OEM headlight switch...need help

lightn95

lightn95

Well-known member
I've got a question for anyone familiar with these switchs. Mine is getting extremely hot, it's actually smoking, only when I turn on the lights. There is a white ceramic wheel whither a spring inside of it. That's what's getting hot. Any ideas what would cause this? The lights still work.
 
That’s a known issue w/switch design in these trucks - believe there’s a TSB on it. Steve83 has an article about it on his Supermotors site. New switches are still available last time I checked.
 
lightn95 said:
I've got a question for anyone familiar with these switchs. Mine is getting extremely hot, it's actually smoking, only when I turn on the lights. There is a white ceramic wheel whither a spring inside of it. That's what's getting hot. Any ideas what would cause this? The lights still work.
Click to expand...
Old style wiring it's common. All power is run through the switch instead of a modern relay type system. Several companies make a harness that pulls direct from battery to correct this problem. I'd say switch and get a harness and you'll be good to go.

Sent from my SM-G955U using Tapatalk
 
That ceramic disc with the copper coil is a rheostat for your dash lights. The spring starts out loose which provides high ohms for low light and low ohms for brighter lights. If that's getting hot there's a short most likely in the dash lights or faulty switch.
 
lightn95 said:
I've got a question for anyone familiar with these switchs. Mine is getting extremely hot, it's actually smoking, only when I turn on the lights. There is a white ceramic wheel whither a spring inside of it. That's what's getting hot. Any ideas what would cause this? The lights still work.
Click to expand...
I had the switch crap out on me on the pa turnpike at night going home. Had to hold the switch half way in to work. I replaced it and so far so good. That was about 5 or 6 years ago. When I took it apart it was all melted looking. Maybe I should look into getting a new updated one as well.

Sent from my SM-G965U using Tapatalk
 
I just got a new switch and it's still doing it. This is in the race Truck so I'm only using a couple of the wires. Dimming lights for the guages and head lights. It's been wired for about 5yrs and it just started last night.

If it turn the knob to turn on the dome lights ( not used) it blows the fuse immediately.

How do I find a short?
 
lightn95 said:
I just got a new switch and it's still doing it. This is in the race Truck so I'm only using a couple of the wires. Dimming lights for the guages and head lights. It's been wired for about 5yrs and it just started last night.

If it turn the knob to turn on the dome lights ( not used) it blows the fuse immediately.

How do I find a short?
Click to expand...
Hmmmmm...........that's weird. Maybe fast eddy can chime in here since he is our guru on electrical stuff.

Sent from my SM-G965U using Tapatalk
 
lightn95 said:
I've got a question for anyone familiar with these switchs. Mine is getting extremely hot, it's actually smoking, only when I turn on the lights. There is a white ceramic wheel whither a spring inside of it. That's what's getting hot. Any ideas what would cause this? The lights still work.
Click to expand...

I saw the subject, so I came to to reply: Pull the switch out and the headlights come on. Push it in they go off :) :) :)

- - - Updated - - -

lightn95 said:
I just got a new switch and it's still doing it. This is in the race Truck so I'm only using a couple of the wires. Dimming lights for the guages and head lights. It's been wired for about 5yrs and it just started last night.

If it turn the knob to turn on the dome lights ( not used) it blows the fuse immediately.

How do I find a short?
Click to expand...

OK serious reply, do you still have the dome light? If so pull the bulb or pull the plug that goes to the dome light. If that doesn't work I'd follow the wire from the dome light down until you find where it is bare or pinched, that would be my guess.
 
Raymond_B said:
I saw the subject, so I came to to reply: Pull the switch out and the headlights come on. Push it in they go off :) :) :)
Click to expand...

You know, I saw you replied and really thought you would be helpful....then I read this.......you really know how to kick a guy when he's down don't ya....
 
There's a power into the switch for the parking lights ( back lights for guages)......power wire to the guages.....a ground wire......a power wire into the switch for the head lights.....a wire to the head lights....
 
I disconnected the 3 wires that have to do with the "parking lights"....only the head lights on and it's ice cold..
 
Ok so I wired the switch to a battery on my work bench....in the driving lights only position.....positive in and ground to negative on the battery and it did the same thing...but alot faster.....spring actually started glowing.....WTF is going on here....
 
Anyone with a wire diagram, can you tell me what the White with Light Blue wire is for....Looks like pin #294....
 
lightn95 said:
There is a white ceramic wheel whither a spring inside of it. That's what's getting hot.
Click to expand...
There's a short in the dimmed dash circuit, or (more likely) the courtesy circuit.
lightn95 said:
....positive in and ground to negative on the battery and it did the same thing...but alot faster.....spring actually started glowing.....WTF is going on here....
Click to expand...
Stop doing that - you're damaging the switch AND the battery. You'll be lucky if you don't damage yourSELF!

The first place I'd look for a courtesy fault is the driver's threshold, near the B-pillar. Water collects there, corroding the wiring into green slime. This pic is from a Bronco - your belt reel is much higher:


(phone app link)

The next place would be the dome lamp screws, as described in this TSB:


(phone app link)
lightn95 said:
Anyone with a wire diagram...
Click to expand...
Free here, and you don't have to give them a real e-mail:
http://www.bbbind.com/free_tsb.html
 
You must log in or register to reply here.
Back
Top