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TR2/3/3A tr3 wiring harness

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sp53

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Hi all and well I got the tr3 wiring harness in and a special thanks to Don for suggesting to simply just push the wiring harness grommet on and go slow. That was just too simple. I was very intimidated by all the wires and such a small hole in the grommet to get them through, but I just took my time and did them one at a time. My biggest fear was that I could not see how it would be possible to get the grommet over that big crotch of wires and loose ends at the regulator, but it worked out . Anyways I have a couple of questions on the wiring. It just seems like putting three white wires on the one screw terminal at the ignition is too much to ask. It looks like the replacement ignitions have spade terminals making it a little more compatible. And the double large blue and brown wirer coming off the light switch leaves very little wiggle room. In addition, how come the black ground wires are 16 gauge and the others are 14.
Steve
 
sp53 said:
It just seems like putting three white wires on the one screw terminal at the ignition is too much to ask.
Click to expand...
One way around that is to move the white wire for the "ignition" light to the starter pushbutton.<div class="ubbcode-block"><div class="ubbcode-header">Quote:]And the double large blue and brown wirer coming off the light switch leaves very little wiggle room.[/QUOTE]The short section from the light switch to the ignition switch can be (was) a smaller gauge than the harness run. It only carries the current for devices controlled by the ignition switch, while the harness run also carries current for headlights (as well as being much longer).
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] In addition, how come the black ground wires are 16 gauge and the others are 14. [/QUOTE]Not sure which ones you are talking about, but in general they are short and only carry current for one device, so smaller wire is adequate.

Note that "16 gauge" refers to AWG; the original wires were not sized in AWG. The conversions given at https://www.britishwiring.com/CAT02_07.PDF are only approximate.
 
Because I had the harness but not the car (being painted) I used a full-size cardboard mock-up of the dash & center panel to sort things out. Made short work of the actual installation.

wiring3.JPG
 
Well thanks you guys for your help, and Randall I was thinks the same thing about moving the white wire to the starter button but was uncertain. So you are saying to just run the white wire from the fuse box to the starter button? That looks pretty obvious and simple. Well yes the small black wire for wiper ground switch and perhaps the ground for the gas tank. In addition, does the ground for the wiper motor out of the harness go on the stud of the wiper motor base on a later tr3a? The more I work with this wiring harness, I see that the later tr3a has a slightly different diagram than the mid tr3a. Is that right? For example the wiper motor ground and the panel light switch with variable resistance and fuse.
Steve
 
My preference would be to keep the white wire from the fuse box going to the ignition switch, and move the white wire for the ignition lamp to the starter switch. Just one less connection that can reduce power to the coil and wipers. But I don't suppose it makes any real difference.

There are several little variations in the wiring diagrams for different years. If you have the rheostat, this one should be pretty close (except of course showing the connections for RHS instead of LHS)
https://i258.photobucket.com/albums/hh260/TR3driver/TR3AschematicfromPracticalHints6the.jpg
 
I also like to solder the wires that are twinned up together.This makes a more positive connection when the screw is tightened down.Then a dab of di-electric grease and you have banished a lot of gremlins from the system.
MD(mad dog)
 
Like that thought MD, I am working on the wiring the cluster as we type. Shall put that suggestion into action. I can think of a number of places for that grease to go.

Thanks, Tinkerman
 
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