Motorcycle High beam stuck on - dual 5pin micro relays

M

Meeky1nz

New Member
Hi all,

Im new here and I am in no way electrically minded or trained but i am trying to learn. I have a Harley and I have equipped an Aftermarket headlight. I have put together a wire harness for it but it isn't working correctly and I can not figure out why. Ive been trouble shooting it for a week now which hasnt been the worst thing in the world as I feel as though I've learned some new things which is why i like to do the work on my bike myself but i am completely stumped now and need some assistance.
Please excuse my poorly drawn diagram below:
This is what I currently have. My high beam is stuck on which im thinking is because of the orange connecting wire between the 86 terminals: even when in low beam, 86 on relay2 will also be receiving power which activates the switch causing the high beam to turn on. But when I remove that connecting wire, I have Low beams when switch is in Low beam but when i switch to high beam all im getting is the back light. I checked the 86 terminal on relay2 and it is receiving power and i can hear the relay click but 87 isnt getting any power. I am assuming that if it was a wiring issue then the high beam wouldn't work at all?
I tried moving the blue low beam wire to 87a on relay 1 which worked but the light stayed on even after i had switched off my bike .


 
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Do you have a maintenance manual for your Harley ? If so they should
have electrical diagram in it you could follow.
 
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You need to find out what the switch is doing. According to your circuit, there is no power going to the switch, so there is nothing to power either relay. However you get something, so the circuit must be wrong or incomplete.
 
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Hi guys, thanks for the replies.
danadak said:
Do you have a maintenance manual for your Harley ? If so they should
have electrical diagram in it you could follow.
Click to expand...
This is a separate harness to the Harley as the headlight is quite powerful and so needs its own power, direct from the battery.


Diver300 said:
You need to find out what the switch is doing. According to your circuit, there is no power going to the switch, so there is nothing to power either relay. However you get something, so the circuit must be wrong or incomplete.
Click to expand...
I have tested both 86 terminals and they are receiving 12v of power from the bike. Also, If I move the Blue LB wire to run from relay one then the light works correctly - I can switch from low to high which shows there is power getting to the relay, however, the LB stays on even when the bike is turned off as it is receiving power directly from the battery.

If I remove the bridge between the 86's, the LB works but the HB doesn't. 86 on relay 2 is getting power and I can hear the click of the relay but the 87 terminal that the HB is on, doesn't seem to want to work. Ive swapped out multiple relays and all give me the same result.

Could It be something like a bad wire? I dont know if that happens or not?
 
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I'm confused why pin 86 of both relays are connected together. Relay #2 appears to be HI/LOW select, with Relay #1 being power on/off to the headlight.
I think that connection is wrong. And what's in the switch that has a ground connection? Should only be +12 in, to output contacts, so it is silicon transistors and other stuff inside that? I assume each relay has it's own Lenz's anti-kick diode?
Or is that inside the switch?
Like others, what's in the switch?
 
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Hi iggnator,

The switch is where the harness connects to the Harley. I don't actually know what that part is made of.
The bridge between to the to 86pins also confuses me. I actually bought a £200 harness with this exact setup and it works perfectly. I am trying to replicate this for a friend at a fraction of the cost but it has not worked how i had hoped.

I just cant work out why on my circuit, that on relay 2, pin 86 is receiving power but the switch is not turning on 87.

Sorry i know i'm not giving much to go by here. I do appreciate the input.

I have been suggested to possibly trying a diode on the bridge to only allow the current to go one way. Still don't understand how the £200 harness does it without one though
 
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Hi Diver,

Below are all the readings.

No Bridge
Relay 1
Switch on LBSwitch on HB
3011.7212.04
8711.680.02
8611.620.01
Relay 2
Switch on LBSwitch on HB
3011.650.02
870.150.02
87a11.610.03
860.0811.81
Backlight11.8211.82
Bridge
Relay 1
Switch on LBSwitch on HB
3011.4311.38
8711.3811.32
8611.2911.24
Relay 2
Switch on LBSwitch on HB
3011.3411.29
8711.311.25
87a10.7410.7
8611.2411.22
Backlight11.8211.82


So im guessing the bridge is there because relay 1 86 still needs to get power when switch is flick to 86 relay 2 so that relay1, 87 gets power and therefore is able to power relay 2 but then with the bridge everything is being powered no matter the switch position.
 
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Can you temporarily disconnect the pin 86 short, and let the switch independently control those relays. I can only see that relay #2's only function is to select high or low beam only. When it is not powered low beam power is passed through from the power on relay#1.
 
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I agree with iggnator's post #11 that the relays need to work independently.
Do the following.
Remove the red wire from relay 1 pin 87 and connect it to relay 1 pin 30. (So the relay common contacts (Pin 30) are both permanently connected to +12 volts.)
Remove the blue wire ftom relay 2 pin 87a (Normally closed contact.) and connect it to relay 1 pin 87. (Normally open contact)
The orange wire between relay 1 pin 86 and relay 2 pin 86 needs to be removed.

Les.
 
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When the relays are linked, both operate in either switch position. What I don't understand is why connection 87A is at a high voltage in that condition. It could be that you have ground and high swapped at the headlight or if it's an LED headlight that could be perfectly normal.

I think that Les has the right idea. You need a high beam relay and a low beam relay. It is currently wired as a headlight on/off relay and a high/low relay.
 
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Woah! Look at the diagram, how is +12 coming from the switch to turn on either relay. Only a ground connection is shown.
The +12 connection to the switch is missing from the diagram, and the ground connection is probably the mistake in the drawing.
 
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Normally it looks like this except missing chassis grounds for bulbs and battery. The switch normally does not need gnd unless needed for a backlight.

#86 is the coil + to enable Vbat+ from #30 to 87 in the lower Relay. Then the upper has two output positions from 30 to either 87A or 87.



Thus just remove one wire which makes the hi/lo fail by forcing it to stay on high when Power ON

 
Last edited:
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Re post #14. From the table in post #9 there must be a +12 feed to the switch. I think this switch is an ORIGINAL switch on the bike and the TS is just guessing as to how it is wired. We have not been told if this switch is the original one or an added switch.
From the part of the table without the link between pin 86 of the 2 relays in post #14 the low beam switch position energises only relay 1.
In the high beam position ir energises only relay 2.
In the diagram in post #1 (But with the link removed.) the contacts on the relays are are connected on the assumption that the orange wire from the switch is head lights ON/OFF and that this has +12 volts on it in both low beam and high beam positions.
It also assumes that the green wire from the switch only has +12 volts on it in the high beam position so this would rout the output from relay 1 contact 87 to the low beam when there was NO 12 volts on the green wire. When the was there was +12 volts on the green wire relay 2 would be activated switcing it's 12 volt output from it's contact 87a (Which supplies the low beam.) to it's contact 87 which supplies the high beam.
I think the TS just assumed the outputs ftom the switch without working out the truth table for the switch when drawing the diagram in post #1.

Les.
 
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Hi All,

I really appreciate all the help.

I've ended up going with the suggestion of using a relay for each LB and HB which has worked.

Relay 1
30 - Power from Battery and looping over to relay 2 30
87 - to headlight LB
86 - to Harley LB switch
85 - Ground

Relay 2
30 - Power from relay 1
87 - to headlight HB
86 - to Harley HB switch
85 - Ground

Using this configuration i guess i could also use 4pin relays instead.

I still have no clue as to how the bought harness is working but all I needed was a working harness so I'm happy.

Thank you all.
 
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It is possible that some models / years used a different switch arrangement that works with one relay to turn on and one to select high/low.

If the switch has both outputs on in the "high" position, you first scheme (without the link) would have worked.
 
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