qkingston Posted April 25, 2018 Report Share Posted April 25, 2018 Can anyone point me in the direction of a decent resolution wiring diagram for the TR4a that will blow up to A3 size and remain clear? I've not found one in the workshop manual.... Many thanks David Quote Link to post Share on other sites
RogerH Posted April 25, 2018 Report Share Posted April 25, 2018 Hi David, welcome to the forum. TRy this http://www.advanceautowire.com/tr24a.pdf Roger Quote Link to post Share on other sites
qkingston Posted April 25, 2018 Author Report Share Posted April 25, 2018 Thanks Roger, that's great Quote Link to post Share on other sites
Tr4aJim Posted April 26, 2018 Report Share Posted April 26, 2018 Guys, be careful with the Advanced Auto Wire diagram for the TR4a. I (and others) have found some discrepancies, (at least on LHD cars in the US). One regards the lighting switch on the column. Here is how my lighting switch is wired: - switch white/blue to harness double connector with two white/blue wires (going to high beams and high beam dash indicator). This is for momentary high beam flash. - switch brown wire and switch brown/blue wires to harness double connector with brown/blue wire. This goes to 12 volt source. - switch blue wire to harness single connector with blue wire. This goes to the dimmer switch. - switch red/green wire to harness single connector with red/green wire. This goes to fuse block. Note that the AAW diagram also shows a green/brown wire going from the switch to the fuse block. On my car this wire does not exist. My car only has two solid green wires coming out of the fuse block, (to voltage reg and brake lights) as indicated in the AAW diagram. Jim Quote Link to post Share on other sites
ricky30dk Posted January 29, 2019 Report Share Posted January 29, 2019 well that explains a few things......I’d be grateful if you could indicate the other discrepancies - I’m also working on a US model Quote Link to post Share on other sites
Tr4aJim Posted January 30, 2019 Report Share Posted January 30, 2019 Ricky30dk, On my car, the two discrepancies I found (as I mentioned above) were the wiring of the light switch, and nogreen/brown wire from the lighting switch back to the fuse block. I tried to attach an updated wiring diagram I drew of the lighting switch, but when I tried to upload a picture of it, the system said the file was too big. Not sure how to get around that. Jim Quote Link to post Share on other sites
Rktr4a Posted January 31, 2019 Report Share Posted January 31, 2019 Is the diagram for the 4a correct , should it not show a positive earth? Quote Link to post Share on other sites
ianc Posted February 1, 2019 Report Share Posted February 1, 2019 Some years ago, Pete Cox supplied me with a set of wiring diagrams for TR2-4A and another set for TR250-6 (the TR6 has a great many sheets because of the innumerable changes made to suit the American market). The diagram for the TR4A shows negative earth. The set of diagrams for TR2-4A is 116kb, so I cannot upload it here. Ian Cornish Quote Link to post Share on other sites
Tr4aJim Posted February 1, 2019 Report Share Posted February 1, 2019 I fiddled with the image and got the file size down enough to upload. Please bear with my scrawl; those are U’s (blue) and not V’s in the color codes. Also I should have mentioned that mine is a US spec car with negative ground, so I don’t know if that’s the reason for the discrepancies. Jim Quote Link to post Share on other sites
stuart Posted February 1, 2019 Report Share Posted February 1, 2019 The 4a negative or positive earth debate has come up many times on here and still isnt clear, my 4a was definitely positive earth but it was a US model, it seems that the change to negative may well have taken place sometime during the production run but its not documented in spares catalogues or in the workshop manual which normally only shows a TR 4 wiring diagram anyway. Stuart. Quote Link to post Share on other sites
ricky30dk Posted February 1, 2019 Report Share Posted February 1, 2019 Many thanks for your useful comments, all. I have spent some time converting the AAW diagram to an editable format and have this in MS Powerpoint if anyone would like it. I thought it would be useful as I intend to make a number of changes to my wiring. Let's see if I can upload it, but in any case, here's a snapshot of where I'm up to so far. I haven't error checked it yet and I'm still stuck with how to connect the Smartscreen unit, but I wanted to share as it's taken me AGES and involved a lot of swearing......plus one of you might spot some silly mistakes ; ) Also some pics of my modifications - yes, I know it's a TR4 dashboard....it was what I could get at the time.....the hole for the rheostat came in useful though...... TR4A wiring diagram.pptx Quote Link to post Share on other sites
Elliot Fratkin Posted August 9, 2020 Report Share Posted August 9, 2020 Where does positive wire from coil go? Quote Link to post Share on other sites
RobH Posted August 9, 2020 Report Share Posted August 9, 2020 Welcome to the forum Elliot. It isn't clear exactly what your question is about - are you commenting on what has gone before on this thread or do you have a specific problem you need help with? Quote Link to post Share on other sites
peejay4A Posted August 9, 2020 Report Share Posted August 9, 2020 Preempting the answer; if your car is positive earth the positive of the coil goes to the distributor contact breaker connector, and vice versa. Quote Link to post Share on other sites
tthomson Posted August 9, 2020 Report Share Posted August 9, 2020 A slightly different way of looking at the wiring of a TR4A, Attached is the original wiring of my TR4A in PDF format, but I can provide it in SVG, PNG, JPG, and possibly other formats CAR202F_original.pdf Quote Link to post Share on other sites
Giuseppe 988 Posted January 11, 2021 Report Share Posted January 11, 2021 Could someone tell me if the 1967 triumph tr4a cc 2138 engine has the original "ballast" or "non-ballast" coil? Quote Link to post Share on other sites
RobH Posted January 11, 2021 Report Share Posted January 11, 2021 (edited) Welcome to the forum Guiseppe. Ballasted coils were not fitted originally to any of the 4-cylinder cars as far as I know. It seems they were only introduced on TRs from 1974 onwards. Of course it is possible one could have been retro-fitted by an earlier owner, but that should be obvious as there would be an external ballast resistor present. Edited January 11, 2021 by RobH Quote Link to post Share on other sites
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