Wow, here we go, this is complicated and lengthy, but you guys never fail me!Okay, fridge works on propane, but not on AC. Dometic RM7030. I don't know that it ever has as I've always boondocked and never have plugged in until now.Cooling unit replaced 10 years ago. Not a full timer.RV park tech got his meter out and told me that the "elements" aren't getting the proper voltage. Said the elements ohm out fine. Said to get a Dinosaur board. Got the new board, hooked it all up, and nothing. No lights on the eyebrow panel, nothing. I took a picture prior, texted myself with every jumper's position, etc.For grins, put the old one back in. Voila. (voila as in lights on the panel, LP fired right up, but still no elements working)Okay, fine, put new one back in. Nothing.I figure while I think about if I had a bad new board or not, I will just work on something non related, so I start the engine just to get the seals wet. While it is running I walk by the fridge and...the eyebrow panel is on!...... Uh. Ok. I turn the vehicle off, and they go off. What the hell?For grins yet again, I put the old one in, have the tech come over, and we comb every single connection and verify per, well, each other, and the instructions that I hooked the new board up correctly both times.Start poking around with a meter and the two main white and black wires coming in to the fridge to its white plastic 4 way screw-down type of connector bridge is only getting 6v.Now is this because the two 6v batteries I have are in series?I called dinosaur, man he knew his stuff, we multimetered all sorts of pins all over the place, and he said the old board shouldn't even be working on LPG even with just 6v, but it does. We were both stumped.All other 12v items on the coach work, as they always have. Okay guys, do your thing!Okay all, how do we even tackle this?

So the net of it is that you only have 6V at the fridge? Does it jump to 12V when the engine is running, or not? Do you have proper 12V power everywhere, or is it wrong everywhere?If the voltage is wrong everywhere, you probably do have the batteries hooked up incorrectly or have one that's bad or something similar. If it's good elsewhere, that oughtn't be the problem unless you have something connected "in the middle" of the batteries in series. There should be nothing connected there electrically other than the two batteries themselves.I would trace out the 12V power and ground wires from the fridge. One of them pretty much has to be going to the wrong place or have a poor connection somewhere. A good place to start would be to check the voltage of the 12V wire and of the ground wire with respect to a good chassis ground; if there's any noticeable voltage on the ground wire at the fridge, that shows that it doesn't have a good ground connection (though that may not be the sole problem).

Since you say all the other 12V stuff works, I would trace those wires back and see where they came from. If that's not possible, run new wires fro a reliable source.

When the vehicle runs, that 6v goes up to like 7.2. Maybe I can check the other known working things like water pump, see what their readings are.

Fix the obvious. Start at the batteries to find the 12 volts.Might just have bumped the switch by the door that turns off lots of stuff.The 6 volts could be a sneak path. Starting the engine pushes the voltage up to the working threshold of the circuit board but not high enougg to activate the relays it drives.

Check your voltage again at refer. Use a different ground source.Verify that polarity is correct.

Complicated fridge question, stay with me here... :\

DrewE
Explorer II
Apr 07, 2018
So the net of it is that you only have 6V at the fridge? Does it jump to 12V when the engine is running, or not? Do you have proper 12V power everywhere, or is it wrong everywhere?

If the voltage is wrong everywhere, you probably do have the batteries hooked up incorrectly or have one that's bad or something similar. If it's good elsewhere, that oughtn't be the problem unless you have something connected "in the middle" of the batteries in series. There should be nothing connected there electrically other than the two batteries themselves.

I would trace out the 12V power and ground wires from the fridge. One of them pretty much has to be going to the wrong place or have a poor connection somewhere. A good place to start would be to check the voltage of the 12V wire and of the ground wire with respect to a good chassis ground; if there's any noticeable voltage on the ground wire at the fridge, that shows that it doesn't have a good ground connection (though that may not be the sole problem).
ScottG
Nomad
Apr 07, 2018
Since you say all the other 12V stuff works, I would trace those wires back and see where they came from. If that's not possible, run new wires fro a reliable source.
nehuge
Explorer
Apr 07, 2018
When the vehicle runs, that 6v goes up to like 7.2.
Maybe I can check the other known working things like water pump, see what their readings are.
YC_1
Nomad
Apr 07, 2018
Fix the obvious. Start at the batteries to find the 12 volts.

Might just have bumped the switch by the door that turns off lots of stuff.

The 6 volts could be a sneak path. Starting the engine pushes the voltage up to the working threshold of the circuit board but not high enougg to activate the relays it drives.
enblethen
Nomad
Apr 07, 2018
Check your voltage again at refer. Use a different ground source.
Verify that polarity is correct.
Dutch_12078
Explorer II
Apr 07, 2018
Are there any wiring connections at the series jumper between the two 6-volt batteries? That could be a wiring error someone made at some point that's only feeding 6-volts to the fridge.
OkieGene
Explorer
Apr 07, 2018
Following this post with great interest.

Im curious what would happen if you disconnected the fridge power, and powered it from a different 12 volt power source, completely different from your RV. Go a ham radio 12 volt power supply, or a different battery? . If the fridge runs this way then you know for sure it's your existing wiring.
wolfe10
Explorer
Apr 07, 2018
Only way to get 6 VDC from two 6 VDC batteries wired in series is for wire feeding the refrigerator to be coming directly off ONE battery rather than for the ground from one and hot from the other.

Yes, this assumes the batteries are OK.

Would be too much of a coincidence for their to be exactly a 6 volt drop across wiring and connections.
dougrainer
Nomad
Apr 07, 2018
1. That RV park man is NOT a tech. Even a low skilled parts changer knows to ALWAYS check the DC voltage at an appliance.
2. A Control board CANNOT change the incoming LINE(AC) voltage, so that just shows that the Park Parts Changer does not know anything
3. IF you have 2- 6 volt batteries and the VOLTAGE at the refer is 6 volts, and you have 12 volts thru out the RV, That means you have just 1 wire at one of those 2 batteries that is ONLY connected to the Pos of the one 6 volt battery. That wire is going to the refer or maybe other appliances. Check your batteries and you should not have a SINGLE only wire to just one post on one of the batteries.
4. It usually takes a MINIMUM of 9 volts to activate the LP Gas valve on the refer, so it is amazing you had the refer working on LP at all
5. Have you changed the batteries or messed with them lately? That would be the reason you had a miswired battery. Doug
nehuge
Explorer
Apr 07, 2018
Thanks for all the inputs. The coach came with 12v battery setup (its a 1995 model). I may just take a seperate 12v battery source and hook it up to see how it behaves.

Like dutch said, perhaps its a connection at the series jumper. It is 93 degrees out here right now, (ya I know, in April)....and I'll get out to it once it cools off some.

I can put some pics up of the different connections as well.

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Complicated fridge question, stay with me here... :\

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