Headlight

My headlights on my 75 Superior ambulance only work on high beam and its not all four lights that come on just the inside 2, would that be a dimmer switch?
 
My headlights on my 75 Superior ambulance only work on high beam and its not all four lights that come on just the inside 2, would that be a dimmer switch?

Interesting situation. Do the low beams come on when you don't have the high beam ons? Where's Ed to get his thoughts.
 
Not sure when they started doing it, but on most of my four-headlight GM vehicles the low beams go out when the high beams come on. I can't remember what my 62 did, but I think it was the same way. Sounds like something is amiss in your low beam circuit.
 
Not sure when they started doing it, but on most of my four-headlight GM vehicles the low beams go out when the high beams come on. I can't remember what my 62 did, but I think it was the same way. Sounds like something is amiss in your low beam circuit.

On my 73 before adding the red headlights, when activating the hi-beams all fours lights stayed on.
 
You may be right. Now that I think of it, I think I have a picture of my old 69 wagon with all four headlights on. I don't think I modified anything for it to do that. I know the 90's pickups only ever have two lights on at a time, high or low.
 
Hi Chris...I had the same problem with my '73 Lifeliner. It was the floor dimmer switch. I pulled it off, cleaned all the contacts and made sure the wires were insulated well between each other and the floor after making the reconnections.

Electricity will do strange things when circuits are not "clean" and the ground is intermittent.

Good luck
 
Just checked the 75 thats been sitting a while. On high, only 3 lights came on, pumped it a few times and all 4 came on, so the dimmer switch was probably crusty.
 
From my 1972 Shop Manual

Chris...here is a page from my 1973 Shop Manual. I'd really suggest that you try and find one for your car...saves alot of grief and at least sends you in a reasonable direction for trouble-shooting.
 

Attachments

  • headlight issues0001.pdf
    202.7 KB · Views: 272
With the introduction of the halogen headlamp bulb units, there was a short period of time that the cars started being wired so only 2 of the 4 bulbs were illuminated at any one given time.. The interesting thing is that they just didn't use the high beam headlight circuit on the outer bulbs, and they just had two terminals hooked up to the 3 terminals on the bulbs. It would be an easy fix if your car was wired this way, by just installing a jumper wire from the hot wire on the high beam bulb (inner) to the high beam terminal on the low / high beam bulb (outer).
 
what is happening is when I turn the lights on the inner two most dont come on unless they are on high, but when on high thats when the inner two some one but the outer 2 do not.
 
what is happening is when I turn the lights on the inner two most dont come on unless they are on high, but when on high thats when the inner two some one but the outer 2 do not.

Open the hood, and look at the headlamp terminal, and determine if the outer headlamp has 2 wires or 3 wires going to it. If it has only 2, then that is the way it was engineered to work. If it has 3 wires, then the high / low dimmer switch is defective. This circuit is controlled from the headlamp switch, to the dimmer switch, to the headlamps.
 
all 4 should be on on high beam. gut got off the road in my 2010 and wished I had a 73. hate those new light systems at were designed for city streetlight driving. most likely the dimer switch but could be a number of things in a old car. the outer two are double filament bulbs the inner are single. half the time it the brass tag has come lose from in back of the bulb. you can re solder them on it it's that. corrosion on the connectors is another problem
 
On a 75 Cadillac, low beams are outer lamps only, then on high beam all four should be on.

The only exception would be if your car was rewired for red inner lamps or wig-wag flashing highbeams.

My thought is to check the foot controlled dimmer switch.
 
Mine does have the wig wags in them but I got them working last night it was the dimmer switch it had come loose a little. thanks for all the help. Now I just gotta figure out how to get a door open that the lock is missing and even turning the key in the lock on the outside of the door it will not open? any suggestions?
 
Back
Top