Headlight Relays

I will do a Search, but I have a specific question and I know most of you are at work gazing at the BBS screen. Friday, you know.

Where do you mount the relays?

I'm tempted to penetrate the wheel well with a fastener or two, and mount the relays below the front of the fuse box, above and behind the battery. I just don't like doing any cutting on this car, and don't want to create a leak from the wheel well into the trunk

By the way, for those interested in this important upgrade, the wiring part will be truly simple. Warren's been so nice giving me advice that I can probably help someone else, particularly late SCs. Again, the wiring changes are VERY minor. The tough part is deciding where to mount them.

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'83 SC

I have been researching all of this, but I am still unclear on where the parts go. I am getting H4's, and want to put in the relays even for the lower wattage bulbs. tHe relays are cheap, and I would rather be safe than sorry. I just don't get the placement/ wiring stuff. Maybe someone has a roadmap or a more detailed description of this? I woudl hate to have to pay someone to do this, it sounds like it is rather simple and a great learning tool.

Any help would be appreciated.

Magilla Gorilla

Hey Big-S,
I've got H4s on my SC, no relays (yet), but I seldom drive at night. I'd be interested in a schematic and pictures if you don't mind.
Warren - I know you are a big fan of this better idea yourself. Could you detail or schematic the independent 4-light system you use?
Also, I have some aftermarket driving lights that I wired into the stock fog light system (replacing the fog lights). Will that aging system handle 100W?
Thank you all for participating on this great board.

RarlyL8, Warren or someone who knows elecrtrical math can answer yoru question better, but here's my take: You fogs are already relayed, and I suspect the system is fufficient for 100 w driving lamps. My guess.

Those of you above, I think I can describe a very easy installation, as long as you're talking about a late SC or similar. Actually, others would be just as easy. I might even find a way to provide pictures, but I need to complete my installation before I can be of maximum help to you. The wiring itself is very, very easy. It's the location of the relays that I'm agonizing over.

Someone tell us where to mount the relays. My search has not turned up much.

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'83 SC

I purchased the OEm style Bosch round relay socket and relay. It fit (albeit with difficulty) in the fuse panel in one of the open round holes. Works GREAT! Looks OEM. No holes to cut no extra wires. I simply took the lead off the fuse from the lights and put it on the relay. The wire from the switch (the other side of the fuse) turns the relay on. SOldered these up. Made the hot wire from the battery to the relay connect to one of the battery connections on the fuse panel. Getting the hot from the ignition side fuse panel may not be a good idea. I didn't count wattage and wire size and all that.

I could send pics if anyone is interested.
P.s. I think I got the relay and socket from Pelican.

Nick

I would love pics!
Magilla5592@hotmail.com
Thanks!

Hi All,
Here is a simple schematic for wiring you lights and relay.




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Tom Sharpes
90 C2 Targa http://members.rennlist.com/5150targa

[This message has been edited by team5150 (edited 01-13-2001).]

[This message has been edited by team5150 (edited 01-13-2001).]

Hey Tom,

Shouldn't one of those diagrams be for the Yellow wire to the fuse block & the low beams?

And, yes, Super ... that/those diagram is just what I was talking about doing at the fuse block! As for the location, are there any 'spare' (vacant locations) spots on your relay 'strip'???

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Warren Hall
1973 911S Targa

There is one vacant, round relay location on my panel. Nick's installation would surely be nice, but I only have one vacant location. And the relays I have are square.

I'm trying to think of a place I can attach a small aluminum sheet with the relays attached, without drilling. I'll drill between the trunk and wheel well if I have to, but I don't want to.

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'83 SC

I don't know if this will help, I had to use a Bosh relay the other day for my Blaupunkt amp that would not turn off.I backed out the screws that hold the little round metal clip that holds the carpet in place, just behind the right front wheel this gave me a secure and safe place to screw the metal clip to, without drilling a new hole, it was also a good place as far as clearance so the wires would not come in contact with the wall. I hope this helps.
GB83SC

Super,

Well, if the vacant relay is at the end, could your aluminum be mounted at/over that round hole, with both relays right next to each other -- no gap? I assume you will need to make 'z-shaped' end bends to raise the relays up about 3/4" or so. Sound workable? Or, maybe the aluminum shape needs to be an elongated '?' turned on its' side?

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Warren Hall
1973 911S Targa

Well this has been an interesting subject cause I have also been wondering how to wire up the relays. I do have one question though. Is there a separate fuse for the high beam and the low beam circuit?? Thanx in advance I printed out that wiring diagram so I will have it for reference.

Hmm seems I may have a stupid question I have not yet purchased mt relays yet. How do you know which prong on the relay to use are they marked in any way?? What type of relay would I need? How many prongs are on the relay? Are they rated for different amounts of voltage?? If so what voltage would I need? wow my one question turned into 5.. either post here or email me directly thanx for all the help guys this site is nothing short of AWESOME!!! Just like our cars!!

Thanks folks. I'm still not sure what I'll do, but you've given me some ideas. the relays I have are pretty standard, square, Bosch relays I got in a local VW repair shop. they are prepared to deliver power to two circuits, but I may only use one. they typically have a schematic printed on the side, so yes, you can tell which is power in, which is ground, which is signal and which two are output power.

My car has four separate fuses, one for each filament (two highs, two lows). But these are connected at the back of the fuse block, so it makes sense to feel them a single power supply if that's more convenient, like in the nice schematic above.

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'83 SC

I leave you guys alone for a little bit and you kick my important topic off Page 1. Well, fine.

I made the installation today. The wiring harness that came with these relays is 14 gauge wire, so when I add the 100 watt highs, they will be marginal. I may take power from the second 'pole' on the highbeam relay to relieve the 14 gauge wire from this amount of current. Warren tells me the factory wiring uses a common ground for the highbeams, and that it may also be too small. We'll see.

Anyway, I drilled three holes in a 4" x 4" sheet of aluminum, attached the two relays and attached the sheet under the fron lower corner of the fuse box. The fuse box attaching screw there was missing the little plastic spacer anyway, so I made a thinner rubber washer so, with the washer and aluminum plate, is spaced properly. Power comes right off the battery and that's where the ground goes too.

Anyone is welcome to e-mail me if they think I can be of assistance.

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'83 SC