Headlight Relay

[5azzmonkey]

I just installed the headlight relay mod as I was losing ~ 2Volts to the lamp. It works great except now my headlamp warning light stays on. Anybody know the secret to bypassing the logic for the lamp or better yet how to wire it so it still functions?

other info: Original Low beam wire and ground now have no connection
High beam wire controls high/low

Mod I used:

http://i1214.photobucket.com/albums/cc486/5assmonkey/GSResources/HeadlightWiringDiagram.jpg

Thanks,
Dave

[posplayr]

I looked at the checkbox circuitry and it appears as if the checkbox really wants to drive the headlights itself. So you need to feed the relay ouput into the CHECKBOX as shown. It might be possible with some experimentation to work in parallel but it appears you would need a series diode which will drop 0.8V and must carry the toptal headlamp current.

The checkbox will detect the headlamp's low resistance path to ground through and keeps the checklight off. If that path goes opens the light will go on.

If the light is feed by a relay with the check lamp still connected the checklamp will probably always stay on.

Basically the Checkbox is detecting the current running through the headlamp with a small sampling resistor. No current the check light comes on.

[Steve]

It may not be the most-desireable option, but you could always remove the bulb from the panel.

.

[5azzmonkey]

I looked at the checkbox circuitry and it appears as if the checkbox really wants to drive the headlights itself. So you need to feed the relay ouput into the CHECKBOX as shown. It might be possible with some experimentation to work in parallel but it appears you would need a series diode which will drop 0.8V and must carry the toptal headlamp current.

The checkbox will detect the headlamp's low resistance path to ground through and keeps the checklight off. If that path goes opens the light will go on.

If the light is feed by a relay with the check lamp still connected the checklamp will probably always stay on.

Basically the Checkbox is detecting the current running through the headlamp with a small sampling resistor. No current the check light comes on.

Hi Posplayr,

Can you please take a look at this quick schematic and let me know if you think it will work?



-Dave

[5azzmonkey]

It may not be the most-desireable option, but you could always remove the bulb from the panel.

.

Hi Steve, Yeah I thought of that too but I was hoping to keep it functional.

-Dave

[posplayr]

I don't have a clear schematic that I can read, and I'm confused by your R/W wire. That is the stator wire that goes to the headlamp loop. So I'm having to guess a little about the actual conenctions the theory of operation in the manual is for the brake light.



As I said before the check box wants to drive the headlamps . Which means it is on the high side of the lamps. It is NOT just a function of current flow.

Relay ==> Check box ==> headlamp

[5azzmonkey]

I don't have a clear schematic that I can read, and I'm confused by your R/W wire. That is the stator wire that goes to the headlamp loop. So I'm having to guess a little about the actual conenctions the theory of operation in the manual is for the brake light.



As I said before the check box wants to drive the headlamps . Which means it is on the high side of the lamps. It is NOT just a function of current flow.

Relay ==> Check box ==> headlamp

I'll double check the color, clear schematics are hard to come by, when I get home.

I understand that the original check box is driving the headlamp (high side) but I want to rewire the control unit and have the lamp drive it (low side). This should limit the amount of wiring needed and only use the low or high side of the control current sensing. If I have time tonight I will try to make a better schematic (if I can read the original).

Thanks,
Dave

[posplayr]

I'll double check the color, clear schematics are hard to come by, when I get home.

I understand that the original check box is driving the headlamp (high side) but I want to rewire the control unit and have the lamp drive it (low side). This should limit the amount of wiring needed and only use the low or high side of the control current sensing. If I have time tonight I will try to make a better schematic (if I can read the original).

Thanks,
Dave

I got a better schematic. It is not clear how to use a relay to directly drive the headlamps and still provide functional check lights unless you completely change the check box.

Read the manual desciption of how the check light circuitry works. IT IS NOT A SIMPLE CURRENT SENSEwhich you can put either high side or low side. I was simplifying when I said that. It has to be high side.

The check box wants to pass the power source through itself to detect if there is current flowing through to the lamp.


It is really not clear how you could use a single relay for just Hi and Low and work with the check box and keep it functional to detect either lamp being out.

Good luck. I think I'll pass

[5azzmonkey]

I got a better schematic. It is not clear how to use a relay to directly drive the headlamps and still provide functional check lights unless you completely change the check box.

Read the manual desciption of how the check light circuitry works. IT IS NOT A SIMPLE CURRENT SENSEwhich you can put either high side or low side. I was simplifying when I said that. It has to be high side.

The check box wants to pass the power source through itself to detect if there is current flowing through to the lamp.


It is really not clear how you could use a single relay for just Hi and Low and work with the check box and keep it functional to detect either lamp being out.

Good luck. I think I'll pass

Hi Posplayr,

I did not realize there was a circuit description in the manual (my bad). I was solely using the wiring diagram and making assumptions and when you mentioned a current sense I was thinking of something along the lines of a hall effect sensor. I just took a look and it appears you are correct that it needs to be high sided.

Where is the check box located on the bike, is it on the frame somewhere or built into the instrument panel?

I'm thinking in the future I could make my own logic circuit and bypass the check box and control the indicator light myself. For now I may just pull the bulb

Thank you for taking your time to help me.

-Dave