Headlight relay question

bountyhunter wrote:

There should be a main 12V line coming off the ignition switch going to a 20 or 25A fuse. The power for the ignition should tap off that line somewhere, you can put the relay right after that point so it cuts off everything except the ignition at starting crank.

OK, I found the right wire leading to the headlight circuits and installed the relay using the wire from the clutch starter lockout switch to the starter relay to control the headlight relay. When I push the starter button, the headlight turns off as planned, but the starter does not turn over. I hear one relay - I'm guessing the headlight relay, not the starter relay.

I started with a 40 amp relay for the headlight, and when that didn't work, I tried a 10 amp mini-relay with the same result. I've tried wiring the relay two different ways, first with the 87 post open, and then with 87 going to the starter solenoid (like Bill Willcox's diagram for his KZ650-B1). The result was the same with both.

Any thoughts? Is it too much to have two relays on the starter button circuit?

The starter button can drive a ton of relays. If the starter is not working, it sounds like the relay to "open" the light circuit may also be opening the starter relay power line as well.

I would use the relay to interrupt the ground from the headlight, that way you kill high and low beams, but you have to use the ground wire right near the head light or you will also be shutting off other things depending on where you split the ground. :ohmy:

This is assuming the wiring is in stock form;

1. Take one of the leads from the starter switch and cut it, attach one side to 85 and the other to 86 on the relay.

2. Take the ground wire coming off of the headlamp connector (before any other grounds connect into it) cut it. Connect one side to 30 and the other to 87a.

Note: Try to avoid adding wire to the headlight ground, extend the leads from the starter button if neccesary. This is becuase the starter button circuit is just a signal, where as the headlight circuit is carrying the full load of the headlamp. And make sure that any wire added is of the same guage of (or larger than) the existing wire.

JakeB wrote:

I would use the relay to interrupt the ground from the headlight, that way you kill high and low beams, but you have to use the ground wire right near the head light or you will also be shutting off other things depending on where you split the ground. :ohmy:

This is assuming the wiring is in stock form;

1. Take one of the leads from the starter switch and cut it, attach one side to 85 and the other to 86 on the relay.

2. Take the ground wire coming off of the headlamp connector (before any other grounds connect into it) cut it. Connect one side to 30 and the other to 87a.

Note: Try to avoid adding wire to the headlight ground, extend the leads from the starter button if neccesary. This is becuase the starter button circuit is just a signal, where as the headlight circuit is carrying the full load of the headlamp. And make sure that any wire added is of the same guage of (or larger than) the existing wire.

Wish I'd thought of that. I think the place I cut into the headlight wire works because it cuts the power to the reserve lighting unit, so I don't think that's the problem. Good point about adding wire to the leads to the starter button rather than the headlight ground - that hadn't occurred to me.

bountyhunter wrote:

The starter button can drive a ton of relays. If the starter is not working, it sounds like the relay to "open" the light circuit may also be opening the starter relay power line as well.

I tried disconnecting the leads to the relay except for 85 and 86, the ones that power the coil. Those I left connected to the black wire going to the starter solenoid from the starter button. Results were the same - the headlight relay clicks but the starter relay doesn't and the starter doesn't engage. I've tried three different relays - two 40 amp ones and the 10 amp with the same result. If I take the headlight relay out altogether, the starter relay works. I'm not sure what to try next. I could wire poles 85 and 86 into the ground wire coming out of the starter relay. I don't see how that would make any difference but I can't think of anything else.

KYKZ1100, when you press on the Starter Button, do you get a voltage (use a meter set to DC Voltage) at the Starter Relay (Solenoid) control wire input end?

IMHO:

1A) If no, then you have a wiring fault. Retrace your wire and be prepared to fix or replace the wire...

and or,

1B) Check that voltage actually comes out of the mod relay when you press that Starter Button! If not, be prepared to recheck your mod relay wiring and retrace/test each relay wire.

2) If yes, then you have no ground at your Starter Relay (Solenoid). Be prepared to repair or replace the ground wire or to select a better ground point (Battery - ).

Best of success,
Bill

PS
Sorry, but I don't know anything about this Head Light sensor circuit. My mod. was designed for my model (KZ650-B1) which appears to have a simpler circuit and has worked reliably for me to date for that intended model.
Bill

bill_wilcox100 wrote:

KYKZ1100, when you press on the Starter Button, do you get a voltage (use a meter set to DC Voltage) at the Starter Relay (Solenoid) control wire input end?

