My headlights are dim on both beams. The high beam indicator light in dash stays on bright. I have restored lenses, replaced bulbs with higher quality bulbs, replaced headlight switch and blinker/ high-low beam switch as well as fuses. Research indicates a bad ground but I have cleaned all grounds as well. I am baffled at this point. The truck is for my 16 year old to drive but it is not safe for him at night. Any help would be greatly appreciated.

Chris

 

Can you explain that in greater detail?

Are you saying that the filaments are switched properly but are not as bright as expected? Or that when you toggle between them, the low beam filament stays illuminated and the high beam does not come on?

Is the truck a Sport model?

Does it have the daytime running lights option?

How proficient are you at electrical troubleshooting? Do you have or can you get a VOM (volt-ohm-milliammeter) to apply to the effort?

 

your level of mechanical ability will determine your course of action. my suggestion would be to use a relay and power the lights from the battery. you may have a wire pinched in the tilt column

 

So, if there's a pinched wire it should be left alone to eventually fail rather than being fixed right the first time?

I agree that a relay kit is a good choice, but I, personally, would never even consider sending a kid I care about out into the world in a vehicle that might just lose its headlights without warning. Save a buck, lose a kid?

 

It is an SLT model. Both high and low beams work but are very dim. The blue dash indicator light stays on high on both beams. I am far from proficient but can get a VOM and help from an electrician friend.

 

Bad ground, which the switch provides. Grab the service manual from the faq section, look at the wiring diagrams, find the correct ground, and make sure it is good.

 

I just printed them. I will try that next. Thanks.

 

Are the dash lights flickering? Heater fan goes faster when you accelerate? If either of those then your alternator is on it's way out... I had that happen twice, in one case bad enough to render the whole engine unstable.

 

Im going through the same thing now...indicator light stays on but for me i notice when switching high to low beams indicator glows slightly brighter....also while blinding to look at...both filaments are being lit...

when pulled up to wall switching between high and low does not change the angle of the beam but instead only affects brightness,

voltage test of the wires indicates voltage on all three wires 12+ volts on the outside wires (for me thats the red with orange stripe and the purple with white stripe) and about 4 volts on the center wire (purple with red stripe)

my truck is a sport, has a one piece light. My thoughts are a bad ground (daytime running lights also had bad ground as well as the right blinker..managed to fix those but still sorting through this one.)

See if there are any similarities between us..we will work through this together ;}

 

I don't know why it didn't occur to me until just now: Verify that the bulbs you've got installed are the correct part number. In a non-Sport model like yours they should be 9004 or equivalent. Sport models get 9007's. Though the plugs will fit, they're not interchangeable. If they're 9004's:

First test is to look at B+ going to the lamps -- the way these things are wired up, as the schematic shows, is with B+ being common to both filaments, with ground switched to the desired filament via the headlamp and dimmer switches. So probe that common connection, and turn on the lights. If the voltage stays near battery voltage (as measured right on the battery and with the headlights on) then your fault is on the ground side of things. If, on the other hand, the voltage drops very significantly, then your fault is on the battery side and much easier to troubleshoot because there's less stuff to fail.

Alternatively, or just to confirm the observations in the above test, you could probe the filament side of things and look at the voltage there with the lights on. It should fall to within about a volt or so of ground. If it doesn't, then the fault is on the ground side of things -- if it does, the fault is on the battery side.

If your electrician friend isn't up on chasing automotive schematics, figure out which way we're going with the above tests and we can work our way through to the fix. It'll be a bit slow because I'm not sitting here eagerly reloading this page all day, but we'll get there.