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Letter 11

Isuzu Trek Owners Infoletter #11

June 2003

Inverter Problem??

Jim (jwhit2 (at) wrote:  I was using a small vacuum cleaner, that turned out  to draw more current than the 1100 watt maximum limit for the Heart Freedom 10 inverter in my TREK.

After about 12 mins of operation, the inverter AC light went out and I lost AC power.   I checked the batteries, and they were down (less than 50%, or Weak reading).  So, I started the propane generator, and that restored AC power.

Jim wasn’t having any luck restoring power with the inverter so he contacted the manufacturer and they, according to Jim, “recommended what turned out to be an excellent repair service in Reno”:

Alternative Energy Solutions,
195 No. Edison,
Reno, NV
Telephone:  775 857-1157

They told Jim that his inverter was working just fine, so Jim went back to troubleshooting in the Trek and found that nasty GFI in the bathroom needed to be reset. He reinstalled the inverter (he promised he would write that process up for a future infoletter) and all is well.

 Editors Note: Boy, Jim, sorry for all the struggles with the inverter problem. Folks, if you are having a problem getting 110 v. power from your inverter, chances are great that the problem is in the coach electrical system and not the inverter itself. Here is how I would troubleshoot the problem:

Assuming you are not plugged in to shore power and generator is off, turn the inverter switch off, then back on. If the inverter light comes on:  Be certain that the GFI circuit breaker on the outlet in the bathroom is clicked in. (in the Trek, the bathroom GFI is responsible for 99% of the 110v power outages.  Those GFIs, like circuit breakers, get weak after lots of resettings. It is highly suspect for replacement if you have much more trouble.  Mine goes off at least once a trip and for no known reason most of the time).

  1. Check the circuit breakers on the panel under the bathroom sink.
  2. If the inverter light doesn’t come on. Reset the bathroom GFI anyway and check for power at an outlet (light may be burned out). If no power at outlets, try turning on the inverter with the camera switch on the dashboard instrument panel. Check for power at outlets. If still no power,
  3. Check that the two circuit breakers on the inverter are clicked in (in the Trek’s trunk). Check for power at the outlets after resetting the inverter switch in the galley. If still no power:
  4. Check coach battery condition. If ‘good’ or better, check DC voltage at inverter using the inverter’s ground source. If good, check AC output at inverter. If 12v.DC is good but there is no 110v. AC, it is probably time for the inverter to go see the inverter doctor. Note: using the above, you haven’t checked the inverter’s control circuitry (electrical message from coach to ‘turn on’), so before removing inverter from coach, I’d have this checked first or find out from the ‘inverter doctor’ how to do it and check it yourself).

Also note: remember the earlier infoletter that says check the trunk for evidence of water presence on or near the inverter from a water leak from the stop light just above the inverter. This WILL cause inverter problems. If the inverter isn’t working, check inside the inverter for evidence of corrosion or ‘smoked’ parts from water damage. Inverters that are mounted vertically are most susceptible to this problem.

 Oil Line Problem

Randy (rechols (at) writes:

.  Just north of Gainesville, FL on I75 smoke started to fill the motor home.  We immediately pulled off to the side of the road.  The oil light came on just as we turned off the ignition.  After getting everyone out of motor home I could see the problem was a massive amount of leaking oil.  With the worst thoughts going through my head the first thing I wanted to do was get off I75.  A FL State Trooper stopped and offered assistance.  He called a tow truck that arrived about one hour later.  In the Isuzu NPR owners manual they instruct the vehicle not to be towed with front wheels off the ground unless the prop shaft at the rear axle is disconnected.  First lesson – always carry a 17mm wrench (I bought a full set of Craftsman from Sears).  I did not have one, and the tow truck operator was missing his.  After two hours of looking, he finally found one at another shop.  I disconnected the shaft and secured it to the vehicle’s frame.  We were then towed to local RV dealer where he left us outside the gates.  Class B and frame lift tow truck had no problem towing us the twenty miles.  After we slept for a little bit, our family arrived to help us out and we began searching for our problem.  After refilling the engine with oil, we cranked the engine and could immediately see oil gushing from the oil line that supplies the turbo.  The metal oil line had cracked right at the flare at the end that is connected to the engine.  My brother in-law was somehow able re-flare enough to reconnect the line.  Reconnected the propeller shaft to rear axle and headed home.

I replaced the oil line and eyebolt.  Total cost $31.50.  Road Service covered the towing. Hardest part of repair was removing air intake in order to install the new line.

Editor’s note: from this it appears that it is a good idea, when checking the oil, to inspect for oil leaks or seeps, especially the external oil lines near fittings. Flashlight needed. Also, when calling for towing service, advise the tower to come prepared to disconnect the drive line…a 17mm wrench will be needed.

Transmission Note (also from Randy):

I also had problems with my transmission shifting out of the lower gears on our last trip.  The economy light was blinking and transmission would not shift so first thought was more electrical than mechanical.  Stopped, turned off ignition and economy switch waited a couple minutes and restarted. No problems the rest of our trip.  While on the subject does anyone have opinions on whether to run the transmission with economy switch on or off?

