Pogo Posted July 12, 2019 Report Share Posted July 12, 2019 (edited) Hi All I am still rewiring my TR6 (yes - still!). I have a query. My old wiring had a thin brown wire that was cut off (no connector and not wired to anything), near the alternator. I told Autosparks this when I ordered my new loom (sent them the above picture) and the new loom also has a thin brown wire but it has a spade terminal on it. It seems that the other end goes to the connector block on the inner wing. The alternator wiring has been beefed up (as recommended by Autosparks) and I have replaced the Ammenter with a Voltmeter So - my question is - where does this wire go? Any help much appreciated. Thanks Rog Edited July 12, 2019 by Pogo Quote Link to post Share on other sites
ntc Posted July 12, 2019 Report Share Posted July 12, 2019 Roger It is there for the different types of alternators that was fitted,I seem to remember is was for the charging light. N Quote Link to post Share on other sites
RogerH Posted July 12, 2019 Report Share Posted July 12, 2019 8 minutes ago, ntc said: Roger It is there for the different types of alternators that was fitted,I seem to remember is was for the charging light. N Roger, Have a look here http://www.advanceautowire.com/tr2506.pdf it shows a number of wiring combo's and outlets. Roger Quote Link to post Share on other sites
Pogo Posted July 13, 2019 Author Report Share Posted July 13, 2019 Thanks for the info Gents. The diagram for the 1971 TR6 doesn't show the brown wire (but there is a brown/red one), so I think I'll leave it unconnected like it was on my original wiring. Seems odd to just have a wire unconnected. Rog Quote Link to post Share on other sites
Tim D. Posted July 13, 2019 Report Share Posted July 13, 2019 I have the same thin chopped brown wire on mine. Would be interested in knowing what it was Tim Quote Link to post Share on other sites
RogerH Posted July 13, 2019 Report Share Posted July 13, 2019 Hi Roger, that Red/Brown wire goes directly to a Brown wire !!! Later models do away with the Red/Brown and just have the Brown Roger Quote Link to post Share on other sites
Mike C Posted July 13, 2019 Report Share Posted July 13, 2019 I have a brown and a brown and yellow cut and tied back. I suspect they were need for the original alternator in 1969. Maybe some form of charging control in the days when alternators were replacing generators through the industry. Quote Link to post Share on other sites
RogerH Posted July 13, 2019 Report Share Posted July 13, 2019 Hi Mike, the thin Brown/Yellow is always for the warning light. What are you using.? Roger Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 13, 2019 Report Share Posted July 13, 2019 Something in the voltage control or energising of the alternator perhaps? To do with 'machine sensed' and 'battery sensed' alternator types, according to some Lucas/Unipart blurb I have somewhere. I guess the earlier cars had a battery sensed voltage control or energising circuit, ( the 2 plug alternator TR6 69/70 that has a 2nd wire to the battery connected to the smaller plug ) & later cars + all replacement alternators are now machine sensed voltage control, with the single big plug with 3 terminals (1973 on) Beyond that I can shed no more light. I do know that when fitting some of the Nippon Denso alternators (ex Kubota garden tractor) you need to install an ignition controlled supply to energise it. - More wires! Peter W PS Found on the web - No Responsibility taken for content. "The term is generally applied to alternators, but chargers can be built with remote sensing connections as well. Machine sensed alternators sense the voltage as it appears at the terminals of the alternator. If the battery is some distance away, voltage drop may result in a battery voltage that is noticeably less than the alternator terminal voltage. If Battery isolators are added so that a single alternator can supply more than one battery, then that voltage drop should be compensated for as well. Failure to compensate for drop in a battery isolator can result in undercharging and slow recharging performance. Battery sensed alternator (or charger) regulators have a connection for a sensing wire that can be extended to the battery positive terminal and adjust the alternator output to compensate for the various voltage drops in the positive line. In automotive installations this is satisfactory because distances are normally short and the drop in the chassis returns is minimal. In marine installations and some other installations with long wire runs in both the positive wire and the negative return wiring, even battery sensing will not compensate fully." Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 13, 2019 Report Share Posted July 13, 2019 16 hours ago, Pogo said: Hi All I am still rewiring my TR6 (yes - still!). I have a query. My old wiring had a thin brown wire that was cut off (no connector and not wired to anything), near the alternator. I told Autosparks this when I ordered my new loom (sent them the above picture) and the new loom also has a thin brown wire but it has a spade terminal on it. It seems that the other end goes to the connector block on the inner wing. The alternator wiring has been beefed up (as recommended by Autosparks) and I have replaced the Ammenter with a Voltmeter So - my question is - where does this wire go? Any help much appreciated. Thanks Rog PPS If that spare wire is live, then insulate it. Peter W Quote Link to post Share on other sites
Mike C Posted July 13, 2019 Report Share Posted July 13, 2019 The Brown/Yellow warning light wire is there & works. Maybe the spare B-Y wire was needed on an earlier type of Lucas 15ACR alternator 50 years ago? Quote Link to post Share on other sites
Pogo Posted July 13, 2019 Author Report Share Posted July 13, 2019 (edited) 7 minutes ago, BlueTR3A-5EKT said: PPS If that spare wire is live, then insulate it. Peter W Thanks Peter That is my old set up. The new loom has a plastic sheathed spade terminal and I will tape it up now I know it's not required. Rog Edited July 13, 2019 by Pogo Quote Link to post Share on other sites
Peter V W Posted July 13, 2019 Report Share Posted July 13, 2019 The brown wire was used on the original alternator, when it failed in 1976 the replacement alternator did not require it. I think it was to do with the control unit. Peter V W Quote Link to post Share on other sites
Graham J Posted July 14, 2019 Report Share Posted July 14, 2019 I believe it is some type of exciter or something, I think it triggers the altinator on start up. BUT I do not know this for a fact. i replaced my alternator on my 76 recently, the new alternator did not have a post for this wire. I was told that I could tape it up. Instead, I took the spade of the old alternator and installed it in the same place on the replacement. The spade is not "connected" to anything as it is mounted to plastic, but looks original. The replacement altinator is identical to the original, except with a plain back cover, I replaced this with the original Lucas embossed rear cover. Graham Quote Link to post Share on other sites
stillreel Posted July 18, 2019 Report Share Posted July 18, 2019 I'm thinking it's the engine indicator light or amp meter wire. With the 'new volt meter" using an alternative connection, it may have been what was giving the reading previously. Quote Link to post Share on other sites
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