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MG MGB Technical - Now down to the Hazard Switch

Moving across the dash on my '70 BGT with help from the list I am now ready to remedy the Haazard flasher switch/. I have directionals but no Hazard lights, actually have no power at the switch at all. Where does the switch/flasher get it's power from? On my diagram it looks to be from the starter solonoid?. I have NO power at the fusible link inside the console. All fuses are good. Checked all connections on the switch with test lamp= NO Power. Just want to make sure where to start from.
Thanks for any suggestions.
Mike
MK Mike

Looks like 12v comes from the sealed connection behind the dash, through a 4-way bullet connector which only has 2 wires, a 2-way bullet connector, and an inline fuse, to the flasher unit. All these are browns, including both sides of the in-line fuse, so you should be able to identify the correct fuse as it is the only one like that. Then from the other side of the flasher unit to the hazard switch on a light-green/brown. I don't know where the 4-way bullet connector is located, it could also be behind the console as an earlier diagram shows the optional radio fed from it. The flasher unit will show a low resistance 12v only on the input side (X on the diagram), may show a high-resistance 12v on the output side (L), so it depends whether you use a voltmeter or a test-lamp as to what you will see. However with a working flasher unit if you connect a test-lamp it may well start flashing, certainly should with a heavier load of at least one flasher bulb, or the unit is faulty. There may also be a light-green/purple on the P terminal of the flasher unit going to the repeater (not that it needs one, you have two right in front of you already!).
Paul Hunt 2

I found a cut brown wire at the large "block" under the steering column. Reconnect and I now have power at the switch. At bottom green wire on switch lamp glows, it also glows at one other upstream terminal on the switch, when switch is in the off position, when switched to the ON position the light goes out. Does not seem right. BUT I still have no power (no lamp) at the fusible link??? where should that power be coming from? headlamp switch??
Mike
MK Mike

Ok, Paul. I have power to the switch and I have SWITCHED Power from the switch to the Flasher, Meaning power is at 2 terminals of the flasher when switch is in ON position. Now with that I also see power at the fusible link. I am assuming that I will NOT see power at the repeater bulb socket if the flasher is not operating?? That's as far as I can go until I get a new flashere to test. I tried 2 old spares I had around but no flashers. Still not sure if I have it all right yet.
MK Mike

Make yourself an enlarged print of the wiring diagram. Wiring diagrams are available at http://www.advanceautowire.com click on stock schematics

Hazard switch

pin 1: green wire indirectly from fuse box
incoming power for the turn signals

pin 2: green wire to turn signal flasher
outgoing power for the turn signals

pin 3: green/white wire to the right side indicator lamps, energized when the hazard lights are turned on

pin 4: unused

pin 5: lightgreen/brown wire from hazard flasher
incoming power for the hazard lights

pin 6: green/red wire to the left side indicator lamps, energized when the hazard lights are turned on

Turn signals are powered by the green circuit.
Hazard lights are powered by the brown circuit.
Kimberly

There should be power through the in-line fuse (brown to brown) all the time.

When the switch is *off* the two greens are connected together to power the turn flasher, one green carries 12v in from the fusebox with the ignition on, the other feeds it on to the turn flasher unit. The other four switch terminals should be isolated from all other terminals.

When the switch is *on* the two green terminals should be isolated, and the other four terminals all connected together. This connects the turn signal bulbs and the repeater bulb to the output of the flasher unit, which is what starts it flashing.

You can test everything *without* a working flasher unit by linking the brown and light-green/brown terminals on the hazard flasher unit together. Now when you turn the hazard switch on the four turn bulbs on the corners of the car, the repeater lamps on the dash, and the hazard repeater lamp, should all glow continuously until you turn the hazard switch off.
Paul Hunt 2

This thread was discussed between 07/11/2006 and 08/11/2006

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