Editor’s note: I always drive with the econ lite on except when towing in city traffic. Any other thoughts on this, please write me and I’ll put it in the next newsletter. Anytime the econ light is blinking, it is trying to tell you there is a transmission control problem. Resetting by the above method or by the method described in infoletter #10 will solve most problems of this sort.

 Alternator bracket

Jeanne (mempro (at) We had a problem with our Trek. We were towed in GA. all our belts fell off. The mechanic said, the bolt holding the alternator fell off, and the bracket that held the alternator broke in 3 places, so he had to make a new one and re-install the belts. About 150 miles down the road, same thing happened again, only this time the bolt fell off, the bracket broke, and the belts broke, and the radiator hose let go. Road service sent a mechanic out to work on it on I-95. Needless to say $320. later we were back on the road. However about 150 miles later the dash lights went on if we went over 55 mph. so we crept to Richmond VA. My problem is finding a mechanic to work on this vechicle. Isuzu dealers won’t touch motor homes, the reason they say is they don’t have the wiring diagrams. Do you or anyone you know have the diagrams for the wiring or do you know where they can be found. We have a 94 Trek with I believe a 93 Isuzu engine.

And, in a subsequent email, Jeanne said: When we arrived in Richmond VA, we brought the Trek to be repaired at a garage that repaired trucks. He replaced the bolt on the alternator and used some lock-tite. Replaced the alternator bracket and we had him check the alternator, but he said it was fine so we did not replace it. We left and drove from Virginia to Connecticut no problems. Three weeks ago we drove from CT. to Michigan and are now back in CT. again no problems The more my husband drives the Trek the more he likes it. We also have a different Trek, no magic bed, but a queen size bed in a rear bedroom, which is perfect for us as Gene had a hip replacement about 4/5 times and doesn’t want to climb.

Editor’s note: Boy, are these two Trek-rich!  We should be hearing from them twice as often!  Folks, Isuzu car dealers aren’t the place to go. Isuzu completely separates its car dealerships from its truck dealerships. What you need is an Isuzu truck dealership such as FMI in Portland. They know the Isuzu truck well and that’s what you’ve got…an Isuzu NPR truck chassis. Thanks, Jeanne, for pointing this out…that is how we all learn…from contributions like this.  Check your alternator bolt and nut for evidence that it is loosening up…might save us Isuzu Trek owners some time and money!

 Editor’s Note: We had a similar problem with our genset but we were luckier: intermittently, the Onan would crank and start but quit instantly when the start button was released. When it did start and run, voltage would be erratic but within limits. We were in Mexico at the time so internet research found two Onan service facilities with email addresses. Emails to both got the same response: “95% chance it is a bad voltage regulator” so I had a friend bring one down (didn’t know about the cheaper source Ken mentioned then, darn it!). The voltage regulator is a “plug-and-play” item. Just remove the cover on the genset, find the readily accessible VR plug, unplug the old one, plug in the new one, stuff the new VR in the available space (no serious need to remove the old unit), and our genset is back to providing great service.

 GeneratorKen (kencathyha (at)  writes:

Dale –

Since we saw you in Baja we have been on the move.  We spent the summer in Alaska, did a rally and Habitat build in Kansas, toured along Costa Esmeralda east of Mexico City and then went out west for a rally in Indio and on to Death Valley.  We plan to attend the first southwest Trek Fun Club rally in Happy Jack, AZ, in June and the pre-rally in Buffalo, NY, this summer.  Along the way we hope to do a Habitat build in Taos, NM, and another one north of Buffalo in Canada.  Below is some information/text on the Onan generator problems for the next Isuzu Trek bulletin.  Hope to see you down the road sometime.  Ken & Cathy

Fun and games with the Onan generator. My 94 Trek has the 3600 LP Microlite, model 3.6KY-FA/26120B generator.  The “B” stands for specification B and it is important that you have the correct model and serial number when talking to service and parts personnel.My generator problem started about three years ago.  On very infrequent occasions, after  about one to three minutes of generator operation, the microwave would start humming very loudly and the lights would get very bright.  When I looked at the auxiliary voltmeter it would be off scale with high voltage.  I would immediately turn the generator off, wait a couple of minutes and then restart the unit.  Sometimes it would be ok on the next run and other times I would need to cycle it on and off two or three times before it would work properly.

The over-voltage problem was very intermittent and it could go several months with no malfunction.  Last summer after a few failures in Alaska I decided to take it to Cummins/Onan for evaluation.  Naturally it worked fine by the time I got to the Onan dealer.  I purchased a service manual so I would have sometroubleshooting information when it failed again.The next time the unit acted up I was in Tucson so I took it to a service facility where they hooked it up to a load bank and ran it under full load for over an hour.  They ran several checks but could not find a problem.  Before departing the parking lot of the facility I tried it one more time and discovered the unit would start but would not run after releasing the start switch. Back in the shop the troubleshooting showed there was now an open circuit in the brushes or in the rotor windings.

