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mark75b
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Hi I would like to install a 100/90W headlight harness that I got from victoria parts but there is one plug with 3 wires that I don't know what to do with.Has anyone done one.
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Scott_Hower
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I've added Cibie H4s to my B. I have custom made harnesses using bits from British Wiring.
A standard 12V Bosch style relay generally has 4 connections (some have 5):
- a switch or coil lead (from the headlight switch, controls the relay coil)
- a ground (ground for the relay coil)
- a load lead in (high current from the source)
- a load lead out (high current to the headlight)
You should have 4 leads, not three.
Ok, I just had a look at the wiring harness that VickyBrit sells. The headlight plugs have three leads: low beam, high beam and ground. You should be able to just plug them in to your headlights and then connect the grounds to the chassis.
The relay end of the harness will have four or five leads, three of which you need to connect somewhere: a high current +12V feed, a low current switched +12V feed, and a ground. The feeds to each beam should already be connected to the headlight plugs. The high current feed can be connected to the lug on the starter solenoid (which gets power from either the battery or the alternator). The low current feed will use the blue/red and blue/white wiring from the headlight switch (low beam on one relay, high beam on the other relay). Dont forget to connect the ground. You might want to use a fuse somewhere in the circuit.*
A relay is nothing more that a remote controlled switch used to handle high current loads. You use the existing headligh switch feed to energize/deenergize the coil (the remote switch) which controls the high current circuit.
Hope that helps.
* Some folk's won't fuse headlights, but I wired each beam independantly and also have 10watt city lights inside my headlight housings. The odds of losing all of them are pretty slim.
A standard 12V Bosch style relay generally has 4 connections (some have 5):
- a switch or coil lead (from the headlight switch, controls the relay coil)
- a ground (ground for the relay coil)
- a load lead in (high current from the source)
- a load lead out (high current to the headlight)
You should have 4 leads, not three.
Ok, I just had a look at the wiring harness that VickyBrit sells. The headlight plugs have three leads: low beam, high beam and ground. You should be able to just plug them in to your headlights and then connect the grounds to the chassis.
The relay end of the harness will have four or five leads, three of which you need to connect somewhere: a high current +12V feed, a low current switched +12V feed, and a ground. The feeds to each beam should already be connected to the headlight plugs. The high current feed can be connected to the lug on the starter solenoid (which gets power from either the battery or the alternator). The low current feed will use the blue/red and blue/white wiring from the headlight switch (low beam on one relay, high beam on the other relay). Dont forget to connect the ground. You might want to use a fuse somewhere in the circuit.*
A relay is nothing more that a remote controlled switch used to handle high current loads. You use the existing headligh switch feed to energize/deenergize the coil (the remote switch) which controls the high current circuit.
Hope that helps.
* Some folk's won't fuse headlights, but I wired each beam independantly and also have 10watt city lights inside my headlight housings. The odds of losing all of them are pretty slim.
OP
mark75b
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Hi Scott
Here is what I have Relay 1,two yellow, two blue with white line, one all white ,one red wires.
Relay 2, 2 solid blue, one blue with white line, one brown, one red with white line.
Headlights get one blue, one yellow and one black ground each.
The red and red with white line go to battery or starter.
The last plug has one brown,one white,one blue with white line.
I know 1 must be for low 1 for high and the other I don't know or where I hook any of them in.
Here is what I have Relay 1,two yellow, two blue with white line, one all white ,one red wires.
Relay 2, 2 solid blue, one blue with white line, one brown, one red with white line.
Headlights get one blue, one yellow and one black ground each.
The red and red with white line go to battery or starter.
The last plug has one brown,one white,one blue with white line.
I know 1 must be for low 1 for high and the other I don't know or where I hook any of them in.
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mark75b
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I am lost my MG wiring diagram shows 3 wires to the light switch and 4 wires to the dimmer-flash to pass switch 2 of witch go to high and low beams.2 of my new wires must go to the last 2 on the dimmer and one to the light switch but does it replace one or join one and witch one.
Scott_Hower
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[ QUOTE ]
I am lost my MG wiring diagram shows 3 wires to the light switch and 4 wires to the dimmer-flash to pass switch 2 of witch go to high and low beams.2 of my new wires must go to the last 2 on the dimmer and one to the light switch but does it replace one or join one and witch one.
