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Old 11-21-2018, 10:33 PM   #1
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Join Date: Oct 2017
Location: E Central Tejas
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Year: 1998
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Chassis: IH 3800, 8 window
Engine: T444E w/ Spicer 5-speed MT
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All RV'ed Up With No Way To Go (apologies to Jim Steinman and Meat Loaf)

Howdy all y'all, its been a while. Happy Turkey Day! Seems a propos, given how much of a turkey I'm feeling 'bout now. I've rooted around here considerable before asking for help, but I found nothing that resolved the problem.

Yup, friends and neighbors, yet another bus electrical issue...

Pulled into my latest campground, shut her down, and commenced to pitching camp. Didn't get too far along with the settling in process before I was told to relocate to a different slot, but not before discovering the headlights were on. Which was kinda odd, since I didn't use the headlights that day.

This second time I feathered the engine and pulled the key, a buzzer sounded. Leaving it switched to accessory to shut it up, I confirmed the headlights were still lit, so I took the path of least resistance (pun fully intended) and disconnected the batteries.

Days later, I decided to fire up the engine and try to locate the gremlin's lair. Yay skippee; no start, no instrument tell tales, no lights, no (thankfully, I suppose) buzzer.

Nothing, nada, bupkes, zilch.

After confirming both batteries were at full charge, I checked the inline fuse holders in the battery compartment and dashboard fuse block without finding any blown. I traced the leads from the lead-acid to the starter without finding a kill switch.

(Not to backslide, but is there any trick to getting the batteries' sliding tray to slide? I hosed out all of the grot and grunge it'd accumulated, but it still hangs on the backside slide.)

While it wouldn't likely account for the headlights, I thought maybe the buzzer buzzing on the key's removal might've been due to to either of the escape window's or the roof hatch's switches not being entirely closed. Still looking to test that hypothesis.

Is this something any of you folx have experienced in your considerably greater Skoolie tenure?

Surely hope one of y'all can point me in the right direction before I go bald from this head-scratcher of a problem.

Thanx!!!
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Old 11-22-2018, 02:14 AM   #2
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Buzzers sounding my imply an interlock that has been tripped which would be a neutral safety switch preventing you from starting. But if that were the case, as soon as the batteries are powered up the buzzers should start buzzing again.

Before we can start diagnosing the problem we need to know what chassis is under your bus, who made the chassis and body, which engine and transmission, and the model year of your bus. It is all important as each of those variables will change the locations of important stuff.

You mentioned you could not find anything preventing the juice to flow from the batteries to your starter. But did you make sure you have a good, clean, and solid ground from the batteries to the frame and body? Without a good ground nothing will work correctly.

Do you have juice at the starter? I have been fooled more than once by battery cables that look perfectly find on the outside only to discover that they were nothing but solid green on the inside which lets very little juice through.

In your quest to discover where the juice is getting lost you will find a test light to be your quickest diagnostic tool.
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Old 11-22-2018, 07:42 AM   #3
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Check your interlock, check your body solenoids.
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Old 11-22-2018, 09:59 AM   #4
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I would be testing the headlight switch for power. No way those lights should be on when in the off position, ever.


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Old 11-22-2018, 08:57 PM   #5
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Join Date: Oct 2017
Location: E Central Tejas
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Year: 1998
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Chassis: IH 3800, 8 window
Engine: T444E w/ Spicer 5-speed MT
Rated Cap: I prefer broad-brims hats
Quote:
Originally Posted by cowlitzcoach View Post
Buzzers sounding my imply an interlock that has been tripped which would be a neutral safety switch preventing you from starting. But if that were the case, as soon as the batteries are powered up the buzzers should start buzzing again.

Before we can start diagnosing the problem we need to know what chassis is under your bus, who made the chassis and body, which engine and transmission, and the model year of your bus. It is all important as each of those variables will change the locations of important stuff.

You mentioned you could not find anything preventing the juice to flow from the batteries to your starter. But did you make sure you have a good, clean, and solid ground from the batteries to the frame and body? Without a good ground nothing will work correctly.

Do you have juice at the starter? I have been fooled more than once by battery cables that look perfectly find on the outside only to discover that they were nothing but solid green on the inside which lets very little juice through.

