Headlights go out and then later come back on

Brett G · May 26, 2014, 06:20:50 PM

Hi everyone, I'm looking for some feedback on an issue I'm seeing with my Head Lights recently. As I'm driving down the road the head lights just shut off. I was lucky to then turn on the fog lights. Hitting the dimmer switch several times didn't do any good. Nothing. After about 5 minutes, the head lights then just came back on. This then happened again for the 2nd time with the lights coming back on after 10 minutes later. Would it make sense to start with the dimmer switch or do you think I've got other issues? Thanks in advance.

Brett

1970 MC7

georgemci102a2 · May 26, 2014, 06:41:57 PM

I remember having the same problem in the past and it turned out to be the dimmer switch,but the headlights would work if i held the switch down.

...George.

eagle19952 · May 26, 2014, 06:42:22 PM

when they do that a resettable breaker is cooling off enough to remake contact.
you probably have a short.

luvrbus · May 26, 2014, 07:44:57 PM

I would replace the dimmer, relay and circuit breaker and be done with it is not all that expensive and a easy job to do

Brett G · May 27, 2014, 05:28:49 AM

Thank you all

gumpy · May 27, 2014, 05:40:09 AM

You're overloading the circuit breaker.

This is not unusual if your lights were rewired from the factory 24v to 12v and they didn't change the circuit to handle the additional current.
Same thing happened in my MC9 on a dark deer infested highway in Wyoming.

It could also be a short, but most likely just a weak circuit breaker from the constant overload of 12v bulbs.

Mex-Busnut · May 27, 2014, 05:49:39 AM

Quote from: gumpy on May 27, 2014, 05:40:09 AM
You're overloading the circuit breaker.

This is not unusual if your lights were rewired from the factory 24v to 12v and they didn't change the circuit to handle the additional current.
Same thing happened in my MC9 on a dark deer infested highway in Wyoming.

It could also be a short, but most likely just a weak circuit breaker from the constant overload of 12v bulbs.

Exactly. Volts X Amps = Watts. You half the voltage from 24 to 12, you need twice the amps to produce the same wattage for your driving lights.

Brett G · May 27, 2014, 07:35:22 AM

Everything that I can see tells me it was not rewired. Looks like the original wiring.

edvanland · May 27, 2014, 12:29:02 PM

I kept having problems with my headlights on my MCI 7 which had been changed to 12 volts. Got fed up and ran a 10 ga wire from the house battery to the head light area then rewired everything to 12 volts. Now I have a switch on the side panel that is either low off or high. The original high beam indicator now tells me the lights or on low. The rest room light, which I don't know what it was for, now tells me when they are on high. That red light indicator is bright. I love the way they work now and mainly I don't have them go out at the worst possible time. My 2 cents worth.
ED

Brett G · May 27, 2014, 12:34:16 PM

Thanks Ed

gumpy · May 27, 2014, 05:53:24 PM

do you have 12v bulbs or 24v bulbs? If I'm not mistaken, your bus came with 24v bulbs. If someone changed to 12v bulbs and just changed the feed to 12v, then the circuit breaker
is overloaded, especially on high beams.

Don't cobble it. Figure out the reason and fix the problem correctly. Headlights are kind of important.

Brett G · May 27, 2014, 06:41:42 PM

I'll get into it and report back as I'm not sure. Thanks

Brett G · May 28, 2014, 04:33:29 PM

Ok Guys, I tested tonight with my multimeter and found that I do have 24 volts going to the headlights. Could it be the headlights themselves? It looks like they are 28 volt headlights if that makes sense. One is the Wagner 28v 4579 80/60W and the other is a Wagner 28v 4813 90W Thanks in advance

Some pictures - https://plus.google.com/photos/110667739701584973079/albums/6018631037600085809?authkey=CMDi1e7CgZuZOQ

gumpy · May 28, 2014, 04:53:39 PM

It sounds like your bus was not modified to 12v. That's good news, and bad news. Good news in that the wiring probably has not been bastardized too badly. Bad news in that 28v headlights
are getting harder to locate, and even more bad news in that it means you probably have a short in your wiring somewhere which is tripping the circuit breaker. It's probably not the headlights.
It's probably the wiring. Maybe a wire has rubbed on the frame till it's rubbed through the insulation.

I don't have a diagram for the MC7 wiring. Maybe if you have one you can scan it and post it here and I can look it over. Maybe someone else will have one and can post it.
I'm not familiar with the headlight circuit on the 7.

Brett G · May 29, 2014, 07:07:09 PM

Thanks for the reply Gumpy. I've added the electrical diagram and a page that says the bus originally came with 50 watt headlights. You don't think it's an issues have the higher watt bulbs? Thanks

https://plus.google.com/photos/110667739701584973079/albums/6018631037600085809?authkey=CMDi1e7CgZuZOQ