and there is no heat. The most common failure causing that is the thermal fuse inside the heater is open. There are two lamps on your control panel associated with the system heat. One illuminates when you turn on the system heat switch but the second one only illuminates if the system is energized by the snap disk. I have included a schematic of the system heat on your coach that may be helpful.
Bob
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Bob and Pam
2022 Quantum JM31
2023 Colorado Z71
I took the heater out and found a wire disconnected on the circuit board that I hadn't noticed earlier. The fuse checked out good. I replaced the heater and it worked, fan and resistance heater came on as well as the indicator "on" light. Now, let's see how long it will run before the fuse opens.
Thanks for the responses.
Tony
Hi folks. I'm going to piggy back on this thread to ask: will the light on the control switch come on if the heater is defective ? My light will not come on and the heater does not work.
Thanks for the information from everyone. From my reading of the schematic, why can't the printed circuit board be eliminated and let the step switch operate the heater ? I'm thinking that maybe the step switch might not be rated high enough to handle the amps to operate the fan and the heat load. It seems that the step switch is only controlling a relay in the printed circuit board to turn the heater on, not to use it as a switch. Maybe put a 12V rated thermostat to turn on @38 degrees and off @55 degrees when the control board switch inside the MH is flipped on.
Does the fan inside the cargo heater run? Usually the fan runs and there is no heat. The most common failure causing that is the thermal fuse inside the heater is open. There are two lamps on your control panel associated with the system heat. One illuminates when you turn on the system heat switch but the second one only illuminates if the system is energized by the snap disk. I have included a schematic of the system heat on your coach that may be helpful.
Bob
Mine stopped working from the start. I pulled the guts out of the case and put in a Walmart 200w 120v heater. I used a thermal breaker in line. Comes on at 35 degrees. Don't trust this piece of junk.
Mine stopped working from the start. I pulled the guts out of the case and put in a Walmart 200w 120v heater. I used a thermal breaker in line. Comes on at 35 degrees. Don't trust this piece of junk.
Way ahead of you. We installed two small 120 VAC cube heaters about 8 years ago connected to the block heater circuit. We still have the 12 volt cargo heater and left it in place for those times when we are driving in cold weather without the generator running. That is not often as we run the generator most of the time.
Bob
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Bob and Pam
2022 Quantum JM31
2023 Colorado Z71
Jim,.
The switch light will come on when you switch it on. The indicator light next to it will come on when the snap disc has closed. It should close at 40 degrees. The indicator light will come on even if the heater is not coming on.
Tony
2006 Monaco Diplomat
I have been attempting to trouble shoot my wet bay heater as well. I get 14 volts at the molex connector for the black wire which I suspect runs the heater element. No power on the red wire which I suspect provides the snap disk power. I have not been able to locate the snap disc thus far. I did take the heater apart and confirmed the fan and heater element both work. I have power at the control switch which lights up, but the system heat indicator never illuminates. The thermal fuse in the heater is good. Does the 1" x 1" black circuit breaker/fuse on the heater element board come off? I can't confirm if this is good and don't want to try removing it if it's soldered in place. I've narrowed the issue down to this fuse, or the snap disc wherever it's located.
It sounds as if your heater will work correctly once it gets the activation signal from the snap disk.
You should be able to find the snap disk in the wet bay, somewhat near the heater. Trace the wire bundle back from the heater and investigate its "branches." A gentle opening of the plastic loom around the wire bundles can help you trace the activation wire into adjacent bundles until it leads you to the snap disk.
One you find the snap disk, disconnect the wires and jump them together. Turn on the system heat switch. The heater should go on (fan and element). If they do, and the "System Heat" indicator light does not go on, you may have a failed indicator light. Put the wires back on the snap disk, cool the disk to freezing, and see if it activates the heater. If not, you may have a failed snap disk.
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Mark 2008 Holiday Rambler Admiral 30PDD (Ford F-53 chassis) 2009 Honda Fit Sport
I have been attempting to trouble shoot my wet bay heater as well. I get 14 volts at the molex connector for the black wire which I suspect runs the heater element. No power on the red wire which I suspect provides the snap disk power. I have not been able to locate the snap disc thus far. I did take the heater apart and confirmed the fan and heater element both work. I have power at the control switch which lights up, but the system heat indicator never illuminates. The thermal fuse in the heater is good. Does the 1" x 1" black circuit breaker/fuse on the heater element board come off? I can't confirm if this is good and don't want to try removing it if it's soldered in place. I've narrowed the issue down to this fuse, or the snap disc wherever it's located.
Mike,
I believe the 1"x1" black square you refer to is a relay that activates from the snap disk and applies power to the heating element. You should be able to test the heater by using the procedure suggested by Mark in the previous post. The snap disk can be almost impossible to access. On our coach it is high up behind the white panel and attached to the frame rail. If I thought my snap disk was defective I would purchase another one and mount it in a more accessible location. On our coach the white panel must be removed to get to the snap disk. Not an easy task.
Bob
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Bob and Pam
2022 Quantum JM31
2023 Colorado Z71
Linear Mode
