73 Headlights cutting out while driving?

[Joe R.]

Re: 73 Headlights cutting out while driving?

Thanks Joe,
Im not really an electronics guy, but I should be able to perform these checks you've suggested. I'm thinking that I may have a faulty low beam, and I blame myself for purchasing used lamps to cut costs. The low beams had some fogginging when purchased and one of them looked like one of the plug prongs had been re- soldered. Now, i noticed that the fogging in the low beam that is not coming on has gotten worse and there is even a blackish/smokey color in the bulb Maybe this bulb could be causing the wires to heat up going to the switch thus throwing the breaker I still have the replacement halogen bulbs I took out, so I'll plug it back in to see if things work as they should. I did purchase two brand new OEM (old stock)high beams. I have also just purchased two new OEM( old stock ) low beams. Waiting for them to ship out.

Question : when I bench test the bulb do I clip the ground wire in the center prong of the bulb and touch the positive wire to one or both of the other prongs to check if it works?
- As for the amps on my light switch not sure? Just purchased from one the of popular vette vendors.
thanks so much for your help!

Hi Jimmy,

If the bulb is not coming on, it is not drawing current, therefore it is not helping to cause the circuit breaker to pop. I don't know the pinout on your connectors, but assuming 12 V and ground are present at the connector, if you duplicate that on the bench, the lamp should light up. Do you know the GM part number of the switch? If you punch that into the search engine here it may give you how many amps the circuit breaker is rated at.

Joe

[Jimmy P.]

Re: 73 Headlights cutting out while driving?

Thanks Joe,
I bought the switch back in December from Corvette Central.
The CC Part # is 593062
The GM Part # is 1995191
I asked CC for the amp rating on the switch.
I will also check in the search engine.

[Bob R.]

Re: 73 Headlights cutting out while driving?

The low beam bulbs have two filaments in them they can appear to be out when in the low beam mode and when you hit the hi beam they can light up. With a bad connector and used bulbs I think you have found the problem. I would never get used bulbs they dry out and the vacuum seal fails then you get the puff of smoke in the bulb that fogged up look you mentioned.

[Ralph P.]

Re: 73 Headlights cutting out while driving?

Dimmer Switch will cause exact symptoms! NOS switches easily available & may be better than parts store replacements.

[Jimmy P.]

Re: 73 Headlights cutting out while driving?

Thank you all for all the input and helpful suggestions, as soon as I can get time to work on it I will report back with what I found out. BTW I was just in your neck of the woods Joe R. My wife and finished up our mid west vacation in St. Louis. We toured the great city and went up in the Arch and also got to attend the Steelers / Rams game. We stayed right behind the stadium in the Holiday Inn convention Center. I did ask some locals if anything was left of the old corvette assembly plant and was told that there wasn't anything left to see.

[Jimmy P.]

Re: 73 Headlights cutting out while driving?

Well, I had time to work on the car today and found the problem to be the headlight switch. I checked the wiring and everything seemed to be fine. I started the car and turned on the lights (all four) and left them on and watched to to see if they would cut out. After about 5-10 minutes all four lights went out for a few seconds and came back on. This happened over and over until I shut them off. One of the two used low beam lamps had a burnt out low beam filament. I just received two NOS Power Beam Guide lamps this morning that I found online. So, I replaced the used fogged lamps with the new ones and followed the same procedure. After about 5 minutes all the lights went out / came on then off. So, I replaced the switch with the old one as Jim T. suggested earlier in the thread and left the car run for about 20 minutes or so and the lights never cut out. The trouble with this switch is that the vacuum part of it doesn't work, I have to use the bypass to raise the lights. Bought the bad switch from CC in December and they say switches are non-returnable. I did email them to see what they say. Their switches come from Lectric Limited. Any suggestions on where to get a better switch if they won't refund/exchange?
On a disappointing note after about the third test with all NOS lamps, one of the low beams I just purchased smoked a little in the top part of the bulb. The original boxes were never opened. From what I've read it appears that air got inside somehow! How does that happen? I looked the bulbs over and they were in what looked to be new condition. Is it possible to get NOS lamps without some type of issue? This is getting expensive$$$/ and very, very frustrating.
These kind of things make me just want to give up on trying to get things just right for judging

[Joe R.]

Re: 73 Headlights cutting out while driving?

Hi Jimmy,

I'm glad you had a nice St. Louis vacation and got to see the Steelers beat the Rams. The Corvette assembly plant is in a very bad neighborhood, nothing to see there. The Carter carburetor plant was also in North St. Louis, it got knocked down recently. The arch is fun, one time I went up to the top with my sister. I was feeling kind of ornery, so I rocked the car on the way up. I don't think my sister was too upset, but some of the innocents on the same car were not very happy with me by the time we got to the top!!!

Joe

[Joe R.]

Re: 73 Headlights cutting out while driving?

Well, I had time to work on the car today and found the problem to be the headlight switch. I checked the wiring and everything seemed to be fine. I started the car and turned on the lights (all four) and left them on and watched to to see if they would cut out. After about 5-10 minutes all four lights went out for a few seconds and came back on. This happened over and over until I shut them off. One of the two used low beam lamps had a burnt out low beam filament. I just received two NOS Power Beam Guide lamps this morning that I found online. So, I replaced the used fogged lamps with the new ones and followed the same procedure. After about 5 minutes all the lights went out / came on then off. So, I replaced the switch with the old one as Jim T. suggested earlier in the thread and left the car run for about 20 minutes or so and the lights never cut out. The trouble with this switch is that the vacuum part of it doesn't work, I have to use the bypass to raise the lights. Bought the bad switch from CC in December and they say switches are non-returnable. I did email them to see what they say. Their switches come from Lectric Limited. Any suggestions on where to get a better switch if they won't refund/exchange?
On a disappointing note after about the third test with all NOS lamps, one of the low beams I just purchased smoked a little in the top part of the bulb. The original boxes were never opened. From what I've read it appears that air got inside somehow! How does that happen? I looked the bulbs over and they were in what looked to be new condition. Is it possible to get NOS lamps without some type of issue? This is getting expensive$$$/ and very, very frustrating.
These kind of things make me just want to give up on trying to get things just right for judging

Hi Jimmy,

Your scenario does sound very, very frustrating!!! I suspected the circuit breaker in the repro switch was too weak, I'm glad you figured it out! It's too bad the vacuum side of the original switch does not work. Did you already try searching on here using the GM part number? Maybe ask guys in your chapter that have or have had cars with the same switch. Or contact the 73 team leader for ideas? Maybe ask Patrick Hulst or Paul Oslansky?
As far as the bulbs go, are reproductions available? If I were you, I think I would be very tempted to live with a hopefully minor point loss rather than chasing NOS bulbs around the mulberry bush with my credit card. I think what happens is they lose their vacuum due to age / vibration, then it's all over but the crying!
Joe

[Jimmy P.]

Re: 73 Headlights cutting out while driving?

Joe,
I did check on here by using the gm part number and all that came up was that it is a GM replacement that has been discontinued. Dr. Rebuild has it as a GM reissue for $75.00 plus s/h. CC said that I could return it. Not sure I want to try another aftermarket? I also agree with you about the headlights, not going to buy the NOS lamps again.
BTW that ride up to the top of the arch in that 5 seater pod was interesting. I couldn't imagine getting stuck in there, or having to walk the stairs up or down for repairs or servicing.
thanks again,
Jim

[Joe R.]

Re: 73 Headlights cutting out while driving?

Hi Jim,

I had another thought, did you try the Restorer DVD? Or you could ask Vinnie Peters if anyone has done a Restorer article on how to repair that switch.

Joe