Weird flashing indicator warning light behaviour

[chrisjp]

I'm in the process of getting my 1964 Mk 2 A40 back on the road after a very long period of disuse at the back of my garage. This A40 is the earlier Mk2 with separate LH and RH flashing indicator warning lights in the speedo.
The flashing indicators outside work fine, but the LH warning light flashes 3 times and then goes out, while the RH one sometimes (but not always) flashes once and then goes out.
I could maybe understand it if the warning lights didn't flash at all, but I can't fathom this weird behaviour. It's not helped because the only Mk2 wiring diagram in the workshop manual is for the later Mk2 with the single warning light on the end of the flasher stalk.
Has anyone else had this issue and fixed it, or can anyone offer any suggestions?

[Keith Bennett]

Could there be a poor earthing problem?

[chrisjp]

Thanks for your response and yes, that thought had occurred to me also.
I've checked and cleaned the flasher unit earth and the earthing of the dashboard warning lights. I can't think that the earthing of the 4 outside flasher lights is at fault otherwise they wouldn't work. I'm not sure where else to look, short of ripping out the whole wiring loom.
I harbour a vain hope that somone else has suffered the same malady and knows how to fix it!
It wouldn't be so bad if I could actually hear the flasher unit ticking when it's operating but of course it's mounted on the bulkhead within the engine compartment, so is inaudible inside the car.
The A40 has been off the road for around 40 years - at the back of my dry garage and, as far as I can recall, the flashers and dashboard warning lights were working OK then.
I've found that one of the connections on the flasher unit is live continuously when the ignition is on but the flashers are off, and is live in line with the flashing when either side flashers are operating. So a possible workaround would be to connect this to the dashboard warning lights. Both would flash when either LH or RH flashers were operating, but at least it would serve as a warning that they were on.

[chrisjp]

A bit more research has turned up a schematic of the innards of the FL5 flasher unit. It appears that this has two sets on contacts on bimetal strips, arranged around a steel core - one to flash the outside direction indicators, the second to flash the dashboard warning lights.
So it might be that the second set of contacts is faulty.
I've tried replacing the flasher unit with what is claimed to be a modern replacement but, although this flashes the outside indicators, it still doesn't flash the warning lights.
So, I'm on the lookout for a working used, or new old stock, original Lucas FL5 flasher unit, if anyone has one lying about!
Cheers

[exlkrs]

Are you terribly bothered about originality? If not, check Classic LEDs website. Very helpful too on the phone. Does both Positive and Negative Earth stuff too.

[chrisjp]

Ahh thanks, but the problem I have is not with the pilot light bulbs themselves - these work fine when supplied with power independently.
The problem is that the wiring loom connections from the flasher unit do not supply power to these bulbs consistently when the flashers are operating.
I've worked around this problem by identifying the terminal on the flasher unit that supplies a flashing current when it's operating, and connecting this to two new bulbs and holders that slot into the pilot light holes in the dashboard in the place of the original wiring loom bulb holders - which have had their bulbs removed.
This has the downside that both LH and RH pilot lights flash when either the LH or RH flashers are operating, but at least I have a warning that the flashers are on.
I've done this because, in the absence of any fellow A40 owner experiencing the same issue and knowing how to solve it, the only way I could see to resolve the original problem would be to completely remove the car's wiring loom and examine all connections in it - and I really didn't want to do that!

[exlkrs]

Ahh thanks, but the problem I have is not with the pilot light bulbs themselves - these work fine when supplied with power independently.
The problem is that the wiring loom connections from the flasher unit do not supply power to these bulbs consistently when the flashers are operating.
I've worked around this problem by identifying the terminal on the flasher unit that supplies a flashing current when it's operating, and connecting this to two new bulbs and holders that slot into the pilot light holes in the dashboard in the place of the original wiring loom bulb holders - which have had their bulbs removed.
This has the downside that both LH and RH pilot lights flash when either the LH or RH flashers are operating, but at least I have a warning that the flashers are on.
I've done this because, in the absence of any fellow A40 owner experiencing the same issue and knowing how to solve it, the only way I could see to resolve the original problem would be to completely remove the car's wiring loom and examine all connections in it - and I really didn't want to do that!

They do flasher units as well as bulbs!