I am replacing my headlight switch, the new one does not have the small attachment at the bottom of the switch that the vacuum lines connect to? I ordered this one from PartsAmerica.com. I looked through some of my corvette parts catalogs and the ones that show a picture of the switch, do not show the vacuum line attachment? Anyone else replaced a headlight switch and if so were did you purchase it from?
I am replacing the switch because it gets real HOT when turned on.

Patrick Opsahl
Lathrop, CA
1982 CE
1973 454/4spd

 

I replaced mine, not too hard. The switch has to have the vacum ports or else the lights won't go up or down. You probably just got sent the wrong switch. I got mine from The Last Detail. About $40 I think.

 

Word of advice - it may not be just the switch at fault...

Sorry, I'm not tryin to scare you, but there could be more to the problem than meets the eye. Do you have halogen headlights installed?
The standard type of lights are the sealed-beam type. These give pretty poor illumination apparently, and don't draw much current. Many people take these out and replace them with halogen "h4" type bulbs. These are much, much better, but of course draw more current than the switch was designed for. (There's no fuses in the vette headlight system, just a circuit breaker inside the switch)

This can eventually fry your wiring loom, switch etc. and lead to things like a very hot switch as you're seeing. (Do your lights ever blink on and off, especially when you've had them on main beam for a while? That's another symptom)
The way to check is to take the headlight bezels off and/or have a look at the back of the headlights from underneath the car. The stock sealed beam lamps have terminals for the wires kind of "moulded" into the back of the unit, so you can't change the bulb - you just change the whole unit. If they're H4, then you'll see it is possible to remove the bulb, by pulling off a rubber boot and opening a wire spring clip.
If you still have the sealed beam units, then I'm not so sure why your switch should be heating up, but I'd check the condition of the wiring before replacing the switch. The switch itself is just that -- a switch. No more no less. It's hard to imagine what's going to go wrong with it. The heat would suggest too much current, indicative of a problem further up.
If you do have the H4 type bulbs installed, then the only "correct" way I know of to run these in the C3 is to use a system of relays which take all that load off the poor old switch. Have a little poke around and check the wiring/bulb type before you commit yourself to fitting a new switch (you could well cook that one too, otherwise)
I'm doing the relay job to mine at the moment, so I'd be really happy to help you out if it comes down to it..
Good luck!
:cheers:

 

Thanks! I will try to check it out tonight. I will still need to get the right switch, the one with vacuum connections.
Patrick Opsahl
Lathrop, CA
1982 CE
1973 454/4spd

 

Finnally check the headlights, had to finish the heater core and heater valve replacement first.
The headlights say halogen on them, with the headlight mechanism in the up position and the lights off I can read the words Sylvania Halogen on the outer lights and just Halogen on the innner ones. All say seal beam twords the bottom of the light. Looking inside the glass I believe I see a halogen type bulb in there? The back of the headlight looks like a regular headlight with the stock connector on it. I believe they are halogen but they seam to be in the standard seal beam configuration?
So, I am interested in your relay setup, can you tell me more on how you are installing?
I got my money back on the first headlight switch I purchased.

Something to add: When doing my heater core replacement I had the entire dash off, since my stock radio performance was so poor I added a ground wire to the radio case. Now it does not work and the power antena does not raise? Whats up with that?

Patrick Opsahl

 

Yeah, I never considered that you could get sealed beam type light units with halogen bulbs in them, but I guess that makes sense. Kind of a combo of the stock and H4 setup. If you can find a wattage value printed on the bulbs, you'll be able to find out how much current they will draw. The outer ones (the ones that are combined dipped and full) will have two values printed "xWatts/yWatts".
If you take the Wattage of one of the full beam bulbs, ie an inner one, and multiply by 4 you've got the full power of the system. The wattage is quoted at 12 volts, so divide this wattage by 12, and you'll get a current value. (Forgive me if you already know how to work out amps from watts!) The stock system draws about 16 Amps, I believe. So if it works out to much more than this and you'll be able to see where the problems are coming from. My bulbs are 60 watt. so at full beam i'm using 240 watts of power. P = IV, so I = 240/12 = 20. Doesn't seem like a lot more but it was enough to fry my switch eventually.

I'm right in the middle of building the new wiring for my halogens at the moment. Ordering the relays today. I won't forget you, and I'll put together some pictures and a wiring diagram in the next couple of weeks. It's all really simple stuff to do. The most time consuming part is probably stripping out the headlight doors to make for easier access.

As far as your radio goes, I'm not so sure about that. I would have thought the case was grounded anyway. What had you hoped to improve by adding an extra ground :confused: Sorry, must be missing something:)

To me it seems like you might have blown the fuse somehow. If i were you, I'd remove the ground wire for the moment, check the fuse and try the radio again. You can check that the case is grounded, in stock form, by measuring the resistance between the case and a known good ground. (With the radio multiplug plugged in!!) If the case is grounded, then you'll get a near zero reading.....

Catch you later.

:cheers:

 

Back to the non operational radio. Took it out today, all connections good. Radio fuse in fuse box good. The stock radio/ tape player has wiring diagram on the housing, found the 12 volt wire input and applied 12 volts, radio works and power antena works. Noticed the relay clicking behind the passenger seat during testing and disconnected during next test with external 12 volts, radio comes on but no antena. Deduct that relay is for antena.
Could there be another fuse inbetween the fuse box and radio? I did a continuity check from the radio fuse to the 12 volt input to back of radio, mega ohms on the fluke - mean anything?
By the way it is very difficult getting to the fuse box, who designed putting it so far up under the dash?
This car is frustrating me, now the battery looses charge after sitting for 2 days, it use to hold charge for at least 2 weeks before!

Patrick Opsahl
Lathrop, CA

 

Hmm, strange. I don't know of any other fuse between the radio and the normal fuse. Plus if there was one, and it had blown, then the reading on the fluke would be infinite I would have thought. I say grab youself a proper GM wiring diagram fro your year - the one I got for the 80 has saved me hundreds of pounds in the last year or so.
At least then you'll have a definite answer on what wires go where. Perhaps theres a melted wire in the loom, but of course the only way to check that would be to follow it back through...gulp.

See if the radio feed wire is has any continuity to ground, perhaps this is what's draining your battery. Maybe its been chafing away on something grounded in the dash, arced and melted.... :confused:

Other options for a flat battery - the timer that leaves the interior lights on after you shut the engine off, apparently this can drain the battery when it starts to go faulty.

Are you leaving your power antenna up at all? I put a remote switch on mine and learnt this the hard way. Whe the relay in the jack box clicks across to put the antenna up, it's drawing 0.2 amps, from memory. This can flatten your battery overnight.

Other than that, set your fluke to the high amps scale, put in series with one of the battery terminals and cable, with the engine off. There should be a current draw of only a few milliamps (radio memory, and perhaps the electronic alarm in the 82??) Seeing as your battery is being drained, you'll no doubt see more of a draw than this. So start pulling fuses one by one until you notice a drop. The you've isolated the circuit where you have a problem.

Good luck its going to be a pain in the butt, but made so much smoother if you can track down a good GM wiring diagram...


And yep, that fuse box is in a bitch of a place!