Operationally the way the system works is when you press the start switch to engage the starter relay, 12 volts are also sent via brushes and slip rings to the windings of the generator rotor.  If the circuit through the brushes and rotor is good, AC current will be generated as the unit starts.  The AC current will then be rectified  to DC, regulated, and sent to the rotor windings to continue the process of making AC current when the start switch is released.   If the brush and rotor circuit is open, the unit will shut down when the starter switch is released.

Due to parts availability and schedule problems I elected to return home and repair the unit myself.   After disconnecting the electrical and propane connections I used an axle jack to support the unit while the motorhome was on the ground.   I then removed the four nuts holding the top of the generator mounting bracket to the floor of the motorhome.  By carefully rising the motorhome with the leveling jacks and lowering the generator on the axle jack I was able to remove the generator.

Several special tools are needed to work on the unit.  I tapped the bosses on top of the engine crankcase so a sling could be attached to lift the generator.  The flywheel/cooling fan must be tapped so a puller can be attached.  A solid steel rod, 7.875″x.045″ is required to remove the rotor.  Upon disassembly and inspection of the generator I found a broken wire between the rotor windings.  The wire is unsupported for about 1″ between the coils and is subjected to centrifugal force. The plastic coil support below the wire was cracked and separated, adding additional stress to the wire.Checking with parts suppliers on the web I soon found that the parts manual or the spec. B generator stated the rotor and stator must be replaced as a set.  They also informed me that when the rotor fails, 99% of the time the regulator will be damaged.

Further investigation on the web and at the local Onan dealer showed prices to be about $344 for the rotor,  $369 for the stator and $258 for the regulator.   Dennis at Advanced Service And Parts (ASAP) 1-800-630-1230 quoted the best prices for parts but shipping was additional. He has an after-market regulator that costs about $80 less than the OEM unit and starters for about $100 less than the OEM.  Another option I found on the web were reconditioned MicroLite generators for about $1900 from Dwayne at 1-763-755-0034.  He buys test units from the Onan factory and used units from the dealer network and assembles them into reconditioned generators.  He does not replace rotors and stators as a set like the factory recommends and said he has had no problems.

I found new MicroLite and the newer model MicroQuiet generators available on the web and at my local dealer for $2,526.  Due to schedule constraints and the limited time (210 hrs.) on my generator I elected to buy the electrical components locally and rebuild the unit so I could get back on the road.  In retrospect and with more time I would seriously consider trying to replace only the rotor and use the after market-regulator to keep the cost down.

Editor’s Note: We had a similar problem with our genset but we were luckier: intermittently, the Onan would crank and start but quit instantly when the start button was released. When it did start and run, voltage would be erratic but within limits. We were in Mexico at the time so internet research found two Onan service facilities with email addresses. Emails to both got the same response: “95% chance it is a bad voltage regulator” so I had a friend bring one down (didn’t know about the cheaper source Ken mentioned then, darn it!). The voltage regulator is a “plug-and-play” item. Just remove the cover on the genset, find the readily accessible VR plug, unplug the old one, plug in the new one, stuff the new VR in the available space (no serious need to remove the old unit), and our genset is back to providing great service.


From Trek Traks on the web, 3-24-03, some good information for us about windshield replacement:  Cascade Auto Glass  has free mobile service, and have a lifetime warranty on the glass and labor . Excellent workmanship according to the contributor. They work with all insurances and will pay your deductible up to $250. Call 1-800-320-5358 to see if they are in your area. Their web is

Jamie Glazebrook of Coachglass in Eugene, OR will give you recommendations for reliable and inexpensive windshield replacement facilities for your area. You can reach Jamie at 8007147171. They know what kind of glass is required for all Treks and can even supply windshields with shadebands at the top.

Hugh (mcquic (at) writes,  on three subjects:

Isusu transmission:  The light that flashes on the dash is the econo lite. This lite, I was told, is used as problem indicator (depending upon the amount of flashes that occurs under test conditions by a tech) as well as indicating when the econo switch is on.  If you hear of anyone that has experienced problems in this area, let me know.

Cruise control: I lost the cruise control about 20 thousand miles ago- would like to know if anyone knows where and what to start checking.

Editor’s Note: can we please have some contributions about repairing our cruise controls?  Send them to me!

Ceiling stains: I found that if you have stains on the ceiling from water damage they can be removed quickly by renting a rug steam-cleaning machine by using the hand tool, and you might as well do the rug while your renting the unit. (This applies obviously to those units that have a rug like material on the ceiling.)

Thetford toilet: I had to repair the Thetford toilet last year because the water fill paddle stop working.  Thetford people were a great help.  They supply a kit that allows you to retrofit both paddles at the same time.  About $65.00 for the kit. Removing the toilet was easy enough and it allows access to the repair area.

All for now…send me those Trek experiences you’ve had…Happy Trekking,