91 U300 Bulkhead and AC Questions

Topic: 91 U300 Bulkhead and AC Questions (Read 3023 times) previous topic - next topic - Topic derived from Coach Build Numbers

91 U300 Bulkhead and AC Questions

August 27, 2015, 05:09:32 pm

Hi- I'm a 'newbe' here to the forum, we just bought a '91 GV Unihome U300 at an auction last week, and thought I would post a pic of our build plate with the vin and build number, but I don't see how to upload a pic with this post? Anyway, our build number appears to be 3807 and our Vin is 1F97D4409MN054235 and the build info line in full reads G91380740SBIU3006V.
Our coach has 101,700 original miles, it is fairly clean, some wear in the cloth upholstery, the tires are 90% good, it had 3 new batteries, runs well, it even had 1/2 tank of fuel! It appears the previous owners from SW Idaho donated it to a children's charity in Denver, Colorado which then put it in an auction near Boise. We had been looking for an affordable diesel pusher with good basement type storage, and we ended up with this coach after the auction was over. After all the dust settled and we had the tires rotated around, paid the Oregon DMV for the privilege of having Oregon state plates, and paid the Good Sam insurance for 6 months, we were about $10,300 lighter in the wallet area! I hope this was a good deal, it seems to be anyway!
But reading about the bulkhead separation issues has me concerned, is there an easy way for a newbe to spot any issues?
Another issue that has me puzzled is that there is no 120V power to the front part of the coach, from the bathroom forward, but just for the plugs. The 'fridge has power, the front roof A/C unit has power, etc. Someone removed the breaker switch from the breaker box for the circuit that powered the plugs, and I cannot even find the wire that should be hooked up to it. I spliced in a temporary power cord to check the plugs, but it blows the breaker when I apply power, so there must be a direct short somewhere. But other then the fading carpet, some wear on the couch and lounge recliner chair, and some water staining on the paneling below the driver's and passenger's front side windows it appears to be a sound coach. Oh, and I can't get the horn to work even with good fuses. Shucks, I was looking forward to those air horns! Anyway, I look forward to being a member of this forum and learning a lot of good things about Foretravel coaches.

Re: 91 U300 Bulkhead and AC Questions

Reply #1 – August 27, 2015, 07:49:40 pm

Hi dburt:

Your '91 coach is very close to our '91 GV 40 number 3772. The front outlets are also powered by the inverter (when on) through an inverter transfer relay. I'm thinking someone (possibly with less than adequate electrical skills) has attempted make some changes that have now rendered the front outlets in-operative, and it sounds like with a direct short. You will need to do some trouble shooting and eliminate things until you find the source of the problem. I wouldn't think the original wires are gone, maybe just tucked away. Good luck, post as you work on this and any questions you have.

Re: 91 U300 Bulkhead and AC Questions

Reply #2 – August 28, 2015, 04:23:45 pm

@dburt Welcome to the club. You're in the right place.

First thing I would check it the DOT dates on your tires. Doesn't matter that the tires have 90% of their thread. If they are older than 5 to 7 years (that number is open to discussion) you will need to replace them. RV tires rarely wear out they almost always date out.

When I got my coach the tires looked great. After I blew a rear tire about a thousand miles later found out they were 10 years old! I was lucky. It was an inside rear and it just went flat. It didn't disintegrate and take out the wheel well fiberglass. Was able to limp to the next town at 20mph and had all 6 tires replaced. You might not be so lucky. If a steer tire goes you are in for an exciting ride. Don't put yourself or your family at risk.

Edited to include link to how to read DOT date codes.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=11

see ya
ken

Re: 91 U300 Bulkhead and AC Questions

Reply #3 – August 28, 2015, 05:28:48 pm

Quote from: dburt – August 27, 2015, 05:09:32 pm

Oh, and I can't get the horn to work even with good fuses. Shucks, I was looking forward to those air horns!

Try this thread for some more ideas on fixing the horn;

Horn won't work

Re: 91 U300 Bulkhead and AC Questions

Reply #4 – August 28, 2015, 06:04:31 pm

I have a 91 also Build 3811 what your floorplan?

