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MG MGB Technical - Lighting Problems

I have a 71 mgb roadster, and am working to get the all lighting systems working. All lights work front, back and side when I turn on the parking lights or headlights. Turn signals on passenger side work, but not on the drivers side. When I turn all lights off, and turn on hazard switch, both rear amber signal lights blink, as does the passenger side front signal light. The driver side signal does not blink. I believe I have the wiring correct on the front lights, based on a clolred coded wiring diagram, have checked the grounds, and have cleaned the contacts for all lights and switched. The hazard switch is not new, but the light switch is. All bulbs are new and have been checked. The turn signal flasher is new, the hazard flasher is old, NAPA brand, and seems to work for three of the lights. My understanding is the turnsignals will not work correctly if the hazards do not, since the hazards cancel the signals. I am really frustrated. Does anyone have any thoughts or ideas on how to get the dirver side front signals to flash with the hazard switch? Thanks.
Curt

Curt - Start looking at the grounds at which ever corner is not working correctly. See my article on ground point preparation at: http://www.omgtr.ca/technical/General%20Technical/grounding.htm
In addition to looking at the point where the ground wire attaches to the chassis, look at the lamp sockets themselves. Manu of them are in two pieces that have been crimped together and the crimp will develope corrosion, stopping any current flow. About the only cure for this situation is new sockets. Good luck - Dave
David DuBois

The problem may be at the hazard flasher connections.
Dan Robinson

Further to Dave's comments, the steel lamp socket is crimped into the zinc lamp body with a brass washer between. The steel mounting studs are pressed into the lamp body, and the nuts are generally seated on a painted surface. All this makes for awful grounding, as the dissimilar metals with voltage across them create a corrosion machine. I have taken to soldering ground leads directly to the socket. It takes either a very heavy soldering iron, or careful use of a torch to solder this heavy metal successfully; be sure to remove the wire and socket internals first to avoid cooking them, and get the socket really clean, and use a paste non-acid flux.
Your problem is almost certainly at the LHF lamp ground, assuming the bulb is good. The hazard switch if bad will cause all the turnsignals to fail, but not some of them.
FRM
http//www.usachoice.net/gofanu
FR Millmore

If the drivers side doesn't flash when the hazards are on that explains why the turn signals don't work that side. You may find that the rear is glowing but the front isn't. The wiring only splits between front and rear lights where the main loom joins the rear loom by the fusebox, so it isn't anything to do with the hazard switch or hazard flasher.

If you don't get either end even glowing with the drivers side turn signal, or the dash telltale, then that is probably a problem with the turn switch or where it joins the main loom by the steering column.

CB cars don't have a wired ground for either the front or rear clusters, they rely on the mechanical fixings. If the front drivers turn/hazard light glows dimly that implies a bad ground, if it doesn't glow at all but the parking light glows OK that implies a disconnection. This could be anywhere back from the bulb holder, through the single connector by the headlight that side, or the 4-way connector by the fusebox.
Paul Hunt

Eliminate some things. i.e. Are you getting power to the front of the car when you turn on the turn signal or flasher? Check with tester (12v bulb tester) where your turn signal wire connects into the knot of snap connectors behind the grill. If you are getting power there (it oughta flash), then as these folks point out, it is further forward( if not further back), either in the wire itself (I had a wire broken inside the insulation an inch from the fixture/light socket) which you can test with a simple continuity tester after pulling the wire out of the connector under the grill or it is in the socket. I also had a bad socket on another one. Mine was just corroded so badly it couldn't be cleaned so I replaced it. It really just takes elimination till you find it. Is power getting from A to B then B to C then...etc. etc. Not nearly as mysterious as I used to make it while diagnosing electrical probs.
J.T. Bamford

This thread was discussed between 26/09/2004 and 27/09/2004

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