Weird Headlight Situation

[RJ]

At the end of our 18th day on the road, I noticed something weird with my '78 MC-5C's headlights: The low beams wouldn't turn off when they weren't even turned on!  I had to kill the main electrical disconnect to get them to go out, leaving me without the house batteries tonight.  (Fortunately, we're plugged into 50amp service, so nice & snug!)

More info to work with:  The main headlamp switch was turned OFF.  It was never turned on today except for my pre-trip this morning, after which it was turned off for the rest of the day.  We arrived at our evening stop two hours prior to sunset, so didn't have to drive today with the headlights on.

In addition, the PO wired in a flasher switch allowing one to flash the headlights to truckers to signal it's safe to pull back in after passing my rig.  I've seen the modification on the electrical schematic for the coach, and it appears to have been wired correctly.  However, I suspect that this may have something to do with the issue, since I've been using the flasher a LOT over the last couple of days.

I'm not going to stress over this for the next couple of days, until I reach my son's in Colorado Springs on Tuesday (where we'll be for a week), thus giving me time to attempt to sort out the issue.

But if any of my fellow busnuts (especially MCI owners) have ideas and/or suggestions for solving this puzzle, I'm listening!

TIA,

RJ

[stanton]

I will be the 1st one to say it, bad grounds create the most unusual problems.
That and of course check the switch, it may be fried .

[luvrbus]

No way a MCI with a headlight problem  ,probably a relay fried closed or a hidden daytime running light switch 

[gumpy]

I'm not aware of an MCI designed modification for a "flasher" switch, so I assume it was PO designed. Did he use a relay in the circuit, or did he wire it direct to the low beam feed? Also, did he connect it to the high beams, or the low beams.

If it's relay based, that's where I would start. If it's direct, then I would check the diodes in the headlight circuit.

Next question, when the low beams are on without the headlight switch being on, what happens when you hit the dimmer switch? Do the high beams come on? Do the low beams stay on?
Does it have any effect at all?

[Dave5Cs]

RJ bypass the flasher switch and see if that works. If it does leave that out and just flash your lights off then on manually to trucks going by. Thats what i do. Then when you get to where you can work on it replace the flasher switch or not.
Dave5Cs

[boxcarOkie]

When in doubt, always take the By-pass ...  Having no earthly idea as to why this headlight thing is not working I will dive in here.  I will add my two cents.

I no longer clear trucks, in the daylight hours, they are supposed to know where it is that they are (lane-wise).  Another reason I do not clear them is they do not clear me, they never thank you any more when you extend the courtesy to them.

There is a rumor going around that the D.O.T. established a ruling that they are prohibited from this practice now.  This rumor has not been confirmed, but I did notice they are not clearing each other.

Thread drift?  What thread drift?  Did you go out west of town to the bridge RJ?

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[RJ]

An update:

This morning I opened up the electrical panel and removed the "momentary on" flasher switch and disconnected it's wiring.

Turned on the power - headlights were off.  Yeah!

Turned on the headlight switch - no lights.  Oops, forgot to turn on the ignition key first, still sleepy, I guess.

Turned on the ignition switch, turned on the headlight switch and I have one headlight only.  Hmmmm. . .

Time to roll for the day, decided to sleuth further upon the end of the day's run.

Settled in after 250 miles, dug into my stash of lights and pulled out another hi/lo headlight.

Installed new one on side that was not working this morning and bingo!  I now have two working headlamps again, plus all four high beams.

Further analysis as to hiccup's cause is needed, but suspect momentary on switch failed internally.

Having that switch is a nice little feature, but, as was pointed out in a fellow busnut's post, the lack of courtesy in acknowledging "clear" flash to 18-wheeler jockeys makes me think the hole would be better used for the fog lamps I'm going to be installing at the end of this tour.

Thanks to all my fellow busnuts for your suggestions, they're all appreciated.

FWIW & HTH. . .

[lostagain]

Glad you figured out your electrical problem RJ.

I think flashing "clear" to signal a passing vehicle it is safe to pull back in front of you is not necessary on the freeway. That is why lots of truckers don't do it anymore. It is useful however, on a 2 lane, when there is oncoming traffic, to let the passing truck know he can cut back in front of you.

Now a days, there are so many trucks on the highways, there is not much waving or flashing of lights anymore. It is "dog eat dog" out there, everybody is in it for themselves now...

JC

[lostagain]

When I was driving truck last year, at night, I found that some truckers flash head lights and clearance lights. Most don't though. The main benefit is that it keeps you alert and awake. The Freightliner I was driving had a button on the steering wheel to momentarily interrupt the clearance lights. That feature is on by popular demand from customers. I think most late model tractors have that too. But not everybody uses it. Depends what kind of mood you are in that night: you want to keep to yourself and don't flash, or you feel all friendly and exuberant and flash every truck you meet...

JC 

[boxcarOkie]

Being the curious type, I have been doing some research on this.  My trucker friends tell me that it is not a ruling by D.O.T. and it is just a lack of courtesy on the part of this "new breed of drivers."

They tell me that 8 out of 10 trucks hauling garbage (produce haulers) out of
CA are being driven by foreigners and that they are somewhat under-educated in the ways of the American Trucker.  That it has been going on for about ten years.  It makes sense to me, latest data I could find says that the largest concentration of Islamic folk in the country is now L.A..

Not long ago, in Ill. they caught out of county non-U.S. Citizens taking the CDL test for their buddies. This was being routinely done, a guy would go in and take the test, pass, then give the data card to another guy (some who could not speak English) and he would go get the CDL.

I see a lot of turban wearing drivers, various foreign flags painted on the back of trailers, and have personally stood next to these goat loving, bad smelling drivers at the fuel desk at the Flyin J or the TA.  It is as they have not backed up to a bar of soap in weeks.  Late at night they like to play their brand of music on the C.B. and believe me, it isn't Merle or Johnny Cash.

This last trip I saw them everywhere, taking their fair share out of the middle of the road, riding my butt, and generally speaking, doing a lousy job of it.

I am not clearing them, I am staying clear "of them" ... period.

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[Boomer]

Right on, Don!  Up here there are hoards of them running south out of BC, speeding, third lane violating, tailgating.  Far cry from when I drove.

[luvrbus]

LOL you guys ever take time to see what is behind the steering wheel on these tour buses now a days it's frightening to say the least one here wiped out 1/2 of a McDonald's in 1 pass