I'm adding fog lights to my camaro. I found the electrical diagram in my hayne's repair manual but I don't understand a couple parts of it.



I understand the purpose of the relay, it's so that if you turn the headlight switch off it will turn the fog lamps off as well.

I don't understand why there is both a 16ga fusable link and a 20ga fusable link on the hot line for the lamps though. Seems like you would only need one fuse, and the wire would be the same size all the way?

Next, it shows the switch actually breaking the hot wire on the lamps. I'm surprised by this, figured there would be to much amperage running through this with the fog lights pulling power and it would burn up the switch?

And finally, I haven't gotten the actual switch in yet to inspect it, but why does it have both a Fog lamp indicator, and a panel light showing? Is the panel light something on the instrument panel that I might not have on my car? I know the fog lamp indicator is the little orange light on the switch itself. But the way it shows the wiring for the panel light confuses me as well. Hot goes into the fog lamp indicator, and the ground from it goes out and runs to ground. The ground side of the panel light runs to the same ground, and according to the diagram the hot side runs out to Interior Lights System... how does that work?

Granted my understand of electronics is very basic, would the hot not be running from the interior light system to the panel light? But at the same time if it did it would seem like it would always be lit based on this diagram.

Any advise on this would be appreciated. I'm sure I could wire it and make it work, but I wanted to do it correctly. I definitely plan to use the relay cause I could see myself forgetting to turn the fog lights off and getting a dead battery lol. I might just ignore the Panel light though if it's just some light in the instrument panel.

EDIT: Oh yeah forgot to ask, if anyone has specs on the relay could you post that as well please. Want to make sure I get a relay capable of handling the proper power load.

 

Not sure what type of file your pic is, but I can't see it.
The purpose of the relay is to provide the foglights with the proper amperage without having to run all that high power through the switch. Not sure why there would be 2 fuse links.

The best place to get power for foglights on the control side of the relay is same as factory, from the parking light circuit. That way the buzzer will warn you to shut your parking/head/fog lights off when you take the key out.

 

The image is a jpg... not sure why you would not be able to see it, any browser should be able to open a jpg lol. You can try looking directly at where it's hosted if you want http://www.zombiesweb.com/headlight.jpg

If you see the wiring diagram it's not showing the relay being used for the purpose you describe. The power line for the lights comes off the switch, not the relay. So the full amperage that the fog lights draw would have to run through the switch. That's one of the things that doesn't make sense to me.

 

Ya, that's not the way I remember the relay being wired last time I checked. You are correct, in this diagram, the full power runs through the foglight switch. The relay is upstream of the switch and only allows the power to flow through the circuit if the parking lamps are on.

If you are starting from scratch, I would run the relay in the more tradiational manner. Wire the control side of the relay off the parking lights to the switch, and have proper wiring from the relay provide the power to the foglights.

 

Here's the problem with Haynes manuals and their Reader's Digest wiring diagrams: GM changed that harness through the run. It was different in '85 and then changed again in '88.

Also remember that GM loved to make poor wiring choices and run all kinds of stuff through switches. On the early cars power for the foglights come through the foglight switch and the headlight switch. The relay was only used to turn the lights off with the running lights.

Having multiple inline fusable links is normal. Other things could be coming off of that same line and every time it splits and downsizes it needs a new fuse for the smaller gauge.

I agree with eseibel, you would do well to tap the power for the switched side of the relay from the headlight switch (so you don't leave the foglights on by accident), and run a fusable link from the starter solenoid or other proper junction to the power side of the relay.

 

Well, I got the actual switch in today, and picked up a fog lamp relay.

After looking at the switch it looks like it has a small light in the top that is on when the lamps are on, and a larger light in the middle that is on when the instrument panel lights is on.

So I'm guessing I can pull a hot wire off the instrument panel lights for that leg, ground the ground leg of course, and do like you guys suggested and put a low amperage hot wire through the switch and use that to switch the relay to pull power to the lamps through the relay instead of through the switch.

I just have to figure out which leg is which. Maybe I'll see if I can get a wiring harness for it rather than having to solder wires to the legs.