Re: 91 U300 Bulkhead and AC Questions

Reply #5 – August 28, 2015, 06:08:28 pm

Thanks Ken for the tire advice- I took the coach into the local Les Schwab tire store (a chain of tire stores out here in the west) where I get my tire work done, and had them look over my tires. There were two good Toyo tires on the rear on each outside with some nice looking Kelly tires on the inside, and some nice looking Kelly tires on the fronts. But on further inspection we found the DOT manufacture's date as putting the Kelly tires at 12 years old, and the Toyo tires at 8 years old. Since the Toyo tires were almost 'as new' we switched those to the steer tires, and put all the Kelly tires in the back. I don't have the funds for new tires right now (at Les Schwab the Toyo tires are about $500 each) but that is a priority for me, since I know the issues with outdated tires. I also bought a good Toyo spare and had them mount it on a steel rim so I would have a spare for the front in an emergency. The steel wheel cannot fit on the outside on the back axle because of the tire studs that are used with the aluminum wheels unless I want to carry a set of extra studs. My main goal was to have a spare to 'get to town with' if we should lose a steer tire. Sort of like insurance, if you don't have it you will need it, but if you have it likely you won't need it, hopefully!!
My coach has the side bath and center hallway, and of course lots of closet space in the long hallway.
I got all the original books, owner's manuals, a lot of the previous owner's service receipts for work done, etc which I really like to have with a used RV. I just wish I knew what someone did to that one 120v electrical circuit that feeds all the plugs from the bath forward. I may just have to figure out a way to run some new romex and install a new circuit breaker in the main box, or somehow find the short circuit and repair it and put the whole circuit back online.
Stump, Chuck and Jeannie, thanks for the reference info on the air horn, I will get right on that and see if I can get the issue solved.
I want to try out that air horn!!
Another issue has cropped up- recently several times when going to start the coach cold after it has been sitting overnight, the check engine light and engine shutdown light come on and the engine will shut it's self off after about 30 seconds after it starts. Started checking and the engine oil is fresh and full. Cold engine oil pressure at idle is 45lbs, warm idle pressure is 25lbs. Air pressure was 90 or over. I'm thinking perhaps it could be an electrical issue, since all the large Interstate batteries (although new in April) have been having trouble staying fully charged, even though I turn off the battery disconnect switch, and have looked for anything left on that could run the batteries down. But the engine crank battery is (according to the books) isolated from the house batteries, and if I put it on a separate battery charger and charge it up to 100% or about 12.7 volts the check engine light and shut engine down light does not come on and it starts and runs fine. Perhaps an issue with low voltage to an engine or fuel injector controller due to low battery voltage? The first time this happened I was not near a plug in for the battery charger, so I fired up the gen-set and let it run a couple of minutes and then tried to start the main engine again and presto!- it ran fine. So that made me think low cranking battery volts effecting something in the engine computer type controls?
Also, I am suspicious of the onboard battery charger- I need to check it's operation more closely and see if it is in fact fully charging the batteries when the coach is plugged in.
I sure do appreciate everyone's help, and I have found much useful information just cruising the different threads!
This sure does look to be a good forum with even better folks onboard! Thanks again folks- Dennis

Re: 91 U300 Bulkhead and AC Questions

Reply #6 – August 28, 2015, 06:15:17 pm

I forgot to add that I did find the posts on how to check the bulkheads, and with much worry and foreboding I went out last night with a good flashlight to check the rear and front bulkheads. Much to my relief they look very good with only minimal surface rust here and there. I was one happy camper to find that out!

Now I'm hoping the tooth fairy tells the tire fairy that I've been a pretty good guy and to be sure and bring me about 4 new Toyo tires for the rear of the coach!

Re: 91 U300 Bulkhead and AC Questions

Reply #7 – August 28, 2015, 06:23:24 pm

Check the sight glass at the top of the radiator. The 6V92 has a coolant level sensor and will shut down if coolant is low.

Re: 91 U300 Bulkhead and AC Questions

Reply #8 – August 28, 2015, 06:57:04 pm

thanks prfleming for the tip, I checked the sight glass and it was showing 2/3 full and only 1/3 from the top! Back to the drawing board on that issue!
But I did get the horn issue solved after reading the thread on horn problems. I tapped on the horn relay on the back side of the dash, and took off the horn button and made sure there were no loose wires. Shazamm!

I know have an air horn!!

