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MG MGA - Flasher Unit

I'm being driven to near desperation by the failure of a new flasher unit to work properly (I think). Here are the symptons:
The flasher properly responds to the left and right front and back indicator lights but the panel light only flashes when indicating right. When indicating left it comes on once and then no more.
Does the fact that the panel flasher light works for the right hand mean that the flasher unit is OK and I have to look elsewhere for the problem? I've looked at Barney's circuit diagramme but can find no logic for whats happening. Any suggestions much appreciated.
J H Cole

Should have said its a MK 2 so no relay.
J H Cole

If the flasher unit works for RH it's probably fine. Although I have found that repro units do tend to flash too quickly.

Sounds to me like a bad earth, I assume that the LH indicators don't flash. Check the wiring to the indicators, if possible conect a test lamp to earth from the lamp cable, or put 12v directly into the LH circuit.

Neil
Neil McGurk

Neil is right about grounds. There is no difference left to right for the flasher. The resistance/current flow is the variable. Are any lights Dim? Are any connectors getting warm?
If it were me I would clean every connection in the circuit. Starting at the green wire from fuse to flasher. Green/brown flasher to switch. Green White and 4 connectors to rear. Green/red and 4 connectors to front. All four light fixtures and grounds.
The connectors in these systems have no moisture protection at all and get dirty quickly.

R J Brown

J H, This problem is often a poor earth at the warning/indicator light. It must be soundly earthed which can be a problem because of the paint. Try a separate earth from the globe holder to a solid earthing screw - there is one nearby - in the strut which supports the bottom edge of the dash.
Good luck, Barry
BM Gannon

Barry, A bad ground at the indicator lamp would not explain why the RH works and the LH does not.

JH, While you are checking the wiring, I suggest using dielectric grease on every connection and on the lamp sockets themselves. This will prevent the problem from reoccurring once it is fixed.

Although I started with a new wiring in 2001, I have not had any connection-related electrical problems since putting it together using dielectrig grease. It has been almost 7 years now. I do not know how many problems there were in the first 45 years of its life.

Chuck
C Schaefer

Neil- the left hand indicators do work, this is whats throwing me. BM- the body of the panel light indicator does not need to be earthed but the black return wire from the lamp does to complete the circuit. If the indicator lamp flashes for right hand turns this must mean that the earth is OK. All I can think of is that somewhere in the the indicator light circuit for the LHS there is a bad earth that means the current flow is reduced which in turn reduces the flow in the flasher unit and does not produce enough heat in the windings to activate the points. I've had this in the past but its always been accompanied by low flashing rate or poor light level none of which I have. I will have to go through Barneys test procedure and recheck connections. The bullet connectors in front of the radiator to the LHS are near impossible to reach. I wouldn't mind too much but the MOT is coming up next week and I think the indicators are part of the test.
J H Cole

As long as the indicators work OK it should be no problem for the MOT, just make sure you are sitting in the car to operate all the swtches etc.

However, something is very strange if it is only the panel light that does not flash with the LH indicators, but they flash normally, right? The RH side circuit works normally?

According to the electrical circuit there is no difference to the flasher unit or panel lamp whether the RH or LH indicator circuit is connected via the switch. The only way that I can see that the flasher unit can allow both an intermittent (flashing) current and a solid current to flow to the panel lamp is that there is different resistance in the two circuits. However that difference is not enough to prevent intermittent current to be passed to both exterior lamp circuits.

So the logical solutions are: 1) to find the (high)resistance (bad connection) in the LH circuit. That may be tricky as it is not enough to stop the system working normally? 2) Try a different flasher unit to see if it is more tolerant?

I know you probably checked this many times, but are you sure that the LH indicators flash when the panel lamp doesn't?

Neil

Neil McGurk

JH

Just putting my lateral thinking hat on. As it's a new flasher unit, have you connected up the 3 wires to the correct terminals?

Steve
Steve Gyles

This thread was discussed between 27/02/2008 and 28/02/2008

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