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Topic: High beam to low beam transiton (Read 1662 times) previous topic - next topic

High beam to low beam transiton

When i turn off auto lamp, the following happens.  This holds true with my white coug, my 20th anny and my son's 885.0.


When i manually switch from low beam to high beam pulling the lever all the way in, my headlamps are much brighter.  When i release the lever to allow it to fall into the hi beam detent, the brightness is less.  The same for going from hi to low beam.

What i mean is when i manually hold the lever all the way back towards myself, it appears i have more current going to the headlamps.
When I let the lever go, "some" of the current or illumination of the lamps is missing.

its like a high resistance issue somewhere.

It happens when i transition from hi to low beam or, from low to hi beam.  Ive wanted to discuss this for a long while now, I guess i never got around to it.
What i am trying to do is identify if there "is" or "is not" a problem.  Certainly it cant just be my cars that does this. 

I figured by turning off the auto lamp feature, this would help isolating the few components in the circuit.
I have a few spare parts, i am wondering if the thumb wheel resistance is effecting this or even the column lever switch itself.

any thoughts.

High beam to low beam transiton

Reply #1 –
That is normal as far as I know, as the bulb has two filaments so when the switch is pulled back it is lighting up the low beam filament as well as the high beam filament in the bulb. When you release the switch is it only lighting up one of the filaments as it is supposed to do to prevent the bulb from overheating since it was not made to run with both filaments on.

 At least that is what I have noticed in our '87 Cougar, and hope that is all it is...
1985 T'Bird 5.0
1987 Cougar 3.8
1992 T'bird Sport 5.0 HO

High beam to low beam transiton

Reply #2 –
Quote from: TheEskimo;377335
That is normal as far as I know, as the bulb has two filaments so when the switch is pulled back it is lighting up the low beam filament as well as the high beam filament in the bulb. When you release the switch is it only lighting up one of the filaments as it is supposed to do to prevent the bulb from overheating since it was not made to run with both filaments on.

+1
...and there was light!

High beam to low beam transiton

Reply #3 –
Concur.  Pulling back on the turn signal lever is the "flash-to-pass" feature which lights the high-beam filaments for as long as the lever is held (along with the high-beam indicator). If the low-beams are on, this would cause both filaments in each lamp to be lit at the same time. The 88 EVTM shows there is a dedicated relay for this function also.

High beam to low beam transiton

Reply #4 –
Don't hold the flash to pass, the Multi function switch will melt down. My sister had a Tempo, which the headlight switch died. didn't tell anyone, drove around for a month holding the flash to pass , that's how I know :rollin:

High beam to low beam transiton

Reply #5 –
Quote from: bullitt4514;377377
Don't hold the flash to pass, the Multi function switch will melt down. My sister had a Tempo, which the headlight switch died. didn't tell anyone, drove around for a month holding the flash to pass , that's how I know :rollin:

In the EVTMs they went to a relay in 85. 84 just uses the contact in the Muilti function switch.
I guess the Tempo was pre-85

High beam to low beam transiton

Reply #6 –
Jcassity....the older chevy trucks (like mine, which is an '88 with what could be called 4 eyes..) one can purchase a kit from LMC to enable the low beams to stay on with the highs. I've got this on mine...it definitely makes for better night time vision.

My point: if someone has a 4 eyed Bird/Cat...it could be adapted to work. Or one could be made, too.
'98 Explorer 5.0
'20 Malibu (I know, Chevy, but, 35MPG. Let's go brandon, eh)
 

High beam to low beam transiton

Reply #7 –
On the 4 eyes, the low beam bulb has two filaments. When the high beam is on it switches to another filament in the bub so you have all four sealed beams on. Though I know if the low beam filament was on in there as well it would be brighter, the bulbs may get too hot and cause something to give out or melt.
1985 T'Bird 5.0
1987 Cougar 3.8
1992 T'bird Sport 5.0 HO

High beam to low beam transiton

Reply #8 –
ah yes, all this makes sense,, thanks!