Page 1 of 1

Indicator relay

PostPosted: Thu Jan 01, 2015 2:11 pm
by john.p.clegg
Dear All
Of the electrical gurus amongst us,has anyone taken apart the metal can that houses the indicator flasher gubbins and faulted it..?
The reason I ask is that I've done just that...on two unknown relays...and both seem to have a part missing,the second contact that operates the pilot light in the speedo.... this seems to be too much of a coincidence

N.B.

http://mgaguru.com/mgtech/electric/et104.htm



I have managed to get a pilot light operation by connecting a lamp between + (battery) and L ( load) ( small current draw-not enough to energise the flasher) and this gives a good " tell-tale " of the indicators working,but is not as in the wiring diagram and I cannot get an output from the P terminal

Any ideas?

John :wink:

Re: Indicator relay

PostPosted: Thu Jan 01, 2015 4:36 pm
by AHM
I have one of the new replacements apart.

The P terminal is connected to a copper strip - Schematically it is the same as the one on the MGA diagram. (Except I'm not sure what the curved line between B and P is supposed to represent) So when the bi-metallic strip pops the circuit is made and the lights come on.

Re: Indicator relay

PostPosted: Thu Jan 01, 2015 4:41 pm
by john.p.clegg
I think the curved line,flat across the bottom is to represent the case..?

John :wink:

Re: Indicator relay

PostPosted: Thu Jan 01, 2015 4:52 pm
by AHM
You have me intrigued so I took apart an old one which is heavier...
DSC_0003.jpg and


P terminal on the left on the left (Old) one - Connected by a short wire
and
On the right on the Right (new) one - copper strips on both parts.

Even more intrigued now as the old one (dated 1960) seems to operate by a magnetic coil rather than a bi-mettaic strip.

Re: Indicator relay

PostPosted: Thu Jan 01, 2015 8:37 pm
by billwill
If the lamp in the speedo has two independent connections, i.e. not grounded, you can get the desired flashing indication by connecting the bulb between the external left & right indicator bulbs (or the feeds to them).

High voltage on one side will pass through the speedo lamp then through the 'other' indicators bulbs to ground. There won't be enough current to actually light up the other indicators.

Re: Indicator relay

PostPosted: Thu Jan 01, 2015 8:57 pm
by john.p.clegg
AHM
The ones I took apart are as per the left hand item in the photo...BUT...they don't have a lever/contact on the right side as looking at your photo....is that the pilot light feed?

P.S. the bi-metallic strip seems to be the thin wire on the left under tension to an insulating ball near the base..

Thanks
John

Re: Indicator relay

PostPosted: Wed Jan 07, 2015 2:05 pm
by ricarbo
I haven't had to change mine, but have a question. Is there any problem in using a modern electronic flasher unit?
I see, for example, Holden sell a 3 terminal unit, No.080.082 for ?12.79 plus vat and postage. Without knowing, that looks suitable.
Regards
Richard

Re: Indicator relay

PostPosted: Wed Jan 07, 2015 8:14 pm
by ericbushby
john,
I am at the same point with mine, no output on P terminal.
The unit is new with the correct 47 watt rating.
I have it set up on the bench with a 12 volt power supply and two lamps. As yet I do not want to cut it open but I am wondering if I have bought the wrong one.
It doesn't seem to be a thermal device because if I change the load or vary the supply voltage the flash rate doesn't change . It was only ?4. 60
I will report back when I have an answer.
Eric in Burnley
1967 S3SE DHC.

Re: Indicator relay

PostPosted: Wed Jan 07, 2015 8:47 pm
by Geoffers71
I've just fitted what sounds like the same flasher unit, cost me ?4.50 too. However my p connection works fine, though the light is not too fiocussed on the green lens. This is because in order to fit the bulb holder to the speedo I had to trim the black tube which does the focussing bit. You have checked that the holder is earthed OK?

Re: Indicator relay

PostPosted: Wed Jan 07, 2015 9:12 pm
by ericbushby
Hello geoffers 71.
Is that your age or date of birth ?
Thankyou for your comments but this one doesn't work on the bench. I have tried a second one with similar results.
The lamp in the speedo was also very dim on mine as it is inserted into a black plastic tube in the back of the speedo. However when rummaging in the box of rubbish which came with the car I found a long slender lampholder which takes a small lamp and fits it right up to the lens and cured that problem.
Eric in Burnley
1967 S3SE Type 45

Re: Indicator relay

PostPosted: Wed Jan 07, 2015 10:19 pm
by john.p.clegg
Eric
Have you cured the problem or just the fittng...if not..these work..

http://www.ebay.co.uk/itm/502096-BR1797 ... 3a9565366b

John :wink:

Re: Indicator relay

PostPosted: Thu Jan 08, 2015 9:55 am
by ericbushby
Thankyou John.
The two new ones I have look identical to that. They came from Minisport and A1 Motors, both in Padiham. These shops usually know what they are talking about.
The next move is to borrow a known good one, but there is no urgency for this as it is only the indicator which doesn't work. I am on the case and will report in due course.
Eric in Burnley
1967 S3 SE Type 45

Re: Indicator relay

PostPosted: Sun Jan 18, 2015 11:12 am
by billwill
billwill wrote:If the lamp in the speedo has two independent connections, i.e. not grounded, you can get the desired flashing indication by connecting the bulb between the external left & right indicator bulbs (or the feeds to them).

High voltage on one side will pass through the speedo lamp then through the 'other' indicators bulbs to ground. There won't be enough current to actually light up the other indicators.



I just found the wiring diagram which shows the bulb wired in this manner.

Image

Re: Indicator relay

PostPosted: Sun Jan 18, 2015 2:47 pm
by ericbushby
Thanks Bill,
I can see how that works now. I might go that way when I have had a look at the wiring. Even my ''faulty'' units will work like that, but it is 2 degrees in the garage today so I will leave it a bit.
Eric in Burnley
1967 S3SE DHC

Re: Indicator relay

PostPosted: Fri Jan 23, 2015 5:16 pm
by ericbushby
ford focus.jpg and
I have a result. Not an answer, but a result all the same.
Bill, your method would have worked except that when I checked the lampholder, it had a small metal spring in the plastic tube which was earthed.
I went to see a friend who has a Series 4 and tried his flasher unit, which worked correctly in my car.
I bought a similar looking 3 terminal unit from the local car shop, but that had no output from terminal P either. That was returned to the shop and then I bought the identical one which is in my friends car.
This worked immediately and correctly.
The working one is on the left. It came from :- Auto Electric Supplies Ltd. http://www.autoelectricsupplies.co.uk
Stock No. 140102
Interestingly. when I cut open one of the traditional looking flashers it has electronic innards.
Does anybody want a slack handful of dodgy flasher units. Very cheap.
Eric in Burnley
S3SE DHC