I have chosen Hella lamps (see below) to serve as driving lights on my 1979. Pretty sturdy construction and complete with all the installation components. My intent is to place the lights behind the grills. For Canadians, Canadian Tire is the source.





Before I get started I have a few questions on the wiring. The instructions (below) suggest tapping into either the low- or high-beam wiring with a scotchlock. I conclude from that that the driving lamps will be activated only when the headlights are on. I wish to run the lamps separate from the headlight circuitry and be activated only by the on-off switch. So how can I set this up? My inclination would be to simply ignore the green wire from the switch to the headlight wiring. I would still have power from the fused link to the battery thrrough the relay and on to the switch. And the switch itself would be grounded. Does that make sense?

Also I cannot see how to connect the hot wire to the battery sidepost. The post is too large. Is there another switched hot battery lead to tap into. I want switched so the lamps can only be operated when the car is running. Finally, what is the purpose of the relay? Many thanks for your help!
http://temp.corvetteforum.net/c3/pau...ctions_001.jpg

[Modified by paul79, 11:49 AM 8/31/2002]


[Modified by paul79, 12:04 PM 8/31/2002]


[Modified by paul79, 9:20 PM 8/31/2002]

 

To start with... the relay allows a low power circuit to control a high power circuit.

In other words using your situation as an example, you connect the driving lights directly to the battery, and it is controlled by the headlight circuit. If you tried to connect the driving lights directly to the headlight circuit you would blow the headlight circuit. (The fuse would blow before the wires melted down.)

Now for that green wire... yes, the way the instructions are laid out they suggest you wire this to the headlight circuit so that the driviing lights can only be operated when the headlights are on.

If you want to control the driving lights by the switch only... just connect the green wire to any positive source. (Please make sure whatever you connect it to is protected by a fuse.)

If you want to have the driving lights available when the key is on, then connect the green to any ACC fuse at the fuse box. If you want to have the driving lights available anytime (key off or on) then connect it to a fuse that has power all the time.

Now where to connect that big ol red wire. The battery is the best place to go to connect this up.

However, you don't have to go all the way to the battery but you need a circuit that is capable of handling the load requirements of the driving lights (in addition to the normal load the circuit supplies.)

Without knowing the power requirements of your lights and assuming they are modern halogen (or equivalent from a power rating standpoint) you could probably connect this up to the horn relay. The horn relay acts as a main power distribution block (the connection where all the 10 guage (big wires) come together.

Be careful and disconnect the battery before playing with live wires.

Have fun and let us know how they turn out. (Pictures if you can.) :cheers:

 

Thank you for the thoughtful reply! The bulbs are E11 halogen rated at 55W. Why does the circuit need two power sources: one to an ACC source and the other to the horn relay? There is one wire (orange) at the horn relay that is hot at all times. Is that the candidate?




[Modified by paul79, 2:17 PM 8/31/2002]

 

Here is my attachment point with drilled holes.



And one side mocked out and done.



The lamp can be adjusted left-right and tilt forward/back because of the way the brackets are configured. I have to do some alignment on the grille.



[Modified by paul79, 4:05 PM 8/31/2002]


[Modified by paul79, 4:08 PM 8/31/2002]


[Modified by paul79, 4:10 PM 8/31/2002]


[Modified by paul79, 8:45 PM 8/31/2002]


[Modified by paul79, 8:46 PM 8/31/2002]


[Modified by paul79, 8:47 PM 8/31/2002]


[Modified by paul79, 8:49 PM 8/31/2002]

 

Here is the finished mechanical result. I am pleased with the outcome although some adjustments are needed on the right grille. I did not do the electrics today as there is a show tomorrow, ran out of time, and I am now into Zaino. And quite frankly, I am still not sure where to get power for these lamps. I have to think about that.

In any case, they are on. My intent was to make the driving lights non-obtrusive on the lines of the C3. And to avoid Bubba work! I think I have succeeded: they are barely visible on the far side of the grille. And four holes drilled does not qualify in my definition of Bubba.

They are 55W high-intensity halogen lights so they should be very visible when turned on as driving lights. And that has been a primary concern of mine for some time. The low profile of the C3 makes it a prime candidate for collisions on both city streets and two-lane secondary highways as its oncoming profile is so small. These lamps should help in that respect. When I get them "live" I will post again with a pic.

