Ignition and Fuel Light Resistors

[Viv James TraX Interconnect (Pty.) Ltd]

1. The coiled resistance wire on Ign. and Fuel lights of my cream TC nearing completion has long since gone to wherever these things go. Who can tell me the Ohmic value of these coils so I can replace them with resistors? 2. What is the bulb spec (Watts) for these lamps? Viv

[Dean Jensen]

Viv I am not sure what spec voltage/watts the original bulbs were for the fuel light. If you can find a 12 volt bulb, that will fit the socket, you do not need the resistance wire. My experience has been that the correct bulb burns out way to easily, leaving you along side of the road. If you can find a 14 volt bulb that fits the socket this would be even better. If you want to use something other than a 12 volt bulb (smaller) tell me the voltage and I will figure the resistance for you. Anything that fits in the socket will do. I have never had a problem with brightness (watts) so I do not think this is a consideration. You can not pull enough current on the wires or contact to create a problem, the bulbs are just too small, and finally no one will know that you do not have an original bulb behind the lens. Dean -----Original Message----- From: Viv James TraX Interconnect (Pty.) Ltd [mailto:viv@trax.co.za] Sent: Wednesday, February 20, 2002 5:55 AM To: mg-tabc@yahoogroups.com Subject: [mg-tabc] Ignition and Fuel Light Resistors 1. The coiled resistance wire on Ign. and Fuel lights of my cream TC nearing completion has long since gone to wherever these things go. Who can tell me the Ohmic value of these coils so I can replace them with resistors? 2. What is the bulb spec (Watts) for these lamps? Viv Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

[Viv James TraX Interconnect (Pty.) Ltd]

Thanks all of you for some interesting comments about the indicator lamps. 1. I think Dean's 12V bulb for the ignition will work OK but was the old coiled wire not perhaps in parallel with the bulb? This way, if the bulb blows, life goes on. I don't have the wiring diagram here with me so I'm not sure what else goes thru the bulb. More on this later. 2. Following on from Eric's comments nad Dean's suggestions, using just a bulb as a current limiting device for the fuel contacts is not clever - I think. Filament resistance is very low when cold and only increases as it warms up. This means a high current just as the contacts close. This you don't want. A series resistor should be all that is necessary and I guess I'll have to look at bulb wattages etc. and use Ohms law. I just thought someone else might have done this for me. Viv

[David & Joyce Edgar]

>1. I think Dean's 12V bulb for the ignition will work OK but was the old >coiled wire not perhaps in parallel with the bulb? This way, if the bulb >blows, life goes on. I don't have the wiring diagram here with me so >I'm not sure what else goes thru the bulb. More on this later.

As I understand it the current through the bulb does not feed anything. The bulb is located between the IGN switch and the Dynamo. When the dynamo is at rest, current flows from the IGN switch, through the bulb and throught the Dynamo to ground resulting in the bulb glowing. When the Dynamo starts rotating up to speed and generates, voltage is equal on both sides of the bulb and therefore no current flows. The bulb then stops glowing. If the bulb breaks nothig else is effected. Only question I have is would a Datsun bulb last longer and glow brighter? Maybe I should go halogen. Maybe I ought to give it a rest and quit now. (smile) David Edgar, TC 5108 El Cajon, California

[Dave & Diana Dwyer]

Viv 1. Ignition light - the 12V bulb in the ignition light certainly works: our J2 has been that way for thirty years. The resistance is in series with the light, not in parallel. If the bulb or resistor fails, everything else goes on working, I'm pretty sure. 2. Fuel warning light - I don't think the original warning lamp has a resistance in series as it's a quite different lamp to the ignition warning. I've been told that at some time the fuel warning lamps were unavailable and some suppliers sold the other type instead, so some cars may have had them fitted then, hence the confusion. Regards Dave Dwyer J2, TA, TC

[i.thomson@talk21.com]

As I see it nobody to my knowledge has ever burst into flames due to eith a short or open circuit on the fuel bulb so why worry. I certainly have never heard of a resistance wire in there (note to self - check the wiring diagram, you may learn something) and certainly never fitted on when I rebuilt the car. None came with new wiring loom and it all works! At least that bit does anyway. Ian Thomson. =--------------

> Thanks all of you for some interesting comments about the indicator >lamps. > >1. I think Dean's 12V bulb for the ignition will work OK but was the old >coiled wire not perhaps in parallel with the bulb? This way, if the bulb >blows, life goes on. I don't have the wiring diagram here with me so >I'm not sure what else goes thru the bulb. More on this later. > >2. Following on from Eric's comments nad Dean's suggestions, using >just a bulb as a current limiting device for the fuel contacts is not >clever - I think. Filament resistance is very low when cold and only >increases as it warms up. This means a high current just as the >contacts close. This you don't want. A series resistor should be all that >is necessary and I guess I'll have to look at bulb wattages etc. and >use Ohms law. I just thought someone else might have done this for >me. > >Viv > > > >Your use of Yahoo! Groups is subject to http://talk21.btopenworld.com/redirect.html?http://docs.yahoo.com/info/terms/'>[url=http://docs.yahoo.com/info/terms/http://docs.yahoo.com/info/terms/>

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