My 1994 U300SE has a Detroit 6V92. Yesterday in traffic I noticed that voltage went to zero momentarily as I activated the turn signal. Later the engine cut out momentarily when I was turning off the freeway, also signaling. Safe at a Wal-Mart, I determined that using the turn signal, windshield wipers, or dash H/AC cut the voltage and killed the engine. Other accessories seem to be OK, including emergency flashers. Of course, this happened on Friday afternoon, and there was no support from Foretravel or Motor Homes of Texas - and local DD and GMC service facilities were closing for the weekend. I've pulled the fuses of the offending circuits and plan to get to a place where I can snuggle in and figure it out - we near Columbia, SC. Any input or suggestions?
Looking at the age of your coach, and the misc loss of power to dash things you might just have the simple problem of the ignition solenoid failing.
Under the lift up dash, centered in front of the speedo, is the large 2" round metal item with all the red wires coming in and going out, controlled by the two small wires to your key. It is a heavy duty 200 amp constant duty unit. There are a number of threads covering it's function and failure both recently and over the last 3 years on the forum.
My 93 failed, slowly doing weird things, as different electrical items would stop working. In my case, I would loose the tack, or the heater blower, or the HWH jacks would not work, or it would fail to start. It is a five minute replacement with the batteries disconnected and the auto part store part.
Someones just failed, and the one in the coach was only a 85 amp, intermittent unit, not the 200 amp heavy duty constant unit.
THANK YOU, Dave - I'll take a look. We're parked across the street from Advance Auto Parts, so maybe there's hope. I'll post later.
Oh, there is hope. You are parked, safe, warm with food and water. Across the street from a parts store, you do live a charmed life of a Foretravel owner!
Hard to check things when they work. But when my coach did not start, a volt meter on the output side red wires showed "no voltage". Intermittent problems as you go down the road, not so easy to find.
Most counter people need a year and model to look up in the computer. Try a 1994 truck and read the specs on the unit.
The one in the coaches are Cole Hersee. I got a # 24213, that replaced my old one #24143. My notes show $54. Brett Wofle suggests a much better Bluesea 9012, 250 amp, and maybe $160. A search in Tech will get the correct number.
Solenoid could be going out but check your grounds up front. Good source of ground are the two bolts that hold the steering column in place. About 4 inches from the solenoid. You can use it to check if the other grounds are good. Also check to see if all solenoid connections are tight including the wire that grounds the solenoid. If you have two big lugs and two small lugs on your solenoid, one of the small ones is the ground. Some older models only have one small terminal so the body has a ground wire to it. A test light can be a big help in finding the fault. Naturally, start with the terminals on the engine battery. Would pull and clean them as a start. Check connections at the isolator also. No need to spend big $$ for the electronic solenoid if you are not sure what the problem is. The latest Cole-Hersee will last for years. Ours does not look as if it has ever been replaced.
Pierce
Just to verify - is this the ignition solenoid in question?
Yes.
One large lug will always have chassis battery voltage-- hopefully 12+ VDC and with engine going 13+ VDC.
The other large lug will have that same voltage only with the key on.
Short term work around if it fails and you are on the road. CAREFULLY MARK all wire on one large lug and move them to join the wires on the other large lug. Be sure to put them back in their original position when you arrive and want the ignition off.
Brett
Thank you, Pierce. I'm checking grounds with a multimeter.
Okay, with switch off, one side (right, red wires) shows continuity and the left side shows about 8 oms. Switch on, the left side shows -0.25 ohms. Any significance to this?
Larry,
Check voltage between each large lug and the front ground "gang" connection or other good ground.
My long term solution here, works great so far.
Dash solenoid removal (http://www.foreforums.com/index.php?topic=19024.msg132561#msg132561)
Good luck,
Rick
My 1991 6V92TA with DDEC used to quit every now and then and the voltmeter would go under 10 volts or sometimes all the way to 0 when it quit. After a while I discovered one of the clamps around the terminal on the cranking battery had a hairline crack that was just barely noticeable. I replaced the clamp a year ago and drove my coach all over the country without any engine failures since then so I'm pretty sure that was the problem.
Brett, thank you. 14.4 on the left side and 13.2 v on the right, both with the motor running.
On a high voltage AC relay you want less than 1 volt difference between the two sides of the relay or the relay is bad. This is a low voltage DC relay you're dealing with, but I presume it's bad if you're losing that much voltage across it. The relay is probably hot to the touch with that amount of resistance in it.
Larry,
That loss of a volt, while acceptable in terms of adequate voltage to "ignition hot" circuits means you are turning a lot of electricity into HEAT in the solenoid. Probably because the contactor surface is pitted.
So, that voltage will not give you any of the symptoms you are experiencing, but certainly suggests that the solenoid is a candidate for replacement.
If your symptoms are intermittent, I would hook up a wire from the ignition hot side/lower voltage side, and one from a ground source. Go for a drive, work turn signals or whatever caused the failure with a voltmeter hooked up and see if voltage drops below 12 VDC. If so, repeat on the battery side of the solenoid, because a loose connection between battery and battery side of the solenoid could cause the same symptoms.
Brett
...is the relay making a chattering or buzzing sound?
Eliminate the solenoid from the circuit and see if the problem goes away. Get the heaviest gauge wire they have at the auto parts store and make a little jumper cable across the solenoid, then go for a drive and use your turn signals and everything else you normally use while driving. Just go around the parking lot first and when you get braver go out on the road. If the jumper solves the problem replace the solenoid... or just replace the solenoid cuz it's gonna be bad for sure if it's losing that much voltage... I'll test mine and see what it has for voltages if you want to compare. I just drove my coach yesterday so I know the solenoid is good.
