[InfiLights]

Hi all,

Getting ready to take the bus out of the storage place, got H4 LED bulbs and thought it is time to do an upgrade.
As I change bulbs, before I put everything together, I have to test them.....no low beams...both sides, no power to the bulbs sockets.
I have the quad headlight setup with Ford Bronco elements, each headlight has a H4 dual filament bulb. I can get the inside pair (high beam) to light up if I pull on the turn signal stalk...but no low beams. Parking lights OK, turn signals ok, marker lights ok...no low beams. Puzzler...

Checked the fuses, the high and low beam circuits both go through a self resetting 25 amp fuse each, separate for high and low beams. Both Breakers are good. I have 12v power leaving the breaker but not getting to the bulbs. If there was one only I would think I have to look for a broken wire or no contact...but both ? I can not find in the diagram a headlight power relay...is there one somewhere ?

So...what am I missing ? Is there a release relay somewhere that allows lights to come on when the bus is in Drive only, or Parking brake disengaged and I don't know about it somewhere ?

Anybody had this happen ?

Another thing I just noticed is that the high beam blue light indicator on the dash does not come on when the high beams are on....it should...I will pull that bulb out after I take the dash cap off and check it out...

Any suggestions ?

[encantotom]

a couple of thoughts.

it is possible the polarity of the 12v and ground on the plug is reversed. remember, with a halogen bulb the polarity doesnt matter. on led's it does.

first of all make sure your bulbs are good.

then check the polarity of the high beams with a volt meter and make sure the polarity of the low beams are the same.

on my hot rod, the flashers didnt like the led turn signals i put in. so i put a 12v relay on the circuit, not to switch anything but to give some load that then would allow the turn signals to flash. added benefit is it now makes a ticking sound like a real turn signal...ha

point to all of this is led lights are finicky.

there are a few threads on the forum about optimizing headlights. has alot to do with more voltage (minimizing voltage drop) to the headlights. various ways to help including bigger wires, dedicated wires, additional relays etc.

tom

[InfiLights]

I took the LED bulbs off and put new Halogen bulbs in the sockets....still no low beams regardless of what bulbs I use......, no power to any wires in the low beam sockets both sides. High beams, fine... ground, 12v power, all good, both sides......What the heck ?

[Fulltiming]

Check the dimmer switch adjustment at the base of the steering column. If it gets out of adjustment you will lose either low or high beam lights. If you have high beams the light switch on the console is working. If you can't get voltage out of the low beam side of the dimmer switch, it can be easily replaced. I recall it is off a Ford F-150 from the late 1980's. I got one at the Ford dealer in Yuma when mine went out several years ago during a trip from Texas to California.

[Richard]

My first guess is with Michael. Check the dimmer switch. Especially since you mentioned tugging on the turn signal activated the high beams. You could hotwire around the dimmer switch to check for function.

[InfiLights]

How does this dimmer switch look like ?
My headlights are on a paddle switch on the left side of the driver panel. Parking lights in up position, Off in the center and Headlights in the flipped down ( low) position. I do not see any dimmer down below unless it is hidden behind the panels in the driver footwell.....Is that where to look for it ?

I do see 2 dimmers for dash lights and post lights, higher up on the dash left side, but nothing that I can tell has to do with the headlights ...

Anybody got a picture of this dimmer switch at the base of the steering column ? Maybe mine is mounted somewhere else and I have to find it...    

[House Divided]

[attachment=7639]My switch is located on the left side of the column,  down towards the bottom. It is the white plastic piece in the photo. Look for the steel rod that actuates the switch when the dimmer lever is toggled.

[Fulltiming]

You have to remove the surround that covers the lower part of the steering wheel column down to the floor to see the headlight dimmer switch. David's photo looks like mine.

[InfiLights]

Many thanks. I will look for it tomorrow

[InfiLights]

Thank you Michael.....right ON ! That switch is funky, some corrosion I guess but I sprayed some contact cleaner and played with it a few times, then all of the sudden we have lights !!!! Both Low and high beams, the high beam dash light comes on as well now.....That switch is OK now....but maybe down the road it may need to be changed if it is acting up again.

To all that chimed in and offered suggestions , thank you. The power of this community and the help is greatly appreciated.