I need some help with my dodge ram 1996 model wiring the low beam on headlights to stay on when the high beams are switch on.
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Connell Trotman
Connect the low beam to the beam switch - before the dip switch.
The dip switch then becomes and on-off switch for the hi-beam.
The other mod that may be required is that the low beam come on with the hi-beam or pass/flasher. Run a diode from the high-beam signal to the low beam relay coil (and insert a diode between the beam & low-beam relay coil to prevent the flasher powering the park lights if that's an issue....).
If you don't have relays - fit them - it's better & cheaper than a hi-powered diode.
Doesn't that truck have a single lamp housing per side? If so, the extra heat will not be good. Well let me rephrase that. it will be bad. If and only if you have a separate high and low beam housings this will do what you need.
The following link is for a Chevy truck. They switch power to the headlamps. i think your truck switches ground. Let me know if you need the drawing modified to work with a negative switching system.
https://www.the12volt.com/installbay/forum_posts.asp?tid=104435&KW=relay+low+beam+both
Idiot - thanks for the sanity check & experience.
Yes - if hi & low are the same bulb, the bulb will die fast. Maybe explode if it is halogen.
If hi & lo are separate bulbs but in the same shell, then the shell is likely to overheat and melt or cause fire....
I assumed a 4-headlight system (like my truck.)
Spark said likely. I say definitely. On the melting portion of it anyway. I have never heard of fire, but it will melt.
If you are simply using them as passing lamps, on for 10 to 15 seconds, you may be OK, but if they remain on for minutes at a time, you will have issues. Everything today is built to barely withstand normal use. They know how much heat the lens has to dissapate. They will not make anything strong enough to dissapate 160% of the heat it expects.
Some lights/lenses do - but I'm thinking of Bi-Oscars (separate H1 hi & lo (technically "fog") and people used to run 2 x 100W or 130W) and they are far from a "normal" headlamp.
I have also seen dual bulb/dual reflector 7" rounds do quite well, but they may have been 2 x 55W.
But they are not common (OEM - but in Italian sports cars etc).
But as I said, I was assuming SEPARATE shells & lenses.
As to an H4 running both - you are correct - NOT for long!
As to fire - only the insulation. Not that I've seen that. (But I have seen a exploded halogen lens - in the boot lid of the car in front!)