Re: 91 U300 Bulkhead and AC Questions

Reply #9 – August 28, 2015, 08:34:29 pm

Sometimes just solving one little irritating problem can make the whole day seem worthwhile!

Re: 91 U300 Bulkhead and AC Questions

Reply #10 – August 28, 2015, 09:02:22 pm

And the Hadley's are one of the most fun toys on the coach!

see ya
ken

Re: 91 U300 Bulkhead and AC Questions

Reply #11 – August 29, 2015, 07:55:05 am

Look for a GFCI outlet maybe a reset button has tripped causing you to lose feed to those outlets.

Re: 91 U300 Bulkhead and AC Questions

Reply #12 – August 29, 2015, 10:10:13 am

Check the GFCI next to the bathroom sink. The buttons may be brown, not the conventional red and white. Took me an hour to figure that one out when our outlets quit.

That failing, buy an inexpensive non-contact AC tester from Harbor Freight or Home Depot. About the size of a cigar, you just stick the little probe into the outlet and it will indicate if there is power there. See HD page at: Search Results for voltage tester at The Home Depot HF models get poor reviews as they may come apart but only $5

Pierce

Re: 91 U300 Bulkhead and AC Questions

Reply #13 – August 29, 2015, 06:22:52 pm

dburt,

Welcome to the forum. There's quite few Detroit Diesel coach owners here. They are quite proud of them and we have a lot of spirited 2cycle vs 4cycle debates. You'll find all the help you need here with all the experts and experience in all areas of your coach as I have being a novice on Diesel pushers Many parts can still be had from the factory even for these older coaches.

I would advise getting and oil analysis as soon as you can if there is no oil change history available. Blackstone Labs
For 25$ you will be able to check on the condition of your oil and overall health of your engine for signs of potential problems.

Also check for for codes both active and historical. Flip the dash up and on the mounted on the wall across from the steering wheel you should have the code reader for the DDEC II and Allison transmission. Turn the ignition on and flip the switch on at a time and you should see a series of flashing lights if any to get the codes. They will keep repeating until you turn the switch off.

If there are no active codes causing a check engine light to stay on, you'll probably see only historical codes. A Pro-Link or some other diagnostic tool will be needed to clear them. Sometimes an event can can occur causing a code but may not be a problem and will stay in the historical codes until cleared.

Jerry

Re: 91 U300 Bulkhead and AC Questions

Reply #14 – August 30, 2015, 01:51:58 am

Thanks Jerry, and everyone else for the tech tips- I will start with checking the code reader and see if there are any codes, and report back on what I might find. Can a person buy one of the Pro-link code readers at a reasonable price to use to read or clear codes? I am somewhat of an old fashioned mechanic but electronic stuff can buffalo me.

Pierce- the first thing I did was replace the GFI plug in the bathroom as it appeared to be inoperative and I thought it might be the
cause of my problem, but it did not help. That's when I began to check around the breaker box and discovered that there was a missing breaker and no wire that seemed to lead to that circuit. Then I applied power from my shop to one of the plugs and it would just blow the breaker on that circuit in my shop, so it appears to be a dead short somewhere from the bathroom plug on towards the front, since all the plugs are dead, but I still have good power to the roof A/C and the 'fridge, since they are on a different circuit. If the coach still has an inverter, where would I look for it, and what would it look like? There is a box that looks like a battery charger hanging from the top of the battery compartment that has a fan on one end, it is not plugged into the 120v outlet that is next to it, and the cord is tied up like someone decided that the charger or whatever it is did not work anymore so they unplugged it. I can post a picture of it if no one knows exactly what that might be. It did not look like an inverter, or even a 120v to 12v converter, but perhaps that is what it is? I sure hate trying to figure out someone else's electrical work, especially when I can't figure out what they were trying to do, or if they even knew what they were doing!

Re: 91 U300 Bulkhead and AC Questions

Reply #15 – August 30, 2015, 09:19:49 am

The silver box in the battery compartment that is hanging is the battery/convertor charger,it should be plugged in so the batteries charge when on shore power. The power inverter is probably in the big bay open it from the drivers side and look towards the back of the entrance steps you should see it.

Re: 91 U300 Bulkhead and AC Questions

Reply #16 – August 30, 2015, 09:29:33 am

Quote from: dburt – August 30, 2015, 01:51:58 am

I sure hate trying to figure out someone else's electrical work, especially when I can't figure out what they were trying to do, or if they even knew what they were doing!