[/ QUOTE ]
You do not need to use any wiring at the headlight switch. Your best bet is to locate the relays out near the headlights, I mounted mine on the inner fender near the radiator support bracket. See photo.
1. On that side of the car, you should find the four bullet connectors which feed your existing headlights: one pair of blue with a red tracer. These are the left and right low beam. The other two are blue with a white tracer (left and right high beam). Disconnect these bullets.
2. Pick which side headlight wiring you want to use to operate the relays (left or right, you don't need both). Reinstall the bullet sleeve on the unused pair to prevent a dead short. The blue/red bullet gets connected to the relay low beam relay coil (pin 85). The blue/white gets connected to the high beam relay coil (pin 85). Connect pin 86 on both relays to ground. If you have wired this correctly, the low beam relay should click when you operate the headlight switch and the high beam should click when you operate the highbeam switch. If they don't click, you've got a wiring issue.
3. Whatever color wire is connected to pin 30 on both relays is your high current input (one for low beam, one for high beam). These get connected to the starter solenoid (solder on a ring terminal).
4. Whatever color wire is connected to pin 87 on both relays should already be connected to your headlight plugs. No probs here.
(note pins 87 and 30 may be reversed without problems, but that is how they are commonly wired).
The only other thing you need to connect is the ground at the headlight.
I am lost my MG wiring diagram shows 3 wires to the light switch and 4 wires to the dimmer-flash to pass switch 2 of witch go to high and low beams.2 of my new wires must go to the last 2 on the dimmer and one to the light switch but does it replace one or join one and witch one.
[/ QUOTE ]
You do not need to use any wiring at the headlight switch. Your best bet is to locate the relays out near the headlights, I mounted mine on the inner fender near the radiator support bracket. See photo.
1. On that side of the car, you should find the four bullet connectors which feed your existing headlights: one pair of blue with a red tracer. These are the left and right low beam. The other two are blue with a white tracer (left and right high beam). Disconnect these bullets.
2. Pick which side headlight wiring you want to use to operate the relays (left or right, you don't need both). Reinstall the bullet sleeve on the unused pair to prevent a dead short. The blue/red bullet gets connected to the relay low beam relay coil (pin 85). The blue/white gets connected to the high beam relay coil (pin 85). Connect pin 86 on both relays to ground. If you have wired this correctly, the low beam relay should click when you operate the headlight switch and the high beam should click when you operate the highbeam switch. If they don't click, you've got a wiring issue.
3. Whatever color wire is connected to pin 30 on both relays is your high current input (one for low beam, one for high beam). These get connected to the starter solenoid (solder on a ring terminal).
4. Whatever color wire is connected to pin 87 on both relays should already be connected to your headlight plugs. No probs here.
(note pins 87 and 30 may be reversed without problems, but that is how they are commonly wired).
The only other thing you need to connect is the ground at the headlight.
Nunyas
Yoda
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https://www.advanceautowire.com/
has a PDF file with all the different wiring diagrams for MGBs on their site. When I get around to uprating my headlights, I think I'm going to use their headlight relay kit. It has enough relays and fuses to do the headlights and then some. /ubbthreads/images/graemlins/smirk.gif
has a PDF file with all the different wiring diagrams for MGBs on their site. When I get around to uprating my headlights, I think I'm going to use their headlight relay kit. It has enough relays and fuses to do the headlights and then some. /ubbthreads/images/graemlins/smirk.gif
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mark75b
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HI Scott and Nunyas thanks for your help. My Harness has the power coming in on pin 86 if thats the back left one.2outputs one to each headlight on pin 85 if thats the front left one. a comon wire to both pin 87(if front right) that goes to my 3rd plug that I think must be a ground. then 1 brown wire to pin 30(back right) of one relay and one white to pin 30 of the other both also go to that 3rd plug. So if I cut the wires off the 3rd plug put the comon one to ground and the brown and white one to the wiers at the bullet connectors you wrote about what do you think?
Scott_Hower
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Can you post a photo of what you have? The relays must be labeled with pin #s; we need to know what color wire goes to what pins. Each harness shold be completely independant.
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mark75b
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Scott good idea pictures, I don't know how to post them but I could e-mail them to you My e-mail is mnmalarin@comcast.net I am not to good on the PC but my wife can help me. We have e-mailed pictures in the past. Also I see the MG in the hanger with the 2 BMW's but where is the Z4