IMHO:

1A) If no, then you have a wiring fault. Retrace your wire and be prepared to fix or replace the wire...

and or,

1B) Check that voltage actually comes out of the mod relay when you press that Starter Button! If not, be prepared to recheck your mod relay wiring and retrace/test each relay wire.

2) If yes, then you have no ground at your Starter Relay (Solenoid). Be prepared to repair or replace the ground wire or to select a better ground point (Battery - ).

Best of success,
Bill

Bill,

I have 10.8-11.0 volts at the end of the Starter Relay control wire coming from the starter switch, and when I connect that to terminal 86 of the mod relay and check the voltage at terminal 85 it's also 10.8-11.0 volts, so there's little if any voltage drop across the relay. If I just hook the ends of the Starter Relay control wire that I cut back together, the starter works. This is without terminals 87, 87a or 30 connected to anything. I also connected the ground wire from the starter relay directly to the negative terminal of the battery with the same result.

Then, instead of inserting the relay into the starter relay control wire, I inserted it into the ground wire coming out of the starter relay - same result. Not sure what to try next.

At the moment you have ~11 Vdc into the Starter Relay (Solenoid) what is the voltage out of your battery? If there is a big difference you could have a high resistance contact somewhere between the Battery + and or - and your Starter Relay. Be prepared to clean, repair or replace the high resistance item.

Best of success,
Bill

Another reason why I'm not a fan of the relay/coil mod... :whistle: for @ 10.8-11.0 volts, relay/switch/mods are only bypassing the real problem. :S

Via OHMS law:
P / E = I

Translation:
Wattage / Voltage = Amperage

Headlight low beam: 55 watts / 12 = 8.333 amps
Tail light running: 23 watts / 12 = 1.916 amps
Total = 10.12 amps

If you must go this route, Go with a 15 or 20 amp relay for head/tail/running lights and you'll be fine...

OMR

bill_wilcox100 wrote:

At the moment you have ~11 Vdc into the Starter Relay (Solenoid) what is the voltage out of your battery? If there is a big difference you could have a high resistance contact somewhere between the Battery + and or - and your Starter Relay. Be prepared to clean, repair or replace the high resistance item.

Best of success,
Bill

Bill,
The battery voltage was 12.15v at the time, so there is a drop but I don't think that's the problem. I've read elsewhere that the Bosch-style relays need 8 volts to switch. I'm not sure what my starter relay needs. The only thing the FSM says is that the resistance across the 2-pin connector (to the starter switch) should be "a few ohms." I measured 3.8 ohms across those leads. I also hooked up a trickle charger to the battery and while it was hooked up I measured 12.75v at the wire coming from the starter switch. With the charger hooked up, the mod relay clicks but the starter relay still doesn't.

OMR wrote:

Another reason why I'm not a fan of the relay/coil mod... for @ 10.8-11.0 volts, relay/switch/mods are only bypassing the real problem.

Via OHMS law:
P / E = I

Translation:
Wattage / Voltage = Amperage

Headlight low beam: 55 watts / 12 = 8.333 amps
Tail light running: 23 watts / 12 = 1.916 amps
Total = 10.12 amps

If you must go this route, Go with a 15 or 20 amp relay for head/tail/running lights and you'll be fine...

OMR

OMR, I agree with you about the coil mod. Although I've done that I plan to go back and fix the problem of the voltage drop (I was only getting 8 volts at the coil). For this headlight relay, though, I don't think the voltage drop is the problem. Also, I am using a 10 amp mini relay rather than the 40 amp, although I've tried two new 40 amp relays also with the same result.

I've replaced the front turn signals and brake light bulbs with LEDs that are supposed to be 25ma on the low setting (when not flashing and brake lights are not on). I've also replaced 4 of the instrument lights and all the warning lights with LEDs. I'm just tying to eliminate the 4.6 amps going to the headlight while the starter is cranking. I would just go the switch route but I'm getting to the age where I sometimes forget things, and I don't want to have to remember to turn the headlight on. I'm also a little stubborn and want to figure out why this thing isn't working the way the laws of physics say it should.