Norcold Fridge not functioning on 12v

[Stormy98]

Working through various issues on my new-to-me '98 Sportsmobile.
Searched the forums and couldn't find anything pertaining to my specific situation:

Norcold fridge (original from 1998) works on 110v but not on 12v. The green "on" light glows very dimly on 12v so it's getting some power but not enough to function. The wires on the back show 12v so it must be something internal. Opened the electrical box on the back and didn't see anything obviously amiss. There are two glass fuses in there and both are good.

One thing of note about the electrical system, the PO replaced the 2 12v batteries with 2 6V golf cart batteries wired in series but that doesn't seem to be an issue since the wires going into the fridge are reading 12v.

Any tips for diagnosing would be appreciated!

 

[RVflyfish]

I have a Norcold so I was curious. Found this thread on a boat forum.

The AC recently stopped working on my Astro. One of three relays might have been involved. So I found this YouTube video on how to test relays.

 

[Stormy98]

Thanks for the reply. I found that thread myself and am wondering about the relays. The YouTube video is very helpful, so thanks for that too. Removing the circuit board to test the relays will be challenging but seems like that's the next step.

I'm still wondering why the "on" light is glowing dimly with 12v applied. I figured that since a relay is either on or off, if it's not working then no voltage would get through at all. But maybe someone with more electronics knowledge than I could explain...

 

[Scalf77]

My first choice would be to check the ground connection for the 12 volt input.

 

[RVflyfish]

Definitely try anything Greg says before anything I send. He’s forgotten more about electrical than I’ll ever know.

 

[Stormy98]

Thanks all. What do I need to do to "check the ground connection"? I did put the meter leads on the red and white wires leading to the fridge and got 12v across them.

 

[1der]

Thanks all. What do I need to do to "check the ground connection"? I did put the meter leads on the red and white wires leading to the fridge and got 12v across them.

All that is needed to read voltage are a couple of strands of wire. Those couple of strands are not capable of carrying enough current which is what does the "work".

A poor/dirty/ corroded ground connection will provide a voltage reading but will provide poor ability to carry current. SNexeith a poor positive connection.

One way to check is voltage in the wires when the fridge DC is connected and running. Are you still getting 12 volts or has the voltage reading dropped significantly. If it drops significantly then you should check all connections all the way to the fuse panel, and further if needed.

 

[Stormy98]

Got it, thanks. I'll connect to DC only and turn on the fridge and check the voltage.

Not sure if this would have anything to do with it, but I'm also going to trace the cables coming from the batteries to confirm exactly what was done when the battery wiring was switched from parallel to series.

 

[Scalf77]

All that is needed to read voltage are a couple of strands of wire. Those couple of strands are not capable of carrying enough current which is what does the "work".

A poor/dirty/ corroded ground connection will provide a voltage reading but will provide poor ability to carry current. SNexeith a poor positive connection.

One way to check is voltage in the wires when the fridge DC is connected and running. Are you still getting 12 volts or has the voltage reading dropped significantly. If it drops significantly then you should check all connections all the way to the fuse panel, and further if needed.

Ray is spot on with his answer, when we are just measuring voltage a poor connection can read 12 volts fine. Unfortunately when used in a circuit where current can be drawn you can see a significant drop in voltage.

I always say check the ground connection first, because it is usually the forgotten connection, and also many times people will leave their meter on a ground bus bar (alligator clip) and just measure the 12 volt output, bypassing the actually ground going to the actual device.

But yes, the 12 volt connection could also be bad and provide the same result.

 

[Stormy98]

Tested the voltage just now with the fridge off and then on. Voltage is the same - 12v. Ground connection from the fridge to the frame of the vehicle is solid. Positive wire has a solid connection at the fuse box.

Should I continue checking the electrical system or at this point is it more likely something with the fridge itself?

 

[1der]

I have a troubleshooting manual but the file is too big to upload here.
Shoot me a PM w your email and I will send it to you.

 

[N147JK]

Should I continue checking the electrical system or at this point is it more likely something with the fridge itself?

Divide and conquer!:d5: At this point I'd test the fridge independent of the van's electrical system. Get behind the fridge and disconnect it completely from the van. Then connect a known good, stand-alone 12 volt power source. This will tell you which direction to go.

 

[Beaky]

we come from a pure overlanding setup with an FJ and an Aussie offroad trailer so we spent time working with offroad dedicated shops in SoCal. We are in the process of having our van updated with Redarc charging and management systems, upgraded inverters and wiring connectors. If you have electric issues most offroad shops can design and implement a modern fix.

 

[arctictraveller]

You say you are getting 12vdc, but what is the exact voltage you are reading?
12.0 is pretty much a dead battery. 12.5 or 12.6 is a fully charged battery after sitting with no load for a few hours. What is the exact voltage under load?
There should be no difference between the old single 12v battery and the two 6v ones in series.

 

[Stormy98]

Was reading 12.5v with fridge off and on. Pulled the fridge out this afternoon and connected it to a standalone LiFePo battery. Got 13.3v. Exact same performance with the LiFePo battery - no cooling and very dim green "on" light.

 

[1der]

PDF sent

If you need a thermistor, I might have a new one here. It was a pain to find it . I bought it then figured out what was wrong, it was not the thermistor - so never installed it.

 

[Stormy98]

Thanks, much appreciated. The guide you sent helped me search for a different guide that was printed around the time my unit was manufactured (model DE-351D, apologies to all for not including that detail in my first post):

https://www.yumpu.com/en/document/r...tekii-service-manual-299kb-bryant-rv-services

Will update with what I find.

 

[basssears]

Have you tried completely disconnecting the fridge from all power then reconnecting? I don't have any explanation for how it worked, but I had a newer fridge that suddenly stopped working on 12v (after I think a little weird power surge when I was running off a generator). In the process of diagnosing and checking wires (which is definitely a place to start 100%) I disconnected fully from power and when I reconnected 12v suddenly worked again.

Simple thing to try might just be circuit board or relay that is a little confused.

-- Bass

 

[bidgoodr]

We had a Norcold 3 way (AC/DC/propane) fridge in our 2000 VW Eurovan. It was terrible, and I encountered many other Eurovan owners who said the same thing. So we replaced it with a 50 quart ARB fridge freezer (AC/DC) model which ran great. When we sold the Eurovan in 2016 and replaced it with a 2017 Ford Transit we installed the exact same ARB unit which is now 7 years old and continues to run great.

 

[Stormy98]

Thanks for the suggestions. I did totally disconnect the fridge, let it sit, and then connected it to AC and DC. It works great on AC so it's clearly something along the DC path. Hoping to get to the diagnostics this weekend after I complete the replacement of the front Starcool fan (another story).