H4 Headlight upgrade ..., stupid question ... Options

[blitZ]

Call me foolish but I have put H4's on both my old 924 and my current 944, never installed a relay and have never in 5+ years had an issue. (IMG:style_emoticons/default/confused24.gif)

It all depends on the bulbs you are using. I upgraded to the Hella H4s and stuck with the stock wattage 60/55, so I don't need to run them straight from the battery. You only need relays if you go with the 100w high beams. The standard H4 is plenty bright for my purposes.

[SGB]

Yep, Les is right. Its not the H-4s, it's the increased wattage that can be used if one chooses...

[r_towle]

For H4 headlights did you get some sort of housing and then the little halogen bulbs, or is it a sealed beam light?

If its a housing, is there a specific part number or must we go to Pelican for the parts??? I mean can I go to NAPA and get the right sized housing...no clue about this...

Also..where are you getting the battery power from? Did you run new lines (four) from the battery, or did you run one up to the front trunk? Or, are you getting it from the main feed at the fuse box???

RIch

[blitZ]

Mine are the housing with replaceable bulbs. Hella has a nice glass one, there are some cheap plastic ones on ebay, which I have heard suck.

Hella H4

If you go with the 100w bulbs you'll need to get power straight from the battery as the fuse panel can't handle it. The original power lead for the headlights, becomes the switch for the relay.

[andys]

Here's a pretty good read on the issues, and diagrams on how to employ relays.

http://www.danielsternlighting.com/tech/relays/relays.html

Andys

[effutuo101]

my thought on this is to use the current wireing to trigger relays to power the lights. So, when you turn the lights on, the low beam wires turn on the relay (you can use one for both or one for each side). Same with the high beams. You can buy a fuse block from FLAPS and run the necessary power to the fuse block. Run from the fuse block to each relay.

Low beam R wire to Relay applied power
Low beam L wire to Relay applied power
High beam R wire to Relay applied power
High beam L wire to Relay applied power

Battery or Stock fuse block + to fuse block
Fused connection to relay LR,LL,HR,HL constant power
Ground each relay

This would keep the stock switch and High/low relay in play and not require a huge amount of rewire.
If you lift out the tank, you can run the new power along the stock wireing loom and keep it low profile. Mounting the fuse block on the headlight bucket (below the tire cover) makes for easy access.
A GT headlight pop up kit and you can lose another 5 lbs off the front of the car.
Thoughts?

[r_towle]

Mine are the housing with replaceable bulbs. Hella has a nice glass one, there are some cheap plastic ones on ebay, which I have heard suck.

Hella H4

If you go with the 100w bulbs you'll need to get power straight from the battery as the fuse panel can't handle it. The original power lead for the headlights, becomes the switch for the relay.

What size wire did you use?
Did you run four new wires???
I understand the relay wiring using the stock setup...got that.
Rich

[Rav914]

The original power lead for the headlights, becomes the switch for the relay.

This is an important point; one that took me a while to figure out (I'm such a rock when it comes to E).

So, if I have this correct, the original power lead goes to terminal 86 on the additional relays?

[sixnotfour]

yup

[Rav914]

Sweet. Thanks Jeff.

[blitZ]

What size wire did you use?
Did you run four new wires???
I understand the relay wiring using the stock setup...got that.
Rich

I didn't use the 100w H4s, I used the 65w, so I just used the stock wiring. There is no need for relays or extra wiring.

However, if you use the 100w bulbs, it seems one wire from the battery to handle 200w would require 10ga wiring.

[Rav914]

I'm installing two wires at 12ga. each.

[andys]

Here's a test that demonstrates how relays can help relieve voltage drop. Different situation I know, but the info is good.

http://www.madelectrical.com/electricaltec...eadlights.shtml

Andys

[r_towle]

I'm installing two wires at 12ga. each.

Great, confuse me now..

So are you using the stock wiring for the low beams and the new wires for the high beams....hmmm

Rich

[Rav914]

I had some extra time today so I wanted to tackle this problem. Here's what I did:

Since my low beams are 55W I decided to stay with stock wiring and not touch a thing. I'll run only additional relays and wiring for the 100W high beams. I bought and attached an aftermarket CB Panel in the engine compartment. You see three wires. All 12ga. Left to right is High Beam (HB) left, HB right, and a spare. Should I need to run something from the battery in the future it's nice to have a spare feed already hooked up. The wires go through the bulkhead and under the passenger seat. The third wire is capped off under the seat.

I then ran the wires up the tunnel with the main harness, over the top of the main CB panel and up out to the front trunk. At this point I changed the color of the HB right wire to white.

I made a small aluminum bracket to hold the relay to the headlight motor cover. I pulled 56a from the headlight bracket, fed it back through the opening to the bucket, and attached it to terminal 86. The original power wire (56a) that would turn on the highbeams now powers the relay. The power feed from the battery went to terminal 30. I made a wire to run from terminal 87 to go to the headlamp. And another, the green one, to go to ground from terminal 85.

I showed only the left side but the right is set up exactly the same.

I like using the stock wiring in this way. As mentioned previously in this thread it alleviates a lot of extra wiring and work. Also I have two CB's prior to the headlight. A good safety margin. I haven't tried it out yet since I need the battery to remain out of the car for another repair.

Thanks for the help all! (IMG:style_emoticons/default/beer3.gif)