Quad headlights, but Low Beams only work on High??

Posted By: ConvertiBee

Quad headlights, but Low Beams only work on High?? - 02/05/15 09:11 PM

On my '71 Cuda, the Low beams will not come on by themselves... ala carte. They DO come on when I also turn on the High beams...all 4 headlights do. At 1st I thought this would be a faulty floor switch, but I removed the switch and test-jumpered from the "Hot" wire that feeds the switch, and then into the Violet wire leading out, which the wiring diagram shows as going directly to the Low Beam side of the headlights.

Nothing!

What am I missing here? They've never worked since I bought this car a couple of years ago... I don't drive at night, but I WOULD like to get this fixed!
Thanks for your help in advance

Posted By: MoparforLife

Re: Quad headlights, but Low Beams only work on High?? - 02/05/15 09:50 PM

You do realize that on low beam there are only the 2 outside sealed beams that come on. The inner 2 sealed beams only have one element and it is wired to the high beam side.

Posted By: Supercuda

Re: Quad headlights, but Low Beams only work on High?? - 02/05/15 10:28 PM

Quote:

You do realize that on low beam there are only the 2 outside sealed beams that come on. The inner 2 sealed beams only have one element and it is wired to the high beam side.

To clarify the "low beam" headlights have both low and high beam filaments in them. Odds are your low beams are not coming on at all and you are seeing the highs in all four headlights.

I would look at your floor dimmer as that is where the switch is made and they do have a tendency to go bad being where the muck and wet is.

Posted By: therocks

Re: Quad headlights, but Low Beams only work on High?? - 02/05/15 11:01 PM

Are you sure the low side of the bulbs are good?Ive seen them burn out and the high side still is good.Time for a wiring diagram and test light if the bulbs are good on both low filaments.The inner highs only have 1 filiment thats why the lows have 3 pins and highs 2 pins.Rocky

Posted By: RapidRobert

Re: Quad headlights, but Low Beams only work on High?? - 02/05/15 11:35 PM

(1) push the dimmer switch to "low beam" & pull the connector off & see if the specific switch terminal is hot (2) if not clean or replace the switch (3) if its hot plug the connector back in & pull the connectors off of the low beam lights and see if the specific female connector terminal (the one from switch low beam terminal) behind each light is hot. (4) if not there is an open rearward to the dimmer switch (check bulkhead first) (4) if both are hot then ohm the male terminals on the low beam headlights to check for an open. I'm thinking there is 1 ground for each side of the vehicle (1 low beam/1 high beam), it's been awhile & it must already have continuity to ground as you are getting some filaments lit up but do some checking & holler back. EDIT the violet with tracer wire is the low beam circuit (1) see if it is hot at both low beam lights (dimmer on low) (2) if so pull the connector off of each low beam bulb and ground the bulb male lug the black wire connector was on & (3) jump fire to the high side (other end "red wire" male lug) & see if it lights up and (4) Then jump fire to the low side (middle male lug that the violet wire was on) & see if it light up (check both low beam bulbs) & not likely both lights went bad so see what develops

Posted By: MoparforLife

Re: Quad headlights, but Low Beams only work on High?? - 02/05/15 11:59 PM

I neglected to say in my first post that on high beam all 4 head lights should come on.

Posted By: ConvertiBee

Re: Quad headlights, but Low Beams only work on High?? - 02/06/15 07:12 PM

Thank you all, especially RapidRobert! I got it fixed... it was a little bit of everything: 1 bad bulb, a sticky switch, a crappy ground.
It's all working 100% now

Thanks!!