Getting around Lighting problems

[raymr]

During my trouble shooting I found that my dad had rigged the wiring in the headlight bucket to bypass something. I figured out what, since the control switch was bad, and now the relay is not delivering voltage to the headlight wire. I'm bringing everything back to the stock configuration but I may want to stick an extra relay in the headlight to take the current load off the switch.

What are you doing to make sure the lights stay on?

[Bob_Roller]

I think one thing you can do to take a bit of load off of the headlight switch, is to put a relay in the circuit .

With a relay, you are only putting whatever it takes to operate the relay power wise, which is much lower than the 5 or so amps the headlight takes to operate .

Clean and tighten up the electrical connections in the wire harness as well .

[raymr]

Thanks. Once I'm done with the front fork rebuild, I'll look at adding the single relay in the headlight housing. It looks like the simplest method, just needing the switched headlight wire from the OEM headlight relay extended to the headlight housing. Then the switch will only handle power for the high beam relay. Lighting otherwise defaults to low beam.

[steven m]

I put in a relay kit on my 83 that runs all the power to the headlamp directly from the battery so the handlebar switches only handle low power signals.  Not only does this provide full voltage to the headlamp, very important, but also takes the load off our now old wiring and switches.  It all fits inside the headlamp shell so it looks and works as stock.  Members of the forum, with more knowledge and confidence in electrical wiring than I have, have made their own setups for just a few dollars.  Haven't has any trouble with it and have nice white light all the time.

Steve

[montmil]

Ray, You might wish to reconsider mounting the headlight relay in the headlamp shell as that's a lengthy wire run from the shell back to the battery. Note the existing relays on the bike are near the battery. You'll want to use a 12ga wire from the battery to the relay.

Here's a very good article about BMW relays, their workings & differences, relay substitutions and installations.

http://www.airheads.org/content/view/159/98/

Monte

[raymr]

The 3rd diagram is the one I'm considering. Regarding relocating relays, I don't want to veer too far from the stock setup. I can run separate 12 ga from the OEM relay to the headlight shell, if it makes a noticeable difference.  

Ray, You might wish to reconsider mounting the headlight relay in the headlamp shell as that's a lengthy wire run from the shell back to the battery. Note the existing relays on the bike are near the battery. You'll want to use a 12ga wire from the battery to the relay.

Here's a very good article about BMW relays, their workings & differences, relay substitutions and installations.

http://www.airheads.org/content/view/159/98/

Monte
 

[Justin B.]

I see nothing wrong with mounting the relay in the bucket as long as the wire feeding it is of proper weight and fused close to the battery.  You can then power the relay with the wires that currently attach to the headlight.  If you use a SPDT relay then you can energize it with the "high-beam" wire and attach the low beam bulb terminal to the NC (normally closed) terminal/contact and the NO (normally open) terminal/contact to the high-beam bulb terminal.

This will feed solid 12v to both low and high beam, save an expensive handlebar switch, and give you brighter lights to boot.

[raymr]

The local Radio Shack only had SPST relays. Maybe I'll check Advance Auto, but it seems I have to buy more and more stuff online. And shipping for a $5 item, yadda yadda....

I see nothing wrong with mounting the relay in the bucket as long as the wire feeding it is of proper weight and fused close to the battery.  You can then power the relay with the wires that currently attach to the headlight.  If you use a SPDT relay then you can energize it with the "high-beam" wire and attach the low beam bulb terminal to the NC (normally closed) terminal/contact and the NO (normally open) terminal/contact to the high-beam bulb terminal.

This will feed solid 12v to both low and high beam, save an expensive handlebar switch, and give you brighter lights to boot.

[Justin B.]

Here's one on fleabay for a little over $4/shipped:

http://www.ebay.com/itm/12V-40A-RELAY-5-WIRE-SOCKET-HARNESS-SPDT-/280579171636?pt=LH_DefaultDomain_0&hash=item4153d26534

[raymr]

Thanks Justin. I didn't see that one but I got a 'waterproof' one with connector on Amazon, $8 shipped.

The stock headlight wires from the relay are 1mm or ~18ga. Then they change to 16ga just to the handlebar switch! I plan to solder in heavier wires from battery<-->relay<-->headlamp shell as part of the upgrade.
 

Here's one on fleabay for a little over $4/shipped:

http://www.ebay.com/itm/12V-40A-RELAY-5-WIRE-SOCKET-HARNESS-SPDT-/280579171636?pt=LH_DefaultDomain_0&hash=item4153d26534