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MG TD TF 1500 - question about indicator relay

I'm hoping that someone who knows a lot more than i do about TD electronics can help share their knowledge about a situation i'm having with my car.

After four long years of restoration 'Frankie' is about to hit the road, so one thing i did today was to check the turn signals out. It seems that when i hit the left signal everything works fine (both front and rear signals work fine). But when i hit the the right signal the front signal works as it should, but instead of the right rear working, the left signal blinks.

I should say that the new wiring has been installed correctly, and the indicator box is new from Moss. One last thing i need to share is that, in my efforts to trouble-shoot the problem, i bypassed the flasher unit and energized the 3 terminal (the one going to the left rear) and the left rear light went on. But when i energized the 7 terminal (the one going to the right rear) the left rear lit again...

I'm really confused, but it sure looks like someone might have messed up the new wiring harness... All thought would be greatly appreciated..

Tom Crause

Did you disconnect the wires from the indicator box when you separately energized the terminals? If not, do so and retest, that will prove the harness and remove the possibility that there is feed via the indicator box.

Graeme
G Evans

Have you put LED bulbs in back where the problem is?
D mckellar

Hi Tom,

Probably not the fault but are you certain the bulbs are in the correct way round? If they are not the flasher speed normally is fast but it may cause something else. I would remove the wires to terminals 3/4/7/8 and connect individual bulbs to them (correct filaments or flashing speed will be wrong) and see if they work properly. If so the harness or bulb holders are at fault.

If you had the old relay box you could have converted this to new sealed relays available from Maplin for a few pounds. The react far quicker than the Lucas ones and don't corrode. I have schematic and layout drawings for both Maplin relays and standard automotive ones. Both conversions fit under the original relay box cover. If you want the drawings let me have your email address and I will send them to you.


Jan T
J Targosz

Don't forget, a broken filament can cross over to the other post inside the bulb and look like it's working AND short the system to make another bulb all the way out in Nebraska light up.

Check the bulbs too.
MAndrus

A big question would be do the 2 brake lights work? That proves volts are going to bulb and ground is good.
P G Gilvarry

I had a similar problem a few weeks ago. There are 2 points in the relay box and the one wasn't dis-engaging properly. easy to check - just pop the top off the box and watch the points as you turn on each indicator.
Chris Malcolm (TD29228)

Thanks for all the suggestions -- the knowledge of this group still astounds me after all these years.

And so you all know, my problem has been solved... And the source of the problem (as they usually do) can be traced back to this operators error...

As it turned out, i messed up when connecting the rear harness to the main harness, and inadvertently connected both rear turn signal wires to the left turn signal wire coming from the relay. A quick and easy fix, but boy do i feel dumb...

Well thanks for all your time and suggestions..
Tom Crause

Murphy's Law lives on!
P G Gilvarry

This thread was discussed between 13/04/2017 and 21/04/2017

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