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MG MGB Technical - Slow indicator blink rate ?

Hi there, need to MOT by B-GT. It has a very slow blink rate on the indicators. All bulbs are working, but very slow.

Is this a typical fault, that some one could help with? Electrical wiring issue, too much resistance in circuit, relay issue..??

Many thanks James Eastwood

I don't believe it makes a difference to the indicaor wiring, but vehicle is a factory V8.
James Eastwood

Needs to be 60-120 per minute to pass. They usually work faster with the engine running. Usual culprit is poor earths-try touching the metal side of the bulb (in its holder) with a bit of wire to a known GOOD earth. (It should speed up) If not then undoing and cleaning ALL the relevant bullet connectors with emery paper and /or replacing the "female" connectors is needed. Beware when cleaning of disturbing other connections.

Simple 2 pin flasher units are cheap and available from Halfords so you could try replacing it before cleaning off the corrosion. Make sure you identify which flasher unit as you may have a hazard flasher aswell. Your relevant wiring diagram will show the wire colours and help identify the correct flasher.
It could also be the contacts on the indicator stalk which necessitates removing the cowl to get at them.

AS it seems to be both sides start at the fuses and work forwards ( fuse to flasher to indicator switch to bulbs)when checking connections. What year is it? Others may have more specific recommendations.
Michael Beswick

Do the hazard lights blink at normal speed? If yes, then my $5 guess would be a tired indicator relay unit.

If hazards are slow, then i would follow the trail as Michael set out.

One thing to add though, I belive that sometimes the bridge in the hazard switch can slow things down if it cruds up. So it might be worth bridging the two green wires at the back of the hazard switch - or take them off and hold them together, then see if this changes things.

And, no, it makes no difference if your car is a V8.
Hal Adams

James

My guess is it's the 2 pin thermal flasher unit you have that's causing the problem, if so change it for an electronic version. You can buy the 3 pin units quite cheaply which requires an earth wire or you can now get a 2 pin electronic unit, I haven't tried these though.

http://www.ebay.co.uk/itm/Land-Rover-Discovery-Flasher-Relay-YWT10003-/220917449027?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item336fb4c143

http://www.ebay.co.uk/itm/Upgrade-2-Pin-ELECTRONIC-Flasher-Relay-MGB-MG-midget-/200644688972?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2eb75afc4c

Bob
R.A Davis

Gents,

Many thanks. Plan of action;
* check the hazard flash rate
* check the earth at the bulbs
* clean the bulb contacts
* repalce flasher unit.

Big help, thanks James
James Eastwood

My '79 BGT suffered from slow blink rate. Investigating this, I found the multi-pole plug/socket type connector behind the dash (just to the left of the wiper motor), the one with white + brown + red/white + green/white wires attached to it, showed signs of overheating and the plastic body of the plug/socket was partly melted. The white wire is the 12v supply from the ignition switch which feeds the following circuits:

Ignition switch relay
Ignition coil
Tacho
Heated rear window + indic lamp
Heater fan
Indicators + indic lamp

The connector contacts for the white wire appeared brownish/tarnished, presumably due to overheating. This probably caused a volt drop on the above circuits. The indicators would only blink slowly when the engine was idling, and wouldn't blink if the engine wasn't running.

The connector was difficult to open up so I didn't bother trying to clean it up. I cut the white wire off both sides of the connector and fitted a new single connector (with screw terminals). After this, the blink rate was ok.
Brian Shaw

Gents, thanks very much for feedback.

I cleaned the bulb connections but it made no difference, and they were all very similar brightness. I didn't wan to go round the car disturbing all the other connections (good point Michael) so opted to exchange the flasher unit next.

Having removed it from the car, I prized off the alluminium cover and found the workings. Ha, Ha! I tought!

I gave the contacts a clean with some 800 grade.. slightly better flash rate, then I very gently tweaked the corner of the spring plate were the hot strip is fixed (it runs diagonlay accros under the larger rectangular plate. It took a couple of goes, but I adjusted it perfectly near 100 flashes/minute.

All back together works great, no cost, no trip to the store, MOT man satisfied.!
James Eastwood

Thank you James: just the sort of remedy that makes this forum so useful.
c cummins

This thread was discussed between 16/10/2012 and 19/10/2012

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