Topic: Read every H4 headlight relay post and still very confused :(

[robdrobd]

I understand the concept, but the process is blowing my mind. Right now I have all of my wiring hooked up correctly sans the blue, white and green headlight wires. I have a 1975 cb750 and want to put in an "economical" relay for my new H4 headlight. Here are my questions.

1) will my left hand control still control hi/lo beams after relay is installed?
2) will I use the blue and white wires coming from the harness if I install a relay?
3) Is the old headlight fuse rendered useless after the relay?
4) if my headlight power comes straight from the battery, how is it not on even when the bike is parked overnight?
5) Do I have to install an aftermarket on/off switch or something to solve #4?

Sorry, but the wiring diagrams for relays seem ok on the forum, but what happens to all of the old fuses, wiring, switches, etc. Are they all just useless after the relay?

Is there a step by step FAQ for this process somewhere? So simple a nimrod like myself could figure it out?

PS- Everything I read says this doesn't take long at all, but its blowing my mind. If anyone in CNY wants to come do this for me I will pay you the local shop rate (a six pack and any of my spare parts you want)

[Don R]

1 use two relays one low, one high, 2 yes, 3 no, 4 the relays are remote switches that turn it off using the original switch, 5 no see 4.

[rboe]

You should install a fuse on the hot coming off the battery.

You current switch is used to control the light via the relay (if wired correctly).

The other questions I can't answer without a schematic of what you wired. If the light still does not work then chances are very good you have a bad ground somewhere. You'll need to get a meter and trace it out yourself.

[vames]

do you understand what a relay is? think of it this way: it is a switch that is controled not by your finger, but by a tiny bit of electricy. you want that tiny bit of electricity to be what previously ran the headlight (white and blue) to flip the switch for a fused hot line coming straight for the battery. 

with all that in mind:

1) Your left hand control will still control high and low, but it will now only have a little bit of electricity (to flip the bigger switch) running through its fragile contacts. NOTE: HIGH AND LOW WILL EACH NEED THEIR OWN RELAY, SO YOU NEED TWO RELAYS TOTAL.

2) Yes -- the blue and white will provide the little bit of electricity to their respective relays to flip the switch for the big wire to provide electricity to the headlight.

3) Yes -- the old headlight fuse is now only "protecting" the relays. You'll need to leave it in there, but you'll need to install a proper fuse on the "straight to the battery" wire that's carrying the electricity through the relays and into the headlight.

4) It's not on when the bike is not on because the electricity to flip the relay's switch will not be on.

5) NO

Think about it this way:

Now: Flip headlight switch, electricity runs through it to the headlight and it lights up.

After: Flip headlight switch, electricity runs through it to the relay, flips the relay switch. With relay switch in ON position, electricity runs straight from the battery to the headlight.

[robdrobd]

Hmmm, so if all of the original wires and fuse are still used, where does the relay splice in?

[robdrobd]

I finally figured it out, but to buy all the tools, wires, relays,tape, etc. the total came to about $50. The plug and play Eastern Beaver kit was $54. No brainer.

[bollingball]

I finally figured it out, but to buy all the tools, wires, relays,tape, etc. the total came to about $50. The plug and play Eastern Beaver kit was $54. No brainer.

HondaMans kit is $48 and it is truly plug&play does not get any easier.
http://sohc4shop.com/catalog/product_info.php?cPath=23&products_id=46

Ken