Still need help with the circuitry!









[Modified by paul79, 8:53 PM 8/31/2002]


[Modified by paul79, 9:10 PM 8/31/2002]


[Modified by paul79, 9:32 PM 8/31/2002]

 

In looking at your wiring diagram it looks like the 79 is much much different than my 73. The 73 uses one of the contact on the horn relay as a positive junction post.

I want to say you can use the big orange wire, assuming it is big (10-12 guage but not sure you are familiar with wire "guages"). You could always try it and if you start having a fuse blow you can change it.

See, the driving lamps are power hogs and so you can't just hook it up to any old circuit. If you tried to connect it to, say, the 10 amp radio circuit then you would start blowing the radio fuses if you turned the radio and the driving lamps on at the same time.

So you need a power source that can handle a big load.

Absolute worst case, if you are unsure, you might just run it back to the battery.

Stay tuned... more to follow...

 

This is really no help but I replaced the driving lights in my '98 LS1 T/A with a couple of Hella "Off-Road" lights(actually made for 4x4's) that happened to be the exact same size. It was like friggin' daylight with those things! :eek:

 

I guess the question is: How do you hook up a single wire to this positive battery post?

 

I see you added the installed pics while I was typing... pretty :cool:

Now the reason for the 2 positive connections. This has to do with the relay.

Again, the relay allows a low power circuit to contol a high power circuit. Think of the relay as a switch, which it really is.

Look at the instruction sheet and look at the relay. At the top you have the circuit that connects to the battery and inside the relay box there is a line angled up (from left to right).

Now look at the bottom of the relay. The line does kinda a loop-de-loop. When power is applied to the the bottom circuit of the relay (the loop part) it causes the switch at the top to close (that angled line will become straight to connect the red wire on the left with the black wire on the right which powers both the lamps).

Now why did they do it that way.

Because the instructions want you to only be able to use the driving lamps while the headlights are on. The headlight circuit would be overloaded if you connected the driving lamps directly to it.

So, they toss in the relay. That green wire should connect to the headlights and then powers the relay (very low power requirement).

You said you wanted to be able to use the driving lamps anytime. The way around that is to connect the green wire to a power source that is positive all the time.

The suggestion to use an ACC circuit is that the driving lamps will operate only when the key is in the "on" position.

In a nutshell, you have 2 positive connections. One heavy duty circuit to actually power the driving lamps and a circuit that uses very little power to control the relay.

I hope this helps and I hope I didn't confuse you.

Good luck.

I'll be hanging around the forum tonight off and on so post if you have any questions. :cheers:

 

Probably the easiest thing to do is to take that picture down to a local parts store, and tell them you need to connect a wire to the postive terminal.

They should have a fancy device that you will pay way too much for that does the job just perfect enough to make you glad you spent all the money to get it. (By too much money I mean a few - several dollars for something that cost them 25 cents to make).

:cheers:


[Modified by gb4622, 7:44 PM 8/31/2002]

 

That is very instructive. Thanks again. I will not do the electrical side until Monday. I believe I have matters sorted out now. Tomorrow is a big show. Hope I do not lose points for being non-stock ;) .

 

I look forward to seeing them light up! But that will be in a couple of days...

 

just out of curiosity, I just checked with my insurance co. they said I can get a small reduction in the premium ($7.00) every 6 mos for installing them

 

I guess the obvious question is why? Perhaps the answer lies in my logic re visibility. I do not know.

 

Why the insurance is cheaper? it's a "safety device" if you aren't referring to my insurance blurb, never-mind

 

I have no knowledge of your insurance blurb...sorry :( .

 

Any additional thoughts on a power source that I can hook into? Running a wire back to the battery does seem unnecessary. The instructions assume the battery is under the hood I believe.




[Modified by paul79, 8:17 AM 9/1/2002]

 

You could hook it up to the starter. Just get a big o-ended connector and put it under the nut with the positive battery cable.

rgds Tomi

 

:yesnod:

 

that's what I would do.. or run a wire to the dash then the fuse panel, that wy I could install a disconnect switch