Graham C Posted July 11 Report Share Posted July 11 Currently getting a GT6 mk3 on the road, tested indicators - both sides worked when engine on. Hazard lights did not, nothing when switched on. Indicators have always flashed slowly but worked. Changed the flasher unit, hazards worked (without engine running) and one side (passenger) indicator worked - flashed (with engine running) while drivers side just lit up and did not flash. I am thinking that I may have a high resistance on the drivers side wiring, any ideas?Graham Note: flashed units seem to have different specs. Graham Link to comment Share on other sites More sharing options...
Steve P Posted July 11 Report Share Posted July 11 Commonest issue with our cars is poor earths, check that first. S Link to comment Share on other sites More sharing options...
Nigel Clark Posted July 11 Report Share Posted July 11 I had a problem with the hazards on my Mk3 GT6 many years ago. It turned out to be poor contact in the hazard switch, easily cured by spraying in contact cleaner while flicking the switch vigorously back and forth. Nigel Link to comment Share on other sites More sharing options...
Graham C Posted July 11 Author Report Share Posted July 11 Sorry just to make it clearer, new flasher - hazards work, old flasher unit does not work. New flasher unit - left indicators when switched from column switch works, however driver side indicators when switch from column just light up but do not flash. However when operating left and right indicators using old flasher unit both worked. I assume the hazard is powered direct from battery , while column switch is powered through ignition switch, both use the same wiring the lights. Can't image of is an earth problem as lights work if using a combination of flasher units. Graham Link to comment Share on other sites More sharing options...
chrishawley Posted July 11 Report Share Posted July 11 (edited) The feed to the hazard flash unit is unswitched, fused, via the purple wire which picks up from C2 on the horn relay. The feed to the direction flasher is fused, switched (ignition switch) via a green wire which picks up from the back of the voltage stabiliser. But it does not go directly to the flasher unit: The green wire goes to terminal 8 on the hazard flasher switch, the pathway is passed through the switch to terminal 7 from which a Light Green/Slate wire goes to the direction flasher unit. From the DRU there is feed forward to the column direction switch which then sends the feed to off, left or right depending on selection. Thus one candidate for the pattern of symptoms described is faulty direction switch. It can have dirty or decayed contacts, or contacts that arc and get hot. A diagnostic test is the find the relevant wires in the bundle under the steering column and with a jumper lead join Light Green/Slate on to GreenRed then GreenWhite. If all the direction flashers work then that strongly implicates the direction column switch. But poor forward or earth pathway is consistent with what you describe. That the right hand side indicators work with one flasher unit but not another could be as follows. For the two pin (vane type) flasher unit a certain level of current is needed to heat up and therefore make/break the circuit. The two units could just vary slightly with one being slightly more sensitive than the other in a situation where current is marginal. Poor pathway at the rear lights such is such a common Spitfire/GT6 problem that it's always worth exploring even just for exclusion. Factors can be • bulb poor (worn or oxidised contacts) • contacts on bulb holder oxidised, weak or making poor contact• Poor contact between the 'teeth' on the bulb holder and the body of the light unit • Earth stud on the rear light unit broken (many are) so earth floating free without an alternative attachment being made. We must not overlook the front indiator bulb: this can be in a poor state much as the back. A remote possibility may be the night dimming relay (if your vehicle has one). But this would be the last thing to explore due to its inacessible location (tucked up behind the left rear wing). Edited July 12 by chrishawley Link to comment Share on other sites More sharing options...
Graham C Posted July 11 Author Report Share Posted July 11 Thank you Chris for a detailed explanation, I will work through this. My gut feeling is the direction indicator switch has a poor contact, so high resistance. I was unsure of the wiring but you have give a good explanation. Cheers Graham Link to comment Share on other sites More sharing options...
Graham C Posted July 14 Author Report Share Posted July 14 Checked the switch and also stripped it down and cleaned it. Very dirty. Check the earthquake cleaned on the drivers side, (side where lights stayed on) Decided fault was with direction indicator flasher unit. Problem not really sure where it is located, besides behind dash board. Removed dash board, what a pain, located unit and replaced it with the original hazard flasher unit and everything worked. Refitted dash, lost one of the knurled nuts for the Speedo clamp. Does anyone know the thread size for these? Thank all for your help, original did not realise that the car had two flashing units which throw my initial investigation. Closed to MOT 😀😀😀 Graham Link to comment Share on other sites More sharing options...
Nigel Clark Posted July 14 Report Share Posted July 14 I feel your pain... If memory serves, and it's less reliable these days, the speedo attachment nuts are a BA thread, probably 2BA. Nigel Link to comment Share on other sites More sharing options...
johny Posted July 14 Report Share Posted July 14 They are available from the suppliers I think.... Link to comment Share on other sites More sharing options...
Graham C Posted July 14 Author Report Share Posted July 14 Thank, thought of supplier - 50p nut and £5 postage.😂😂😂 Graham Link to comment Share on other sites More sharing options...
Graham C Posted July 14 Author Report Share Posted July 14 Sorry being a bit lazy with my request. Quick Google seems it is 3BA. Off to an engineering supplier tomorrow. Cheers All Graham Link to comment Share on other sites More sharing options...
johny Posted July 14 Report Share Posted July 14 19 minutes ago, Graham C said: Thank, thought of supplier - 50p nut and £5 postage.😂😂😂 Graham I always have a list of bits to buy but anyway I think that nut could wait until your next shop😂 Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 15 Report Share Posted July 15 tip ....drill hole in new knurled nut and add 12" of cotton so when it flies into the abyss you can retrieve it Pete Link to comment Share on other sites More sharing options...
Graham C Posted July 15 Author Report Share Posted July 15 Thank you Pete, a bit toooo late with the advice. I am hoping it may drop out when driving the car.😁😁😁 Graham Link to comment Share on other sites More sharing options...
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