Scott's jumper suggestion will work, but be VERY careful, as either end of the jumper touching ground could cause extreme heat/fire. It would also produce sparks that would not be good for electronic components like the Allison ECM.
You could achieve the same thing by marking the wires on one large lug and temporarily moving them to the other large lug, AND nothing to buy.
I think that the solenoid is still a primary suspect for the problem. With a 1.2vdc drop across the contacts with no other current draws, the drop would probably be even worse when another device is activated (like turn signals, etc.).
RRadio's advice to temporarily bypass the solenoid to see if the problem goes away seems to me to be a good first cut at the problem. :)
Craig
Unfortunately a beautiful theory may have just been destroyed by an ugly fact. I just tested my solenoid and found way more than 1 volt drop across it. My solenoid works for sure because I just drove my coach last night with all the lights and heater blower motor running. My solenoid isn't hot or making any noise... so I dunno... when my DDEC was quitting and my voltmeter dropped it was due to a cracked clamp on the post of the cranking battery ...same exact symptoms
Okay, I've bridged the terminals on the solenoid, started the engine, replaced the fuses, and - everything WORKS in every combination. Quick question, though. How do you shut the engine off when the key doesn't have any effect? Do I have to unbridge the solenoid?
Years ago I installed a master electrical shutoff switch at the engine battery ground. I expected to be able to shut everything down by switching it to off. Didn't work.
So I pulled the jumper bridging the terminals and all is quiet again. Now to find the right part...
Cole-Hersee 24213 See at: Battery-Related Products | Battery Selector/Master Disconnect Switches24213 | (http://www.colehersee.com/home/item/cat/210/24213/) Other numbers are obsolete. $35-$55 at parts stores. Ground to either small terminal, +12V from ignition switch to other.
Solid state is great but just costs more.
Pierce
THANK YOU one and all for your help. I don't know what I would have done left to my own limited knowledge. Each comment and suggestion was valuable, and very much appreciated. We're good to stay another night here at the Wal-Mart Supercenter in Newberry, NC - their hospitality for two consecutive nights was gladly granted. Tomorrow, we head to our destination, where I'll park, turn off the key, retreat to the back bay to turn off the master switch, return to the cab, open the dashboard, and separate the quick-disconnect I installed on the jumper wire. Then I'll have a few days to find the correct replacement solenoid. I'm feeling pretty confident, and VERY grateful. Thank you all.
Larry,
Sure you will do it but all of us should not forget to disconnect the engine battery (or house, depending) before changing out any solenoids.
The owner of the largest FBO at our airport was working on the back seat of a big twin when he shorted something. Tried to put it out but failing, tried to get out, stumbled and hit his head on the concrete floor. The twin burned up taking Leo, the hanger, along with two other big twins. I had lunch with him a couple of days before. How quickly things can happen.
Pierce
After you replace the solenoid, you might take the old one apart and file the contacts. Ten minute job and you'll have a spare jic.
Chuck
...but don't use an emery board (sandpaper) fingernail file because it'll form a glass like silica coating on the contacts when they heat up ...at least it does on high voltage AC relays almost every time, so I use a tiny breaker point file made for engine ignition systems.
Still fighting this project. I've installed a new Cole-Hersee solenoid, and now I get nothing when I turn the key on. There's juice to the battery side, all the wires are accounted for, and I suspect the ignition switch - which had been a little finicky in recent months. If I could get the plug off the back of the sucker I could test continuity, but there are a couple of tabs that thrwart removal of the plug. Any suggestions?
Yes. Go to the small terminal on the ignition solenoid. When you turn on the key, you should see 12 VDC at the small terminal. If you have two small terminals, one is ground, the other the one from the ignition switch (If only one small terminal, the solenoid grounds through the body of the solenoid.
Check it two ways-- see if there is 12 VDC from the ignition switch. Take a small jumper wire from battery side large lug to the positive small signal terminal (with the wire from ignition switch removed).
Thank you, Brett - I did get 12v at either small terminal with the key on. I have both the red and blue wires on a single small terminal of the solenoid, but both terminals seem to work the same. I didn't run the second check yet, as I am a little uncertain of the process.
Not sure I understand. If the small signal terminal has 12 VDC, the other large lug should also have 12 VDC and all "ignition on" things should work.
That's what I'd have thought too. But... battery side hot, both small lugs hot with switch on, and large lug with red wires no voltage at all.
Make sure the solenoid is grounded. Some ground through the body (so if not mounted on chassis metal, you will run a small wire from the bolt holding down the solenoid to the ground terminal panel). If two small terminal, one should go to ground, the other to ignition.
Brett
I'm getting .07 ohms from the body of the solenoid to ground, so that seems to be OK. Both small lugs show 12vdc only when the ignition is on - I don't think either one is a ground, and the solenoid appears to be designed to ground through the body.
Okay, it's beginning to dawn on me, but let me run it by you first. The second small terminal - which shows 12vdc with the ignition switch ON - should be grounded? If so I could run a wire from the terminal to ground and everything should be OK?
Larry,
If you have the Cole-Hersee 24213, Brett has it exactly correct. Ground either one of the small terminals and connect the other to the wire to +12V from the ignition switch when you turn the key on. Can't go wrong here.
Reading your last post, yes, bring a ground wire up to the empty small terminal.
Pierce
Ahhh... that sound you hear is an old Detroit Diesel turning over just like it's supposed to. Oh, and me, breathing a huge sigh of relief and gratitude. Wife Carol asked - how do your Forum friends get back to you so quickly? I'm asking the same thing, and once again I'm indebted to you who know your stuff so well. Kudos especially to Brett, and thanks to all.