AMEN to that, Brother! You aren't the first new owner to encounter "custom" wiring mods, and you won't be the last.

Just for reference, here is a photo of the original battery charger/converter and the (separate) original inverter that came with our coach.

Re: 91 U300 Bulkhead and AC Questions

Reply #17 – August 30, 2015, 12:16:47 pm

Dennis,
Here's some old posts on '91 converters with photos of OEM equipment: converter charger or inverter charger

Also that GFI in bathroom feeds outlets (through the GFI circuit) to the outside outlet, outlet in the basement, and I think an outlet in the kitchen sink area. Different floor plans will have slightly different wiring due to the outlet location changes in each. Looking at your VIN it appears you have an SBI floor plan.

Re: 91 U300 Bulkhead and AC Questions

Reply #18 – August 30, 2015, 12:37:22 pm

Looking under the dash this morning, I did not see anything that looked like I could read engine codes from. So I am including pictures to see if I missed something- sometimes I am so good at seeing the forest I can't see the trees if you know what I mean!

Also including a picture of the dash right after starting the engine this morning with the check engine lights on, it ran for about 20 seconds and then shut it's self down. The cranking battery, before starting it, was down to 78% this morning at 12.4 volts but it turned over quickly and fired right up. Still the lights came on and then engine shut down. I have my external battery charger on it right now, so when it gets to 100% and 12.7 volts, it should start right up and no lights should come on, at least that is what it has been doing the last few times I have encountered this issue.

The battery charger in the battery bay has a cord coming out of it that has one end taped up. I don't like that! (See photo) I guess I could plug it in and see if it works and charge the batteries when plugged into shore power. I will look in the bay nearest the step to see if I see the inverter and converter. I know there is a compressor in there that fires up and keeps the air pressure at 90 lbs when plugged into shore power.

Re: 91 U300 Bulkhead and AC Questions

Reply #19 – August 30, 2015, 12:56:02 pm

For some reason in my previous post I neglected to include the picture of the onboard battery charger, so here it is.

Also, in the previous post is included a picture of the monitor set in the mode to read propane, water, waste water, etc levels.
It only reads propane levels in the somewhat scrambled version, I don't see how to get it to switch to showing fresh or waste water levels. But the monitor or the system seems to be on it's way out, so might have to look into upgrading that system someday. It does show a passable B&W rear view in the rear camera mode.

I found the converter, but unless it is also an inverter it does not appear to have a separate inverter? I am wondering if some of the electrical gremlins and 'issues' are not somehow interconnected due to poor or faulty work done by the previous owners?

Re: 91 U300 Bulkhead and AC Questions

Reply #20 – August 30, 2015, 12:59:32 pm

Look at the last photo you posted. Just above and to the right of the big fuse block. There are two rocker switches on the top with vertical lables. With the ignition on, turn the switch for the engine on and count the flashes from a small bulb about a foot away. Usually will be just a bare bulb at the end of a couple of wires. Count the flashes and then compare to the codes listed for your engine or transmission. Codes should be here on the forum or PM as I have the list.

Pierce

Re: 91 U300 Bulkhead and AC Questions

Reply #21 – August 30, 2015, 01:02:20 pm

Here are the code lights.

Pierce

Re: 91 U300 Bulkhead and AC Questions

Reply #22 – August 30, 2015, 01:05:16 pm

And the codes in the PDF.

Pierce

Re: 91 U300 Bulkhead and AC Questions

Reply #23 – August 30, 2015, 02:08:05 pm

Could not find a small light under the dash that would blink, but discovered that when I had the ign key turned to on and switched on the engine rocker switch on the small block attached to the firewall, the check engine light would flash in different sequences. So perhaps that is the 'small blinking light' for this coach? Now I will look up the codes and see if they correlate to what I counted out in the blinking sequences.

Re: 91 U300 Bulkhead and AC Questions

Reply #24 – August 30, 2015, 02:14:22 pm

Dburt, Don't rely on the display in the backup monitor for accurate info on the battery state. Use a Good Volt Ohmmeter to read actual battery voltage at the battery terminals. A load tester is also a good tool to have, just because a battery shows 12 volts does not indicate the condition of it.
Keep asking , someone here will help you with a solution.
Gary B

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