Rather than piggy-back on an earlier post, I'll start a new one with tag that may help future searches.
I've got a 2003 U320 4020 with the chassis batteries mounted behind the engine. If I'm going to attempt to jump start the engine where on the motorhome do I connect the jumper cables (yes--I know, not the $10 model) lol. Also, my temps are in the mid-40's, so I'll be running the generator to heat the engine prior to jumping. My boost switch does not seem to be working.
I actually have a perfect storm of several needs to address, but getting the bus cranked is my most immediate need.
Thanks!
Steve Rushing
I would put the cables on the chassis batteries.
Steve, on my 2001 U320, there are battery connections with red and black covers located facing rearward near the air dryer. Remove covers and connect jumper cables there.
I had to do that after we bought the coach as the PO had installed a new isolator but mixed up the cables and all batteries were flat. Our U300 has the engine/chassis batteries just in front of the rear bumper. I just hooked up the jumper to them, fast idled the toad for 10 minutes and it started right up.
I bought a HD set of cables and keep them under the seat in the toad. I've jumped a lot of people. Good karma.
Pierce
Thanks for the quick responses!
Rudy--I can't find the posts in the area you describe. They may be in plain sight, and I'm simply not recognizing them.
I'm going to try by connecting to the batteries--can just get underneath. I should be able to connect to the first battery I see (red/red, black/black)--correct?
Thanks!
Steve
Steve, sent you a PM
If a boost switch does not close the boost solenoid, just put your jumper cables on both sides of the boost solenoid to simulate the solenoid closing.
Or you could put 12v on small boost solenoid pos terminal to see if solenoid will close.
You could put jumper positive on boost solenoid side that is connected to start bank. Use any frame part for jump negative.
You can use the aqua hot to heat the engine.
While this will certainly work electrically, working with jumper cables in that tight an environment with so many ground sources (any metal) around with the extremely high amps available is NOT how I would do it. Instead, remove the wire from one large lug and ADD it to the other large lug. You have not electrically done the same thing-- created one large battery bank from the two separate ones. They will now charge and discharge together. So, one has to be more electrically savvy!
Agree, to prove the solenoid I have no problem disconnecting the small "signal"/positive wire and using any small gauge wire to go from the large "always hot" lug to the positive signal terminal. If the solenoid "clicks" and joins the two large lugs, you know the signal from the dash is not reaching the boost solenoid. If not click, the solenoid is bad.
Thanks for all of the suggestions! Honestly a lot of the info is currently (no pun intended) above me. Give me an old Ford 300/6 or Chevy 327 and I'm good to go...but this is my first diesel, and I'm still learning some of these parts along with their locations.
I did put a 15-amp charger on the first battery (did not remove the connections) and after about three hours it showed 100% charged. When I tried starting the engine did turn over slowly, but only for about five seconds. Then only blinking dash lights. (BTW--the engine had heated to 102 and the oil was at 60.)
I think my alternator may be bad, which is why the batteries are down. Two weeks ago I took the rig on a 100-mile run to make sure everything was good to go for a planned trip last weekend. Dusk set-in about 1/2-way into the trip, so the headlights were on...along with the radio and everything else on the dash. At the end of the drive I topped-off the fuel tank with the engine off, and parked in the back part of my driveway--about 85-feet from my 50-amp plug-in. Two days later, when I tried cranking it, the engine dragged, and then the dash lights blinked with the familiar buzzing sound you get when a battery fails.
Yes, the check engine has come on recently during a short 50-mile drive, but it wasn't on during the above 100-mile drive.
As I said perfect storm. I learned my boost doesn't appear to work, and also my aux air compressor isn't working. In both cases neither button lights. The compressor is another new gadget for me, but I know it was working back in the spring while I was at MOT having the rest of the rig serviced, and they replaced the 6-pack and some other items related to the air system replaced because the air compressor wasn't shutting off as it should have.
