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MG MGB Technical - Directional trouble

All right call me lazy, I know this must have been discussed in archieved threads. Started the 74.5 "B" yesterday for the first time in 3 weeks. (Weather lousy, snow, snow, snow!) Started right up, no problem. Went through my usual checklist, hello, what's this, directionals not working? Every other electrical function working fine, from wipers to cigar lighter. Oh, and the hazard flashers ARE working as well as the headlights and high beams. The directionals WERE working 3weeks prior when I was able to take it out for an hours cruise. The car is stored at an unheated but dry self-storage unit so I'm not able to spend much time messing with it. I am assuming some corrosion in a connection, any ideas on the best place to start?
John

I'd go with the flasher unit. Here in the UK they are only about $5 as I recall, so if they're that cheap over the pond I'd go with swapping a new one in to see if it helps.
dave

John. I suspect Dave is correct. Do you have power going into the flasher? If so, that is the next thing to check. If no power into the flasher, check the power out of the hazzard light system. Les
Les Bengtson

Would someone please tell me in simple layman's terms how to check if there is power going into the flasher? Can I easily check if the flasher is still good? Also, how do I check if the turn signal switch is working properly? I took it off the steering column, cleaned it with contact cleaner, and replaced it. Before doing that, I had the right side signals front and back working. Now neither side front or back works. The hazards work all the way around. Wiring drives me nuts! Thanks for any help.
cg pieper

Les and Dave,
Is the hazard flasher and turn signal flasher 2 different units? Like my question stated, the car is stored at a storage garage a ways from my house. It's unheated so when I get there I'd like to have a good idea where to look so I don't freeze my fingers off (5 days to spring, thank God!).
John

The hazard flasher is made for a higher load. However, you can switch them over briefly as a test.

Do you have a wiring diagram. If you do trace the wires that form that part of the indicator circuit that is common to both. You may find a wire has dropped out.

David
David Witham

Dave,
I found a web site with wiring diagrams and hopefully this weekend I can bring the "B" home for a visit and a little sorting out. Thanks for your help. Also I need to get a proper multimeter and learn how to use it.
John

On a car with factory hazards where the turn signals don't work at all, i.e. no glow from the corners or the tell-tales, the hazard switch is often the problem due to lack of use. Flick the hazard switch on and off a few times and see if that makes a difference. If so dismantle the switch in a poly bag, clean out the old grease and put in some fresh stuff.

If not that locate the turn flasher, which is behind the dash in a spring-clip screwed to the firewall, and has green and light-green brown wires. The hazard flasher can be in a similar location, but that has brown and light-green/brown wires. The brown for the hazards should be live all the time, and its light-green brown should *not* normally show 12v. The green for the turns should be live when the ignition is switched on, and the light-green/brown *should* normally show 12v when they are not switched on. On this unit 12v one side but not the other means a bad flasher unit. Make sure you get a replacement that gives the proper indication when one corner is out, some units are little more than hazard flashers and are a safety hazard.

As David says you *can* use a hazard flasher for testing the turn signal circuit, but not the other way round. But even if the hazard flasher flashes in the turn signal position and the turn flasher doesn't, it doesn't necessarily mean the turn flasher is bad, if the corners (or only one of them) are lighting it could well be bad connections that are the problem.
Paul Hunt

cg. The simplist way to check for power is to simply use a test light. This is simply a probe with a light in the clear, plastic handle and a ground wire. Clip the ground wire to any good ground, then touch the probe to wires, fuses, terminals, etc. to see if there is power present. If you wished to check for power into the number three fuse, you would clip to ground clip to something like the alternator case or bracket. Then, touch the wire going into the front of the fuse box. (You should see power present if the ignition switch is in the run position and no power if it is in the off position.) Let us say that you do have power because the engine is running and you are trying to find the problem with your brake lights and gauges. So, you have power at the terminal. Next, you check for power at the clip that holds the front end of the fuse. You have good power there, indicating a good connection between the wires and the fuse box. You check the front metal cap of the fuse and your light does not come on. This tells you that there is a problem between the clips holding the fuse and the metal terminal of the fuse. You clean the fuse and the holder. You get light when touching the fuse, the system now works, you have found and corrected the problem.

If you had not found and corrected the problem, you would continue to use your test light going through the system until you did find the problem. Test lights are quick, easy to use, rugged and inexpensive. They will not tell you the exact voltage present, as a volt meter will, but are still very useful for initial diagnosis. Hope this is what you were looking for. If not, post again and I will try to do better.

John. My 77 and 79s have the two flasher units under the center of the dash on the passanger side. Both are attached to the firewall with a single screw. The hazzard flasher is above the turn signal flasher on my cars.

Les
Les Bengtson

This thread was discussed between 14/03/2005 and 15/03/2005

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