1970 Low beam issue
Thread Starter
Pro
Joined: May 2006
Posts: 573
Likes: 5
From: Georgetown Township MI
1970 Low beam issue
Greetings!
I have an electrical problem that I need to address this spring.
With the car running, I turn the headlights on in low beam, they
go up but only the passenger side low beam comes on.
When I depress the high beam switch on the floor,
all of the lights come on. I replaced the headlights last summer,
thinking that was the problem but it didn't fix the problem. So I'm guessing
it's a wiring problem. Any troubleshooting suggestions would be appreciated.
Hopefully in the next couple of weeks,
I can get the car out of storage and can start getting to work on it.
Thanks.
I have an electrical problem that I need to address this spring.
With the car running, I turn the headlights on in low beam, they
go up but only the passenger side low beam comes on.
When I depress the high beam switch on the floor,
all of the lights come on. I replaced the headlights last summer,
thinking that was the problem but it didn't fix the problem. So I'm guessing
it's a wiring problem. Any troubleshooting suggestions would be appreciated.
Hopefully in the next couple of weeks,
I can get the car out of storage and can start getting to work on it.
Thanks.
Intermediate
Joined: Mar 2009
Posts: 40
Likes: 0
Greetings!
I have an electrical problem that I need to address this spring.
With the car running, I turn the headlights on in low beam, they
go up but only the passenger side low beam comes on.
When I depress the high beam switch on the floor,
all of the lights come on. I replaced the headlights last summer,
thinking that was the problem but it didn't fix the problem. So I'm guessing
it's a wiring problem. Any troubleshooting suggestions would be appreciated.
Hopefully in the next couple of weeks,
I can get the car out of storage and can start getting to work on it.
Thanks.
I have an electrical problem that I need to address this spring.
With the car running, I turn the headlights on in low beam, they
go up but only the passenger side low beam comes on.
When I depress the high beam switch on the floor,
all of the lights come on. I replaced the headlights last summer,
thinking that was the problem but it didn't fix the problem. So I'm guessing
it's a wiring problem. Any troubleshooting suggestions would be appreciated.
Hopefully in the next couple of weeks,
I can get the car out of storage and can start getting to work on it.
Thanks.
Thread Starter
Pro
Joined: May 2006
Posts: 573
Likes: 5
From: Georgetown Township MI
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Most likely a bad "new" headlamp. Switch the right and left side low-beam lights and see what happens. {Betcha' the left one won't work then...} But, if the right one still doesn't work, it has to be a power feed or wiring problem. If the ground were bad, the hi-beam wouldn't work either.
Drifting
Joined: Dec 2004
Posts: 1,345
Likes: 3
You can check the ground with an ohm meter from the black headlight socket wire to the frame.
Since the high beams work on all lights and you have replaced the bulbs it sounds like you could have a fault in the low beam wire. To check, this out, first check continuity on the bulb that won't light (defective new bulbs are possible, if improbable).
To check the wirubf use a volt meter on the low beam wire using the ground wire AT the headlight socket. If it doesn't light up try a second ground. If it still doesn't work you need to trace the low beam wire back to find the fault.
Good Luck!!
Since the high beams work on all lights and you have replaced the bulbs it sounds like you could have a fault in the low beam wire. To check, this out, first check continuity on the bulb that won't light (defective new bulbs are possible, if improbable).
To check the wirubf use a volt meter on the low beam wire using the ground wire AT the headlight socket. If it doesn't light up try a second ground. If it still doesn't work you need to trace the low beam wire back to find the fault.
Good Luck!!
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Bear with me on this; I did not pull a schematic. From my memory if the passenger side beam is coming on, the first place I would check is the wires behind the lamp. The connector has a jumper wire that runs from the driver side to the passenger side of the car. I personally have had this exact same problem and the solution was the connector as shown in the picture below.
The current that feeds the low beam side of the bulb splits off right at the connector, if the wire or the terminal is damaged and not making contact with the driver side bulb the passenger side will still work.
This reason all four lamps work on high beam is simple, the high beam is a different wire to the low beam bulb.
The current that feeds the low beam side of the bulb splits off right at the connector, if the wire or the terminal is damaged and not making contact with the driver side bulb the passenger side will still work.
This reason all four lamps work on high beam is simple, the high beam is a different wire to the low beam bulb.
Last edited by Willcox Corvette; Apr 2, 2009 at 08:51 PM.
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Thread Starter
Pro
Joined: May 2006
Posts: 573
Likes: 5
From: Georgetown Township MI
Gentlemen,
I appreciate all the input and the schematic will help a lot.
I didn't mean to be rude in my earlier response to Dr Corvette.
As for the "new" lamp bulbs, when I first noticed the failure,
after I replaced the bulbs, I thought the same as you guys,
so I swapped out the bulbs on the side that didn't work
and I had the same result.
I hope to tackle this in a couple of weeks. I was pro-active last fall and
ordered (4) new lamp bulb connectors thinking that may be the problem.
It could also be the wiring as well.
I appreciate all the input and the schematic will help a lot.
I didn't mean to be rude in my earlier response to Dr Corvette.
As for the "new" lamp bulbs, when I first noticed the failure,
after I replaced the bulbs, I thought the same as you guys,
so I swapped out the bulbs on the side that didn't work
and I had the same result.
I hope to tackle this in a couple of weeks. I was pro-active last fall and
ordered (4) new lamp bulb connectors thinking that may be the problem.
It could also be the wiring as well.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
OK. The bulbs are 'good', so you first need to determine if 12 volts are getting to the "problem" socket. Remove the lamp from the socket, turn high-beam lights on, connect negative lead to your voltmeter to a know good 'ground' location, then probe the socket for 12 volt signals. If you don't get 12 volts at the two contact points {the third contact is a ground connector}, unwrap the harness tape a few rounds to check voltage in the wiring [a few inches behind the socket]. Use a sharp pointed probe to poke through the insulation so that you can contact the wire; or stick a needle into the wire and touch your + probe to that. On the driver's side, the tan wire is the Lo-beam feed and the light green wire is the Hi-beam feed. If the tan wire is not "hot", your problem is likely in the [foot operated] dimmer switch on the driver's floorboard. If you get to that point, use your voltmeter to check the ouput of that dimmer switch before you remove it. If you get power there, but not at the socket, it must be a 'break' in that tan wire somewhere. Good luck.
Safety Car
Joined: Sep 2007
Posts: 4,458
Likes: 331
From: Indy Indiana
since one low beam works and does not follow the bulb then you have power in the tan wire from your foot switch.. I agree with wilcox that you have a bad or open connection at the plug-in for the non operational headlight... the tan wire feeds the system to the left hand side connector and then this connector splits/splices the wire to your passenger headlight that does work... seems it has to be the left plug-in since the right headlight works... I have actually used an emery board to clean the connections at the headlight.. this might be your problem.. make sure the connection is good and clean and that there is voltage at that terminal