I'm going to put the charger on again tomorrow morning before I head to work. What I'd like to try tomorrow evening is a combination of the again-charged batteries, and jumper cables connected to my Ram 4x4.
Quick questions--
1) Is it possible I only charged the one battery to which the charger was connected?
2)Where is the boost solenoid?
I'll get to the alternator and aux air, after I get the bus cranked and moved back to my 50-amp pole.
Thanks!
Steve
When batteries show 100% but don't seem to put out the amps, it's time for a load test. If you separate the batteries, you can charge and load test to see if they or one is bad. Load testers are cheap. If the battery(s) are low, the alternator should put out in the 14 volt range. Flat batteries or frequently deep discharged batteries may not come back.
Another reason for two voltmeters on the dash and in your line of sight. Good to be proactive instead of on the defense when problems first start.
Ford 300/6 is a great engine. Used a lot in gas or propane generators where they can rack up thousands of hours without a problem.
Pierce
Pierce is correct. Fully charge the batteries and have them LOAD TESTED. Any place that sells batteries can do this in a matter of a few minutes.
While driving, what did the voltmeter on the dash show?
If you connected the charger to the positive and negative terminals of one of the 12 VDC batteries, then yes, both/all batteries in that bank would be charged, since they are wired IN PARALLEL. Yes, this assumes the battery connections are clean and tight.
Excellent point about the battery connections clean and tight. More than once, I have cranked the engine and then after starting, I've gone back to put my hand on the terminals. Several times, they have been warm, a couple of times too hot to touch. Good to take a second and pull then clean at least once a year. I like the green and red felt rings.
Pierce
When the battery doesn't get charged in a car or PU truck, the alternator always gets the blame (or in
really old vehicles, sometimes the external voltage regulator).
It's a bit more complicated in a RV with two separate battery banks.
Your problem might be the alternator itself. It could also be the alternator wiring (Excite wire broken/improperly connected).
Or your problem could be the battery isolator. It might be improperly connected, or it might have some kind of internal failure.
OR, as stated above, bad battery/charging cables or broken/dirty connections between cables and devices.
Check the other stuff first, before you run out and buy a new alternator.
Yes, if you THINK the alternator may be bad, it is very easy to diagnose that vs battery isolator.
All you need is a digital voltmeter.
Let us know and we can provide the easy steps to diagnose.
Just a note.. The boost "jumper studs" may have 2 rubber covers over them.. may not have them, I don't.
If your chassis batteries were flat, and they showed 100% state of charge after only 3 hours at 15 amps, your batteries are toast.
On my 03 there is a + and - post inside the side door that you would open to see the batteries and air conditioning condenser ( behind the drive wheel on the drivers side) . It is near the outside skin. There is also a + and- post on the right side of the motor if you open the engine rear door. Both can be accessed from the outside of the coach.
Keith
Thanks, all. Great info, and insights. I'm sure at some point there will some other newbies who can use all/some of this to their advantage. For those of us not versed in what, and where many of these parts are it can be a bit intimidating to reach out to those who speak motorhome. I've done enough shade tree on my old cars and trucks to know sometimes you just have to stop and ask.
It was cold and rainy here today, so I'm not crawling back under there until Wednesday.
In the meantime, there are a couple of points to highlight:
1) The lowest the voltmeter showed at any time was approximately 11.5. After charging it was showing just past 13.
2) My comment about the alternator was borne of not knowing more about battery isolators. I still don't know where this is located.
3) I haven't checked connections, yet. It seemed charging first might be the easier, "I hope this works" solution.
After more checking underneath on Wednesday I'll have more info on the state of the connections.
Thank you, everyone, so much!
Steve
On the forward wall of the engine under the bed. If you follow the big cable on the alternator forward you will find it. Splits and goes to the different batteries
Scott
Like Scott says, lift up the mattress platform and look down in the engine bay.
Should be a blue aluminum box with cooling fins. 3 posts. Center post is alternator input. Outer posts connect (probably indirectly - through the BOOST solenoid) to battery banks.
