Reply
 
Thread Tools Display Modes
 
Old 03-23-2011, 07:07 PM   #1
Mini-Skoolie
 
Join Date: Feb 2011
Location: Backwoods of Pennsylvania
Posts: 34
Year: 1999
Coachwork: Thomas
Chassis: International
Engine: T444
Rated Cap: 22
Need help with the high beams

I was driving the bus to work out of town the other night and I turned the headlights from high beam to low beam. All was fine until I switched back to high beam and I got nothing but darkness, back down to low beam and everything was fine. Now the troubleshooting begins, the dash indicator says when the light is on high beam or low beam so the switch is operating normally. I unplugged the front light wiring harness from the main wiring harness then connected the high beam wire to the battery and the lights worked fine. Next I checked the voltage for the high beams at the main wiring harness and got 12 volts. It seems like it should work when the two wires are attached but still I just get dakness. When I attach a incandescent bulb to the high beam wire nothing happens but If I attach an LED light the LED lights up. Seems somehow I don't have enough power coming throught the wire to light the lights. I'm not sure where to go from here or what might even be able to cause the symptoms.
Anyone have any suggestions that might help?
Roachhill is offline   Reply With Quote
Old 03-23-2011, 09:54 PM   #2
Skoolie
 
sportyrick's Avatar
 
Join Date: May 2006
Location: mid Mo.
Posts: 241
Year: 1976
Coachwork: bluebird
Chassis: F33695
Engine: 427 chevy
Rated Cap: 84
Re: Need help with the high beams

It's probably the switch, you could get voltage but not carry enough current. sportyrick
sportyrick is offline   Reply With Quote
Old 03-23-2011, 10:17 PM   #3
Mini-Skoolie
 
Join Date: Feb 2011
Posts: 17
Year: 1997
Coachwork: Amtran
Chassis: International
Engine: T444E/Allison pusher
Rated Cap: 79
Re: Need help with the high beams

I would agree , replace the switch, especially since its both lights.
gseufzer is offline   Reply With Quote
Old 03-23-2011, 11:24 PM   #4
Bus Crazy
 
Join Date: Jan 2008
Location: Upstate NY (Mohawk Valley)
Posts: 1,096
Re: Need help with the high beams

If there is a high resistance, like a worn-out switch or a wire that is corroded, it will still show 12 volts at the lamp socket with the minuscule draw of a meter or test lamp. Test it again when it is supplying current. Pull the connector slightly off of a bulb, but not enough to make the lights go out. Stick the meter probe onto the connecting blades when the light is supposed to be on. A loss of voltage will show you if a high resistance is burning off the voltage when the bulbs start drawing amps.

Depending on the type, you may be able to make the same tests at the dimmer switch connection. If 12 volts comes out on the low beam pin, and little or nothing when selecting high, it's definitely the switch. If there is plenty of high beam voltage out of the switch with the bulb connected, but none at the headlight, the wiring is suspect.

In that case, feel along the wire for a bulge, a hard spot, or an area that won't bend as easily as the rest of the wire. If you find such a spot, chances are that there will be green powder instead of metal inside there. All it takes is a pinhole in the insulation at a wet location.

I would still suspect a worn switch is the most likely culprit.
__________________
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.
Redbear is offline   Reply With Quote
Old 03-24-2011, 05:16 PM   #5
Ob1
Skoolie
 
Join Date: Aug 2009
Posts: 187
Year: 1963
Coachwork: Grumman
Chassis: Chevrolet
Engine: Chevy 292 I-6
Re: Need help with the high beams

Might want to see if your circuit uses a relay to handle the high amperage lighting power needed, similar to the way the starter switch uses a solenoid to run the starter motor. Sounds like a relay with scorched contacts.
Ob1 is offline   Reply With Quote
Old 03-24-2011, 09:42 PM   #6
Mini-Skoolie
 
Join Date: Feb 2011
Location: Backwoods of Pennsylvania
Posts: 34
Year: 1999
Coachwork: Thomas
Chassis: International
Engine: T444
Rated Cap: 22
Re: Need help with the high beams

How would I know if it has a relay and where would I find it? I was just thinking the wire size at the lights is much larger than the wire size at the switch suggesting some sort of relay system but I wasn't aware they used relays in high beam setups. Of course I don't know much so their are tons of things in there I'm not aware of, LOL.
Roachhill is offline   Reply With Quote
Old 03-25-2011, 06:59 AM   #7
Ob1
Skoolie
 
Join Date: Aug 2009
Posts: 187
Year: 1963
Coachwork: Grumman
Chassis: Chevrolet
Engine: Chevy 292 I-6
Re: Need help with the high beams

To find out if it has a relay, check the electrical schematic. If you dont have the schematic, start tracing the heavy gauge wire from the headlights backwards...
Ob1 is offline   Reply With Quote
Old 03-25-2011, 10:33 AM   #8
Mini-Skoolie
 
Join Date: Feb 2011
Location: Backwoods of Pennsylvania
Posts: 34
Year: 1999
Coachwork: Thomas
Chassis: International
Engine: T444
Rated Cap: 22
Re: Need help with the high beams

So far I've removed and tested the high/low beam switch and it works perfectly so I'm down to the relay idea and that looks like the most likely answer. Now to find it. I don't have the luxury of a wiring diagram or repair manual yet but the wire at the lights is large and the wire at the switch is awfully small sugesting there's a relay in there somewhere. I followed the wire up from the headlight but that disappears into the main wiring harness then into the firewall so that's a dead end. The wire from the switch disappears under the dash. So anyone have any idea where the most likely place would be to start searching? Would it be behind the dash or under the hood. I hate to tear the bus apart randomly.
Roachhill is offline   Reply With Quote
Old 04-02-2011, 05:34 PM   #9
Mini-Skoolie
 
Join Date: Feb 2011
Location: Backwoods of Pennsylvania
Posts: 34
Year: 1999
Coachwork: Thomas
Chassis: International
Engine: T444
Rated Cap: 22
Re: Need help with the high beams

Just an update if anyone is interested. The other day the poor old skoolie got a flat ( and I got another hit in the wallet) So the mechanic at the company where I work took the wheel off and drove me to the tire shop, on the way we chatted about the problem. I mentioned the International dealer said the relays should be under the passenger side dash but of course the bus doesn't really have a passenger dash to be under. The mechanic said the company buses have their relays on the firewall next to the engine. When I got home I inspected the firewall more carefully and still didn't find what I was looking for so I went to watch TV. Later it occured to me something was odd about the corner panel that holds the turn signal so I went to check it out. One side has screws but the other has a hinge, It's a little door, Duh. Behind that I found the corroded connector that was causing my problem. Happy day all the lights are back on!
Roachhill is offline   Reply With Quote
Old 04-13-2011, 10:31 PM   #10
Mini-Skoolie
 
Join Date: Feb 2011
Posts: 17
Year: 1997
Coachwork: Amtran
Chassis: International
Engine: T444E/Allison pusher
Rated Cap: 79
Re: Need help with the high beams

dont cha love it when you actually find a problem!!!!! lol
gseufzer is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
High Mileage Gearhead94 Mechanical and Drivetrains 14 10-20-2012 02:51 PM
High RPMs? Accordion Mechanical and Drivetrains 17 10-09-2011 02:34 PM
HELP! RV to high GoneCamping Conversion General Discussions 0 06-20-2009 10:20 PM
How high should I go? josetann Everything Else | General Skoolie Discussions 3 09-05-2008 04:47 PM

» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 09:52 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.