suggestions for troubleshooting Hawk electrical problem?

[NRVhawk]

I'm looking for suggestions and advice on troubleshooting the electrical system in my 2016 Hawk. None of the 12V appliances (lights, fans, fridge) work when the camper is disconnected from shore power, even though the master kill switch is on (pulled out). They do work when connected to shore power.

This started after I removed an old PWM charge controller and replaced it with a new MPPT controller. To make the controller install easier, I took off the front face of the cabinets on the driver's side (I have a front dinette model, so the battery compartment and related electronics are all on the driver's side). To take the front face off, I disconnected the thermostat and the switches for the flood lights, reefer fan, and interior floor lights.

After installing and connecting the MPPT controller, I reconnected the battery and pulled (turned on) the silver master switch - but no 12V power. As I noted earlier, when I then connected shore power, interior lights and fans then came on.

The LiFeP04 battery was about 80% charged before I disconnected it, and the Voc is 13.3V now, so it looks okay. The MPPT controller LED lights up, so it's getting power from the battery. The kill switch appears to be working - I put an ohmmeter across the terminals, and resistance went from zero to infinite as pushed the switch in. However, the mechanical movement of the switch has never been very smooth, and sometimes I have to try to pull it a couple times. There's no voltage at either terminal on the kill switch.

There's no battery separator - I discarded that when I installed a DC-DC converter. However, there is a thermal fuse which I believe is in-line the battery output (red wires on it). That fuse is not open.

Any suggestions of what to look for next? I keep thinking I'm overlooking something simple...

 

[pvstoy]

It is usually the last place you were working either a pulled-loosened wire or shorted out a fuse.

Since there is no battery voltage to the kill switch you'll need to hand trace the positive from battery to kill switch. Also you'll need to hand trace the ground wire the same. I would suspect a hidden wire disconnected.

The inside light etc. are happy to run off the Iota as you can or not have the kill switch pulled. But the battery will not charge without the kill switch pulled out.

 

[NRVhawk]

It is usually the last place you were working either a pulled-loosened wire or shorted out a fuse.

Since there is no battery voltage to the kill switch you'll need to hand trace the positive from battery to kill switch. Also you'll need to hand trace the ground wire the same. I would suspect a hidden wire disconnected.

The inside light etc. are happy to run off the Iota as you can or not have the kill switch pulled. But the battery will not charge without the kill switch pulled out.

Thanks for the suggestions. Yes, it's easy to accidentally disconnect a wire when working around lots of wires in a tight space. Sometimes my hands feel like bulls in a china shop. I'll start tracing wires tomorrow.

 

[K7MDL]

Shore Power AC to DC power/charger output is on the load side of the kill switch. Since that works, the problem is now limited to a relatively small number of wires. Battery to kill switch, kill switch to dist panel.

What happens when you hook the camper up to the truck alternator and run the engine? That is another path to the kill switch. Do you measure voltage on either kill switch terminal then?

The truck side cabling comes in to the isolator *which you have removed) to a breaker then to the battery. On mine, there is a short #10 white wire from the battery side of the breaker or isolator that runs into the cabinet to the kill switch. I also have a front dinette. My bet is that white jumper is disconnected, hence no battery to the load and likely no alternator power to the loads either. The alternator would still charge the battery in this scenario..

 

[NRVhawk]

Shore Power AC to DC power/charger output is on the load side of the kill switch. Since that works, the problem is now limited to a relatively small number of wires. Battery to kill switch, kill switch to dist panel.

What happens when you hook the camper up to the truck alternator and run the engine? That is another path to the kill switch. Do you measure voltage on either kill switch terminal then?

The truck side cabling comes in to the isolator *which you have removed) to a breaker then to the battery. On mine, there is a short #10 white wire from the battery side of the breaker or isolator that runs into the cabinet to the kill switch. I also have a front dinette. My bet is that white jumper is disconnected, hence no battery to the load and likely no alternator power to the loads either. The alternator would still charge the battery in this scenario..

Thanks! Due to a change in schedule today, I wasn't able to get to the camper to check out your suggestions. I should be able to do that tomorrow, though. The camper is not on my truck right now, but I do have some old Atwood trolling motor connectors, so I'll work up a jumper from the truck to the camper to see what happens with truck power. Thanks again for the insights.

 

[K7MDL]

Sicne you do not have an isolator installed, you can just measure the voltage at the Attwood connector, should see the battery voltage on it assuming your breaker is closed (as normal).

 

[NRVhawk]

Sicne you do not have an isolator installed, you can just measure the voltage at the Attwood connector, should see the battery voltage on it assuming your breaker is closed (as normal).

Well, thanks to your suggestions, I tracked the problem down. As you pointed out, it was probably between the battery and the kill switch, and sure enough I found a butt splice that had pulled apart between the thermal fuse and the kill switch. Embarrassed to admit that it was a spice that I did a couple of years ago. Anyway, I replaced the splice, and tugged on it to make sure it wasn't coming apart. All the other electrical systems check out now. Thanks again!

 

[pvstoy]

Well, thanks to your suggestions, I tracked the problem down. As you pointed out, it was probably between the battery and the kill switch, and sure enough I found a butt splice that had pulled apart between the thermal fuse and the kill switch. Embarrassed to admit that it was a spice that I did a couple of years ago. Anyway, I replaced the splice, and tugged on it to make sure it wasn't coming apart. All the other electrical systems check out now. Thanks again!

Your welcome. Patrick
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