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Deep fried relays

Posted: Sun Aug 28, 2011 9:21 pm
by rupert
Hi MMOC people,

I wonder if you could help me with a little problem I'm having with Molly. I replaced the flasher relay a couple of weeks ago and it worked for a few seconds - then pop.... so I chucked in another one (I always buy two of everything - I will need a spare!) and that one lasted a few days.

So my question is, do I have a bunch of duff relays or is there something wrong with my wiring which is overloading the relays? If so how can I tell?!

The added complication is that Molly is 1962 change-over model with a large (expensive!) relay on the inner wing, could this be dead and overloading the flasher relays?

By the way - you may notice from the piccie below that Mol has a tow bar, the trailer hasn't been used since long before the relays started popping so I don't think it could be that (but I could be wrong)

thanks in advance!

Rupert[frame]Image[/frame]

Re: Deep fried relays

Posted: Sun Aug 28, 2011 10:03 pm
by bmcecosse
I'm guessing you mean 'flasher unit' rather than 'relay' - and yes - I suspect duff units.

Re: Deep fried relays

Posted: Mon Aug 29, 2011 9:06 am
by MarkyB
Did they both pop when you indicated the same direction?

Wiring for trailer electrics can be very substandard, I'd start checking with a meter before throwing any more flasher units at it.

Re: Deep fried relays

Posted: Wed Aug 31, 2011 4:15 am
by Fingolfin
The cylindrical flasher unit (which is the same on the relay-fitted Minor as on all the others, so far as I'm aware) is very prone to substandard replacement quality. I.E., find new old stock? Dunno.

I've recently been deeply involved with the indicator stuff, and my Mog has the same relay sort of indicators as yours...so I know all about this... :roll:

Re: Deep fried relays

Posted: Wed Aug 31, 2011 10:48 pm
by rupert
Hi there, thanks for the info. With MarkyB's advice, I've been checking into the problem tonight and all the connections seem to be ok. The flasher stalk tell-tale works fine. As do all four indicator lights when driven from the output of the eight way relay. I think the left hand set were a little dodgy for a while but some cleaning got them going again.

Once I was happy with everything (I cleaned a few contacts) I gingerly fitted the new flasher unit and it seemed to work ok!

I did a little more playing around and testing and it all appeard fine. The flasher unit wasn't getting too hot.

Then I noticed something funny. The tell-tale light on the indicator stalk was on all the time! I started checking over hte new unit and when one of the contacts was live, the other two were live! i.e. it flashes on off on off rather than off on off on

I've disabled the tell-tale for the timebeing while I scratch my head and work out what is going on!

For info, the two dead units were new "electronic" ones. The new one is mechanical.

Finfolfin, I'm in the midst of learning about indicator circuits inside out too!

MarkyB, the trailer eletrics is pretty solid, I put it in last year with brand new cables, connectors etc. but I checked them anyway!

BMCEcosse, thanks for the tip on the names, it makes searching for a new one much easier! And I'm thinking duff units too

thanks everyone again

Rupert