Link below to a post with photo. Ignore the Trik-L-Start (small blue, yellow and black wires). It is not standard factory equipment (but it
is a good add-on device).
TRICK-L-START Install How easy is it???? (https://www.foreforums.com/index.php?topic=9820.msg44119#msg44119)
Look on your B-2126 Automotive Wiring Diagram (in Owner's Manual). See .pdf file below for typical example. The area outlined in red is the "Aux Start/Isolator Panel" located under the bed platform. The
isolator is the rectangle on the right side of the red box. The
BOOST solenoid is right next to it.
Aux Start Relay is in upper left corner. Everything in the red box should be located on or near the panel in your engine bay.
See if you can locate these items on your coach.
Found on forum a new example
Trik-L-Start is not factory equipment but if you don't have one or something similar you should get one to keep your chassis batteries charged.
Keith
As you have likely learned, allowing a battery bank to get down to 11.5 VDC materially shortens battery life AND can give you a lot of "Computer errors" in engine and transmission.
So, until voltage is at least 12.2 VDC, do not waste time trying to troubleshooting electrical issues.
Ok...between a heavy work schedule and rain I finally had time to get back to my coach today. Thanks to Rudy for the phone calls and help in locating jump-start lugs that most probably don't exist.
I still can't get it to start. Even tried jumping with a connection to the first battery from my Ram 4x4.
Additional notes...
A) I've checked every connection I can reach--none are loose. I can't reach the back to batteries, and I haven't chased to the starter to check its connections.
B) With not much to lose at this point, I used jumper cables (red/red) to connect/bypass the boost solenoid. Still didn't crank.
C) After charging the batteries the dash voltage guage shows between 12 and 13. After bypassing the solenoid it showed 13.
Turning the key didn't seem to draw much if any.
When I turn the key all I get is intermittent flashing on the dash with a slight clicking sound. When this first began the engine did just barely turn--probably not a full revolution.
Please remember, the rig is about as low it as it can get--almost on the rear tires. My aux air isn't working either. I mention this before extreme crawling in the already tight areas is suggested. I can get under it (I own a business that requires some of us to spend time in tight crawlspaces,) but some spots may be out of reach.
I'm adding pictures to show what I'm seeing from the bedroom hatch.
Suggestions/help?
Thanks!
Steve
Just a thought, I had the same issue with mine , did a battery test and had a bad cel replaced the battery and bingo . Good luck
Steve,
AFAIK, the Blue Sea "battery link" and the (replacement?) battery isolator on your coach are not original factory equipment. Someone has made changes to the OEM charging setup. It appears odd to me because that Blue Sea device (which is connected to both battery banks at the BOOST solenoid) is normally utilized to serve the same basic purpose as a battery isolator. Why does your coach have both of them?
BatteryLink⢠Automatic Charging Relay - 12V/24V DC 120A - Blue Sea Systems (https://www.bluesea.com/products/7611/BatteryLink_Automatic_Charging_Relay_-_12V_24V_DC_120A)
The fact that your coach is no longer "stock" makes it harder to do remote diagnosis of your problem, because we don't know what was changed. The changes might constitute an "upgrade", but no way to know.
It sounds like you are not getting sufficient amperage at the starter to crank the engine, OR the starter solenoid is not getting the signal to "crank" from the ignition switch. This could be caused by:
1. Bad battery cables, or bad/corroded/broken cable connectors.
2. A malfunctioning Aux Start Relay. See B-2126 Wiring Diagram linked in Reply #20 in this thread.
NOTE: The Neutral Start Switch must operate correctly to give Aux Start Relay "permission" to close.
NOTE: Even with adequate battery volts/amps at the starter, if Aux Start Relay fails to close, turning ignition key to START will not crank engine.
3. Loose or broken cables or loose/corroded connections (POS and GROUND) at the starter solenoid.
4. A malfunctioning starter solenoid (located on the starter).
There is no "easy" way to figure this out. You need to pursue a logical trouble shooting process. Start at the batteries, and verify the proper operation of the starting power circuit all the way to the starter motor.
