How to Handle The Smell of Hot Electrical Stuff While RVing

Almost every trip we learn something and have something new and different to fix. Multiple opportunities to learn new stuff.  Mostly minor stuff, but sometimes not.

On our last big trip, most everything worked perfectly until we started toward home. The chassis blower motor quit (in the Chesapeake Bay Bridge Tunnel). The weather had finally warmed up, and now we had no air conditioning. The next day the freezer temperature unexpectedly started to rise – and we found we were out of propane. We ended up running the Onan generator for two hours while driving to run both the coach air conditioning and the fridge.  Can't let the ice cream melt.

It was a challenge to find propane (thanks All Stays Camp & RV app), but we finally did (during rush hour of course). We figured our regular mechanic could deal with the blower motor when we got home. We stopped at a familiar campground and plugged in for the first time in 10 days. The Progressive Industries power monitor said the shore power was good. Time to walk dogs and have a relaxing hour before dinner.

PD upgrade to Magnatek

The area left of the circuit breakers was HOT.

But 40 minutes later, Lynn asked, “What’s that smell?”

“I don’t smell anything… smells like hot electrical stuff!

After sniffing around trying to find the source of the odor, Lynn opened the converter door under the bench seat on the driver's side of our 190 Popular Roadtrek. “Ouch!” The inner panel was quite HOT. We unplugged and let things cool. Lynn removed the brown door and front panel exposing the converter electronics at the bottom. Wow, was it dusty, but everything looked okay. We plugged back in briefly to run the microwave for dinner, and confirmed that the two fans in the converter were working. And nothing got hot. And it never did again. But we left it unplugged overnight. Back home we vacuumed out the dust. And we got the Dodge blower motor replaced. We plugged into shore power to test and all seemed okay – no hot converter, no mystery smells.

Converter Electronics

Converter Electronics (on bottom) was fine – this is PD4635 upgrade to the original Magnetek – has front & rear fan.

Fast forward one month. At the end of May we plugged into our home front porch GFI electrical outlet (as we had many times before) and turned on the fridge on electric to pre-cool it before heading out for Memorial Day. We discovered in the morning the fridge was not cold. No power to the Roadtrek. The porch GFI outlet had tripped, shutting off all power to our camper. It never did that before. Oh well, switch to propane. When we reached our destination we plugged into shore power. Started the microwave to steam veggies for dinner and it ran about 30 seconds and stopped. We found the GFI outlet in the kitchen area of our camper tripped. Checked the converter. It was staying nice and cool. Tried again and the GFI would trip instantly. We plugged the microwave into an outlet on a different circuit and it worked fine.

We know that old GFI outlets sometimes fail. This one was 20 years old. So, back home, Roger bought a new GFI outlet and installed it. Did that fix the problem? NO. Not on your life! Trip after trip of various GFI outlets — the one on our porch and mystery shut-offs of several of our 120 VAC circuits. Round up the usual suspects! It seemed like a two-way or maybe three-way problem. We checked and rechecked. Another outlet in the garage tested OPEN GROUND with our 3-light outlet tester. (The plot sickens.) We finally traced that to one outlet in the garage.

14 - Fixing Onan Rusty Grounds

Neutral and ground bonded inside the generator

Then testing determined that if circuit 5 (the kitchen) and circuit 6 (the fridge) were shut off at the breakers, everything else worked. Turning either of them on tripped the GFI on the porch where we had plugged in. In desperation, Lynn contacted Jim, our local expert on Roadtrek matters. Jim says he is no expert on RV electrical stuff, even through he knows his way around home electrical things (and he can troubleshoot and repair an Onan better than most RV techs).

He explained that an RV is utterly unlike home wiring, and there is no “real” ground in a motorhome.  And there shouldn't be, since that happens when you plug into shore power.  And there needs to be one point (and only one) where neutral and ground are “bonded” (don't confuse this with “grounded”) and that occurs in the main electrical panel in the campground.  But when you are using a generator, that isn't there.   A generator has two wires and there is 120 VAC between the two. Which wire is neutral and which is hot? It doesn’t matter – pick one. And RV experts get into big fights over bonding neutral to ground or letting it float – and both sides have good reasons for their view.  Both Roadtrek and Onan say to bond the neutral and ground inside the generator, which is the way ours is connected. Somehow we had a short inside the converter.

Neutral Buss Block

Neutral bus block – got a bit hot, ya think!

Jim offered to get his Fluke multimeter and test a couple of things. Yes, please! We told him there were already two Flukes sitting in our Roadtrek, he could take his pick. Jim wasn’t in our Roadtrek much more than five minutes before he unbolted the top panel over the circuit breakers on our converter, “I found your problem!” We took a look and saw scorched electrical wires in the neutral bus terminal block. The last two inches of insulation was melted or discolored on every wire. The black insulator the bus block was mounted on was partially melted. Ground wires were discolored as well. But the hot wires going into the circuit breakers were in perfect condition. It was amazing that any circuits worked! He discovered the source of the burning electrical smell and hot panel face a month back, and the source of our odd electrical problems since then.

We discussed long and hard about the possible cause. There are some possibilities but we are still not sure. Wish we had one of those RV electrical experts around!  But after the damage is repaired, there is a lot of testing to do before the power is reconnected – we don’t want to fry anything again. We thought we knew a lot about the 12 volt side of our camper, now we have the opportunity to learn about the 120 VAC side! So, just remember anytime something breaks or goes wrong, any adventure is a new learning opportunity!




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  • MaineBob

    Looking forward to “the rest of the story”…. In the meantime, here is the link to the upgrades that the Red Rover folks made to their RT 190P electrical system: http://www.redroverroadtrek.com/EE.htm This may be the type of upgrade you want to do… once you find the cause…

  • Andrew Pierce

    I had a similar issue with my 1991 Popular’s chassis AC. I replaced my Dodge chassis blower, but it turned out my problem was the blower resistor behind the glove box, which is apparently something that wears out, and then the blower stops working.

  • Dan Beaton

    For some reason, I have had a number of blower resistor failures over the years. The way to tell it is the resistor and not the blower is to set the blower to max. That bypasses the resistors, and if the blower works, you know it is likely the resistor. (Could also be the switch, but much less common.)

  • Dan Beaton

    I wouldn’t be thrilled about that bonding connection. The surface rust nearby suggests there could be rust underneath the terminals. But what is holding them on? It looks like a rivet. Rivets pull tightly but don’t cut into the metal. It should be a good sheet metal screw with a toothed washer to get good metal to metal contact.