GRG

1967 small block with factory AC and electric fan behind radiator.
Last night was my second recent night time drive. My lights are just too dim and the misses was not real happy about that situation. My battery is almost new and I just had the alternator reworked to bring it up to 70 amps from the stock 37. The car always starts, no problem there. I thought the AC and the electric fan might be putting too much draw on the battery, so when I pulled up to the garage door last night, I turned off the AC which failed to make any difference as far as the dim headlamps. With the low beams only on, I noticed a very slight orange glow on the filament of the high beam lights. The high beam lights will turn on with the dimmer switch, but they are no brighter than the low beams. Are the high beams draining current off the low beams?? (see orange glow note above) Is there a ground problem? Where do I look? Note: I have a scissor switch on the negative post. Car always stays on trickle charger when I am not using it. Your thoughts please.

Frankie the Fink

Could just be old wiring or original headlights....
The original headlights were not the brightest even when new but I'm betting your voltage is dropping because of old wiring or corrosion in the headlight switch -- a common problem. Some use relays to deal with the issue. Some voltage checks may be in order.

Plenty of info on this issue on the Mad Electric tech portion of their web site...

Donald #31176

In addition to Frankies advise remove the headlamps and using fine steel wool clean the prongs on them. Also with an emery board clean the headlamp connectors and apply a coating of dielectric grease to the prongs. The other area to inspect would be the floor dimmer switch. Clean the dimmer with electrical spray cleaner.

leif.anderson93

Gordon,

You state that you have factory a/c and your stock alternator was 37 amp. One or the other can't be factory stock. Factory stock '67 vettes with A/C had a 61 amp alternator. But, you say you had yours redone to a 70 amp output so, if done correctly, that shouldn't be your problem. As Frankie stated, the original T3 headlamps were barely brighter than a candle to begin with but the high beams should definitely be brighter than an orange glow. I would start checking all your wiring and headlight switch for voltage drain. Sounds like you're not getting enough "juice" to the headlights. Do you have the original wiring harness in your car??

Nowhere Man

Did you put a meter on your alt and see what it's really putting out

6T5RUSH

What Frankie said. Here's a link at Mad Electric's site on this very subject:

http://www.madelectrical.com/electri...adlights.shtml

I did this 5 years ago. Along with swapping to halogen headlghts, big impovement!!



Jim
In God We Trust!

wombvette

Fact that it's bleeding over on the other filiment would suggest a grounding problem. Make sure you have good ground and add some if you need to.

Frankie the Fink

Yes. A good thought.
Check the wiring connections/grounds as well as prior advice

BD104X

I put halogen bulbs in mine but had the same problem - dim, yellow light and voltage bleeding into the high beams. I discovered some poorly soldered / repaired wires in the short harnesses that run from the main harness into the headlight buckets. Once I repaired those & all of the grounds the headlights were much brighter & the bleeding to the high beams stopped. It made such a difference that it makes me want to try the relay modification, I just haven't had a chance yet.

Frankie the Fink

Mad Electric says reducing voltage to the headlights (bad/old/corroded wiring, etc..) by 10% can reduce illumination by 30%. So, it doesn't take much of a problem to knock your headlights in the dirt...

65silververt

If you are running halogens, which you most likely are, you will need this relay kit in order to make the lights bright enough for night time driving.

I would go with the second kit with the weatherproof relays so you can mount it out of sight.

http://www.americanautowire.com/shop...ncer-relay-kit

http://www.americanautowire.com/shop...lay-kit-with-g

After38Years

When you put your lights on does your ammeter stay at zero or slightly positive? If not, check your alternator output with a voltmeter and see if its showing in the area of 14 volts...

TD's 64

You sound like you are having the same problem I had. After pulling my hair out trying to figure out what was going on, I discovered that the plugs for the headlight harness extensions were wired wrong by the manufacturer and did not match the pattern on the main harness.

High beams were energizing the low beams, low beams were energizing the ground and the ground was grounding the high beams. This created the same dull glow on the high beam inboard lamps when I was in low beam and dimmed the low beams when I was in high.

You might check whether this is your problem by testing the continuity from the firewall plug to the headlights. I believe the purple is the top right for the parking lamps, the third down on the right is the tan wire for high beams and the second down from the left is the green wire for low beams. Check your schematic to make sure.

65GGvert

the third down on the right is the tan wire for high beams and the second down from the left is the green wire for low beams. Check your schematic to make sure.


That should not be. The correct color codes should be tan for LOW beams and Green for HIGH beams. The tan wire should not go to the high beams at all, and the green should go to one filament of the lows AND the single filament of the high beams.

TD's 64

I am sure GGVert is correct. My point is check the continuity from the firewall to the headlight socket to make sure you don't have the same mismatched harness plugs I had at the headlight extension junction.