Looks like you've got the big Red Cummins ISL 9 450. This engine needs around 1000 amps to start (manual recommends min 1250 CCA).
Jumping to a running car for say 20 minutes should charge
good chassis batteries to the point where you maybe can get it started.
Without good chassis batteries that can take a charge, Walmart jumper cables and a car battery alone just won't provide the 1000 amps you need.
If you don't mind spending a few $$ (or have roadside asst) a good heavy tow truck driver with OOO high current cables and charger should be able get you started (he starts big diesels all day long), then you at least can get the coach moved and continue to work on it.
As an aside to Peter's comment about the engine...that looks like a
terrible place for all those important electrical components to be mounted. They are crammed up in very close proximity to the HOT engine block, with almost no free air space around them. A poor engineering decision IMO.
I always thought the placement of the isolator panel on
my coach was bad. Down low, right behind the rear wheels where it gets splashed with water and covered with road grime. But compared to Steve's coach, the placement in my coach looks a LOT better! At least my panel gets some cooling air, especially since I replaced the 55 gallon barrel sized OEM muffler with a small resonator. :thumbsup:
I'm guessing he's got an East, West bed arrangement. Mine looks nothing like that.
Well, finally had part of a day to resume troubleshooting...and, the coach remains dead-in-place.
Thanks Rudy and Mike for letting me bend their ears.
So many of you have provided a number of insights. It seems logical the process begins with replacing the batteries. With limited time--not enough of it to raise the coach using the reverse method with a portable air compressor--I decided to try something else. Since the current batteries will be replaced I went ahead and purchased 3 new group 31 lead acids. Since I don't have enough room to actually replace the current ones I connected the three new batteries with new cables and then connected them to the chassis batteries with a heavy-duty 2 awg jumper cable. Each battery has 1,000 cranking amps.
It didn't work. Below is a photo of how they were connected.
Interestingly, once connected, the dash voltage gauge did not rise...it was on about 12.2 before connecting, and remained there even after connecting. The connection with the jumper cable was solid on both ends. I even squeezed close enough to the opposite-end chassis battery to connect it after connecting to the other end proved null.
So--
1) was my process of connecting the new batteries flawed?
2) If not, does the voltage not increasing point to a possible problem down the line?
3) Also, I have no idea why the coach has the Blue Sea device along with another aftermarket battery isolator. The Blue Sea device would be easy to remove--should I?
It was too cold today to consider working on it (25F here...I'm a wimp!) and I'll not be able to try anything else until possibly next Sunday.
Thanks for all the input. I'll admit some of it is a bit advanced for me, but I am drilling deeper to understand the devices and terms. Hopefully nobody else ever faces the same situation as me, but, if so, at least I'll be able to help as y'all have.
Thanks!
Steve
1. Sounds OK to me, and if everything else on the coach was correct, may have worked (?).
2. Yes, there is a problem down the line. Will require further investigation.
3. No, don't remove it until you understand what it is doing. Will require further investigation.
Steve,
I hate to be a Debbie Downer, but...
With the chassis batteries at 12.2 volts, connecting the new batteries at maybe 12.5 - 12.6 volts will immediately drop the voltage to match because the dead chassis batteries will be drawing a high current trying to recharge.
Even though 2 gauge seems like a heavy jumper, unfortunately this will not give you the 1000 amps needed for cranking. A heavy tow truck uses 000 gauge for jumpers, some with extended cables use 0000 gauge jumpers.
Just interesting information for fellow nerds - here is what a heavy tow truck would have mounted. 3000 amps surge, 1000 amps continuous, 3/0 cables, 5 HP gas engine. (19 HP engine with optional air compressor).
Goodall 051538 CAP-START 3000 Vanair Super Capacitor 12V 3000 Amp Jump... (https://www.jbtools.com/goodall-051538-cap-start-3000-vanair-super-capacitor-12v-3000-amp-jump-starter/)