dim headlights 1978 MCI converted to 4 headlight system

farmallrick · August 17, 2013, 07:48:46 PM

Hi New member Easley SC Just bought a 1978 MCI that has been converted by a gentleman from Mississippi He did a great job in my opinion. We have really enjoyed the coach so far. I have been doing some gen. maint. lights etc. I feel the headlights are dim, it has been converted to a 4 rectangle headlight system. I have installed all new headlights ( blue light) that seemed to help some, any ideas? Coach runs great (8V71) about 22k on overhaul according to paperwork. Allison Auto Trans seems to shift fine min. leaks on engine and trans. uses about 1 gal SAE #40 wt about every 1000 miles witch is par for this engine I believe. Now working on getting dash lights to work side dash/switch lights working fine. Only the headlights seem dim more so on high beam setting any ideas. I have replaced the main Batteries with new ones like the coach called for. Thanks Rick Sundblad Easley SC

wildbob24 · August 17, 2013, 10:16:01 PM

Rick,

Welcome aboard.

In my experience, dim headlights can usually be traced to bad grounds. Another possible culprit would be the floor mounted dimmer switch.

Keep an eye out in the calendar section here. Periodically, some local busnuts hold rallys at Palmetto Cove campground, near Cleveland SC. Very close to you. I would be a good place to meet some like minded folks.

Bob

chessie4905 · August 18, 2013, 04:12:46 AM

I've found the blue light didn't illuminate as well as regular. Take a voltmeter and check the voltage at the headlamp plugs. If it is ok, the Sylvania Silverstar, or Silverstar ultras are quite good. The ultras have a shorter lifespan than the other, which is shorter than a regular headlamp. They also cost more than regular lamps. Of course, these are 12 volt models.
I don't know how they will hold up from road shock in a coach though.

gumpy · August 18, 2013, 06:06:41 AM

First, I would verify that the headlight sockets are hooked up properly. It's easy to get the wires connected wrong.

It's possible the 78 might have come from the factory with 12 volt bulbs, in which case they would be wired in series with a center tap to 12 volts. I think they started this wiring
in the late 78 models. If that's the case, then it might be that the previous owner changed the power feed to 12 volts, which will result in only 6 volts to each headlight
and therefore a very weak output. Although I really doubt this is the case, you definitely should test the voltage at each headlight.

Then, if the voltage is correct, then check grounds and wire and connections for corrosion. Also, make sure the wires are properly sized for 12v bulbs.

TedCalvert · August 18, 2013, 06:19:27 AM

Be sure to check the voltage with the bulbs connected.

farmallrick · October 14, 2013, 05:56:27 PM

Sorry it took me so long to get back been busy Thanks for the help Im betting on the dimmer switch I about have to stand on it to get it to from bright to dim etc. and i weight a good 250 LOL Also checking ground and voltage this weekend when I get back to the project. Inside the coach it has a tag that says headlights are a 12 volt system so I think you are correct on that part!! I feel a bad ground/ dimmer switch may be the gremlin!! Thanks Again Rick Sundblad I'll keep an eye out for the deal in Cleveland SC !!!

gumpy · October 14, 2013, 08:06:42 PM

Quote from: farmallrick on October 14, 2013, 05:56:27 PM
Sorry it took me so long to get back been busy Thanks for the help Im betting on the dimmer switch I about have to stand on it to get it to from bright to dim etc. and i weight a good 250 LOL Also checking ground and voltage this weekend when I get back to the project. Inside the coach it has a tag that says headlights are a 12 volt system so I think you are correct on that part!! I feel a bad ground/ dimmer switch may be the gremlin!! Thanks Again Rick Sundblad I'll keep an eye out for the deal in Cleveland SC !!!

Yeah, probably not the dimmer switch. In a properly wired 12v system, the dimmer switch only controls a relay coil. Could be relay contacts, but most likely either improperly wired sockets or bad grounds.

bevans6 · October 15, 2013, 03:58:36 AM

Just a possibility - my similar vintage MCI has a Universal Coach Parts (Universal Coach Parts was owned by MCI and is now called MCI Service Parts) conversion kit installed that was an MCI-sold solution for 12V headlights. My 1980 MC-5C came factory with 24V headlamps. The conversion is a black box maybe 4" by 6" by 1" deep that converters 24V to 12V, one for each side, and the lamps are pretty dim. I went to Hella halogen lamps without much improvement, but I haven't investigated further yet.

