2022 Heartland Mallard M26 Electrical Issue

Hello, and thanks in advance for any help. I bought a 2022 Mallard M26 on Saturday at camping World in Grand Rapids, Michigan. (Live in St. Louis) got home pulled into my driveway and the 15amp fuse instantly blows to the ac, none of the overhead lights works, radio. I’m thinking there is a short somewhere. Call technical assistance line for camping world and I’m told need to take it in for a tech to diagnose it. Unfortunately they can’t get me in until July 22. Is there anything I can look at or try to diagnose the issue?
 

david-steph2018

Well-known member
Lights and radio work off of 12-volt, is the battery disconnect turned off? Also, near the battery should be a row of red circuit breakers. Some are auto-resetting and others are not. You can feel the breakers with your finger for the reset button. There should also be a main fuse near the battery, that may have blown.
 
Lights and radio work off of 12-volt, is the battery disconnect turned off? Also, near the battery should be a row of red circuit breakers. Some are auto-resetting and others are not. You can feel the breakers with your finger for the reset button. There should also be a main fuse near the battery, that may have blown.
It blows as soon as the battery is turned on. I think the lights run off the same circuit as the 15a fuse marked “AC” because the slide lights, bedroom lights, bathroom light and lower bunk lights work. Thanks I’ll check for the row of circuit breakers near the battery in the front. I’ll report back.
 
Checked fuses near the tongue only found one 30amp which was fine and then all these capped connections none were loose. Where else do I need to check?
 

Attachments

  • 50E2474E-C5BF-4433-91C6-18C12A3B2CDC.jpeg
    50E2474E-C5BF-4433-91C6-18C12A3B2CDC.jpeg
    2 MB · Views: 25
  • C5C20230-5E8B-4ECF-80E4-82BE6EA6778C.jpeg
    C5C20230-5E8B-4ECF-80E4-82BE6EA6778C.jpeg
    1.3 MB · Views: 24
  • 955926AA-D5A5-4DF2-8338-2622B93B5D56.jpeg
    955926AA-D5A5-4DF2-8338-2622B93B5D56.jpeg
    603.4 KB · Views: 22
  • AEAF29E5-098E-4320-AD54-A1589B3C02FD.jpeg
    AEAF29E5-098E-4320-AD54-A1589B3C02FD.jpeg
    1.2 MB · Views: 28
Last edited:

david-steph2018

Well-known member
Check your ground cables and make sure these are good and tight. If this is okay, then you will need to start checking all the connections in the AC. There should be a junction box in the AC, shut off power and check the connections in there.
 

cipwood

Member
Did everything work on your predelivery walk through?

What power source are you plugged into at home, are you sure it's an RV compatible power connection, no offence intended ? I've seen RV's plugged into a home dryer outlet and that doesn't work. A home dryer outlet is 220v and typically a TT is 110/120v only.

Also check the 2 - 40amp fuses in the power panel to see if they are blown.
 
Last edited:
Thanks for the reply. Everything worked on pre-delivery but they were plugged in on shore power. But everything worked with no issues. We pull away drive 6 hours and stop at a rest area to sleep. Got home and turned the battery on, I noticed that none of the interior 12v lights etc were working looked at the 40amp fuses and both were blown, Changed them both and they instantly blew. I looked at the battery cables and sure enough the grounded the positive cable vs negative. Switched them around and changed the fuses. 80% of the problems have been solved. But now the 15amp “a/c” fuse blows instantly. The kitchen overhead lights, radio and awning led lights, range hood light and fan don’t work. I suspect they are all on the same line. Don’t know if the reverse polarity messed something up. I tried the little reset button on the circuit breaker but still no power?
 

cipwood

Member
40 amps will blow with reverse polarity on battery cables. But the a/c is still powered by shore power only. Where are you getting the shore power at home?
Do you have a 30 amp service wired for an RV plug at home?

Again, no offense, but don't use an electric dryer outlet it's not compatible for RV shore power.
 
Last edited:
40 amps will blow with reverse polarity on battery cables. But the a/c is still powered by shore power only. Where are you getting the shore power at home?
Do you have a 30 amp service wired for an RV plug at home?

Again, no offense, but don't use an electric dryer outlet it's not compatible for RV shore power.
I tested shore power at a camping world location by my house. But I don’t need shore power to run interior lights or the radio right? That should run off 12v
 
Also I don’t get why the 15amp fuses blows instantly, I’m thinking there is some sort of short in the system somewhere.
 
That’s the strange part the 12v items not working I believe have something to do with the 15amp fuse labeled “A/C” that instantly blows.
 
I pulled the fuse panel off yesterday and tracked the 15amp “a/c” fuse wire to see if maybe the line was cut or screw ran thru it. Couldn’t fined anything wrong with the line.
 
Frustrating that I’m dealing with this on a brand new travel trailer that is less than two weeks old. I’m going to try calling the camping world in Michigan that I bought it from to see if they can call my local camping world to get me in sooner than July 22nd. If not, I have no other choice but to take it back 300miles to Michigan to have them diagnose/fix it!
 
Top