In your quest to discover where the juice is getting lost you will find a test light to be your quickest diagnostic tool.
Whoops, my bad- cerebral flatus. Forgot that the mobile version doesn't display the user's specs. Here they be:

1998 IH/Navistar 3800, with a 175 hp T444E and a Spicer 5-speed MT, in a 30' long, 8 window Thomas.

The ground connection to the frame was tight, and doesn't look corroded, but I got no reading with my VOM at the starter.

It seems it must be something more catastrophic than corrosion, because this happened all of a sudden: without any operational problems before finding the head lights were on, and then the buzzer, which prompted my disconnecting the batteries.

How might I confirm, unlikely tho it seems, that I didn't reconnect the batteries correctly?
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Old 11-22-2018, 09:01 PM   #6
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Quote:
Originally Posted by EastCoastCB View Post
Check your interlock, check your body solenoids.
Yanno, I spent most of the day trying to indentify and localize interlocks and body solenoids on my POS cell phone, with no joy.

I think I'm camped in am EM black hole.

First the bus' gremlins, then the battery on my toad suddenly went DOA, my fridge has just crapped out, my battery charger crapped the bed, and my cell stutters and glitches badly, randomly skipping back and losing pages.

I wonder if that sextet of 11 kV high tension distribution wires 40 yards from my site are responsible...
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Old 11-22-2018, 09:06 PM   #7
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Originally Posted by BlackJohn View Post
I would be testing the headlight switch for power. No way those lights should be on when in the off position, ever.


John
Good idea. Once I have juice back to the dashboard, I'll give it a go. Would I be guessing correctly there should be no continuity between contacts when it's switched off?

I'm an OK shadetree mechanic, but when it comes to electricity, I could screw up an anvil with a rubber mallet!
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Old 11-22-2018, 09:35 PM   #8
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Join Date: Jun 2013
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Chassis: GMC
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Quote:
Originally Posted by haz.matt.1960 View Post
Good idea. Once I have juice back to the dashboard, I'll give it a go. Would I be guessing correctly there should be no continuity between contacts when it's switched off?

I'm an OK shadetree mechanic, but when it comes to electricity, I could screw up an anvil with a rubber mallet!

You should have juice there regardless if the dashboard has any. The 12v is a direct takeoff from the batteries at a terminal block or post for 12V+
That will show as power on one place on the switch, tested to ground.
There are other positions that become active as you pull the switch on. Dash lights maybe but might be separate too. And most have a built-in dimmer or rheostat.
The only time you see full continuity is when switch is fully out giving low beams and or on high beams. Disconnect batteries before a continuity check. Connect back for power to ground checks.
Learn all you can to save on repair bi$$s,



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Old 11-24-2018, 03:51 AM   #9
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If your batteries are charged up if you had connected the terminals backwards you would have discovered that as soon as you touched the second cable to the battery.

I know this is going to sound elementary but you need to start at the beginning--at the battery. If your battery(s) are fully charged your test light will light up.

When the battery cables are connected you should have a hot lead going to the starter--it only engages when the solenoid is tripped by turning the key to the start position. Depending upon how it has been wired there might be a master breaker right by the battery. If it trips you won't have juice anywhere. Again, it all depends upon how it is wired but the hot lead going to the starter may have a second wire leaving the starter going to the chassis and/or to the body. I have also seen it with a second wire coming off of the battery going to the body. On a Thomas bus that second wire will go to a solenoid operated by the key switch to power up the switch panel.

Most Thomas buses had a solenoid that powered up the switch panel--none of the switches will work unless the key is in the run or accessory position. The solenoid will have a hot lead on one side. If that solenoid has gone bad you will have no power on the switch panel but you should still have power to the IHC part of the dash--headlights, key switch, etc.

Using a VOM will work but it is a lot harder than using a test light. Hook the end with a clamp to a good ground and start hunting for juice. When you find it the light will turn on. It is much easier than trying to find continuity.

If you have not juice at the starter then there is a break in the circuit between the battery and the starter. It is usually due to a bad ground--either on the cable attached to the battery or attached to the frame. On one Thomas everything looked great until we started trying to move stuff. The ground cable to the frame was barely finger tight. Because it had been loose for sometime it had developed some corrosion to the point where it was no longer making contact. Finding that loose connection drove me nuts! The bus had just over 10K miles and it wasn't starting. GRRRRRRR!
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