Brian

gumpy · October 15, 2013, 05:26:48 AM

1978 was the year MCI started installing 12v headlights. Near the end of the year. Depending on the serial number, his bus could have factory 12v headlight,
or it could have been converted. MCI issued a bulletin on converting from 24v to 12v.

The sockets on the rectangular bulbs are not wired the same as the round bulbs, and it's not obvious, so it's possible that whoever did the conversion
to rectangular simply wired them up like the round bulbs. It seems to me that when I did that on a friend's bus, because I didn't know better and didn't
have directions with the rectangular bulbs, they were pretty dim.

Bill B /bus · October 15, 2013, 10:18:59 AM

If you have 12V lights then connect via a 24 coil relay to the 12V system supply. Wire that through the old style dimmer switch, no relays just switch for hi/lo, then to the headlight wiring. Simple, cost effective solution. Gits rid of balance line and two relays.
Works successfully on two MCI's, an 85 and 86.

Bill

bevans6 · October 15, 2013, 11:36:38 AM

I was going to do that, but the OEM 12V system supply on my 1980 bus is fused at 30 amps. I didn't think that was enough to run headlights reliably but it probably is just fine if you stay away from the high wattage lights. I may try it from my Vanner now that I have reconfigured and would have up to 60 amps at 12v available.

Brian

Nineforever · October 15, 2013, 06:09:02 PM

I went with speaker LED excellent lights there available in the round 4 head light system or the retengular 4 head light set up .. excellent in this north country with all the wildlife on the roads .
The LED are exspensive but well worth the money .. there is some knock offs on the market much cheaper but not near the quality . The LED use far less power to run .
Dave

gumpy · October 15, 2013, 07:22:54 PM

Quote from: Bill B /bus on October 15, 2013, 10:18:59 AM
If you have 12V lights then connect via a 24 coil relay to the 12V system supply. Wire that through the old style dimmer switch, no relays just switch for hi/lo, then to the headlight wiring. Simple, cost effective solution. Gits rid of balance line and two relays.
Works successfully on two MCI's, an 85 and 86.

Bill

That's a great way to ruin two very expensive batteries.

farmallrick · October 15, 2013, 08:11:28 PM

OK Grumpy from minn How do you properly wire up the sockets for rec. headlights I'm sure this guy just wired them the same I would have HELP thanks Rick Sundblad Easley SC

RJ · October 15, 2013, 10:30:19 PM

Rick -

If you do a search for "MCI Headlight schematic" on this site, over on BNO (busnut.com), or Google, you should come up with the proper wiring diagram for running 12v headlamps on your 24v system coach.

When you study it, it looks weird and "that'll never work," but it does, and does reliably.

Another reason your headlights are dim is simply because they're the rectangular style. It's been shown in various places that the light output from rectangulars is inferior to round lamps, simply because of optical physics. Oh, sure, they may "look nice" and more "modern," but when it comes to safety, they're worse. IMHO, you'd be better off pulling the current lights and going back to the OEM round units and wiring them properly.

If you are going to be doing a lot of night driving, the very BEST headlamp set-up is European-code Cibie halogens, as opposed to the poor output US DOT lights. E-codes have a very sharp cut-off to the left to prevent glare to on-coming traffic, with a corresponding increase down the RH side of the road. Stock E-codes will illuminate a stop sign on a rural road at night nearly 1/2 mile away, and over a mile away on high beam. Not cheap - about $300 for a four-headlamp installation, but what price SAFETY??

Finally, since you're a newbie here, welcome aboard! Please take a couple minutes to edit your profile to include a signature line, similar to mine below, that will automatically show up with each of your posts. Simply click on the "Profile" tab above, then, in the LH menu, click on "Forum Profile Info" and follow the prompts. By doing so, we'll be better able to help direct you to parts & service sources in your neighborhood, and as a bonus, you might just discover that there's another busnut nearby!

FWIW & HTH. . .