TR2/3/3A Electrical Wiring Best Practices

[DornTRoriginal]

I am moving on to installing heater steering wheel wiring harness and the electrical system, of course there are questions. I have looked over past posts and found some great information, unfortunately I lost the threads with posts and pics from Randall and Geo regarding the use of a small resistors? behind gauges which I would like to see those again as I think these were good additions and would be worth doing if you guys would not mind re-sharing? Sadly this has been a wild journey, I bought the cloth wiring harness from TRF in 1993 (and now it's going in the car yea!), gear reduction starter (2010), alternator conversion kit from Moss (2013) and the gauges have all been restored by Palo Alto Speedometer (2014), an aluminum low profile Fan (12V) Radiator from Wizard Cooling (2012) with relay and wiring harness, now it time to get it done. Presently I am debating the order in which to proceed with installing the dash, heater, wiring and other bits and wondering how it all fits together AND HOPEFULLY I don't need to buy too much more stuff at this point.

What are your suggestions, recommendations and "best practices" for putting all this stuff neatly and safely into the car? Any pictures of installations is welcomed too! Where and what is the connector on the blue wire in the third picture?

I appreciate your input!

 

[CJD]

It's a TR2, but really about the same...starting post 53 for the dash...earlier if you want to follow tub to frame fit.

https://www.britishcarforum.com/bcf/showthread.php?108693-Recipe-for-a-TR2/page2

 

[Kleykamp]

The blue wire is the light socket for the high beam indicator and clips into the back of the speedo.

 

[groupdeville]

Old race car trick: Paint the underside of the cowling bright white. The extra reflectance up under there will assist in seeing what you're doing both at the time of the initial wiring/component install and at the time of repair or replacement work later on.

 

[Geo Hahn]

Everyone will approach this there own way. I had lots of time as the car was in the paint & body for more than a year so I documented the harness I was going to use.

Yeah, I had a wiring diagram and notes on what I had removed (a mess) but this book showed exactly what was in the harness I bought and where it would be connected.

Every wire and its connector were accounted for, line by line. I also made a diagram of the physical layout of the harness (had it spread out on the floor, resisted the urge to sit in the 'driver's seat' and make motor noises):

Methodical to the point of OCD, but like I said - I had the time. When the actual install came around it only took a few hours and everything worked the first time.

I do not recall offhand if your TR uses Lucar (spade) connectors or clamping screws to make the connections. Mine was the latter and I use a bit of solder on the tip of each stripped end. Just a bit on the end to limit fraying but not so much as to create a brittle section at the connection.

BTW my chart shows the solid blue wire goes to the dipper switch (top of left hand page, 1st photo). The one to the light in the speedo is a blue/white (and has a socket on the end).

 

[charleyf]

One method of sorting out all the wires and where they go is to get a variety of color coded plastic ties. I layed out the harness and Using the wiring chart locate each wire and what it goes to. Place a matching color coded tie on each of those. Then when you start installing each item you can look for the colored tie that matches the place you are working on. This is lot less confusing than continually referring to the wiring chart.

 

[TR3driver]

unfortunately I lost the threads with posts and pics from Randall and Geo regarding the use of a small resistors? behind gauges which I would like to see those again as I think these were good additions and would be worth doing if you guys would not mind re-sharing?

I'm not quite certain what you are asking about here. Perhaps the ammeter shunt so you can use the stock ammeter with an alternator (without tearing it up) ?

Otherwise, my only resistors are in the relay circuit to make the rear corner lamps serve triple duty (turn/stop/tail); the fan controller, and the LED lights in the rear.

 

[DavidApp]

Anyone used the modern type of connectors for the head lamps and side lights?

David

This type.
https://www.amazon.com/MUYI-Waterproof-Connector-Superseal-Terminal/dp/B014IU2EE2

 

[CJD]

I'm not quite certain what you are asking about here. Perhaps the ammeter shunt so you can use the stock ammeter with an alternator (without tearing it up) ?

Otherwise, my only resistors are in the relay circuit to make the rear corner lamps serve triple duty (turn/stop/tail); the fan controller, and the LED lights in the rear.

I think he is probably referring to the OD solenoid diode.

 

[DornTRoriginal]

I'm not quite certain what you are asking about here. Perhaps the ammeter shunt so you can use the stock ammeter with an alternator (without tearing it up) ?

Otherwise, my only resistors are in the relay circuit to make the rear corner lamps serve triple duty (turn/stop/tail); the fan controller, and the LED lights in the rear.

What I recall was a small, liner looking thing that had to be installed correctly, one way for positive ground opposite for negative ground, and I think it was to protect the instruments, amp gauge, maybe I am delusional? The suggestion to use an ammeter shunt is interesting, I am using the stock amp meter, ummm anyone installed it? I am thinking the AMP gauge is not going to work the way it did with the generator and I am not sure where I should put the field/instrument wire from the alternator, the Moss how to video indicates it should go to the instrument panel light but TR3s don't have those? The AMP meter seems to be the logical spot. One side of the Amp meter to the alternator the other side to the (negative side) of the Battery? Eliminating all the wires to the regulator but still going to the fuses correct?

Does anyone have a good picture of which holes in the fire wall the wires are to be routed into the engine bay?

 

[TR3driver]

What I recall was a small, liner looking thing that had to be installed correctly, one way for positive ground opposite for negative ground, and I think it was to protect the instruments, amp gauge, maybe I am delusional?

Ah, that would be the diode I added to the OD relay. It helps replacement relays last longer. My original relay went roughly 40 years, but I was having a real problem with replacements failing in just a few months until adding the diode.

The suggestion to use an ammeter shunt is interesting, I am using the stock amp meter, ummm anyone installed it?

I used the stock ammeter with a 60 amp alternator on my previous TR3A for roughly 30 years; worked fine once I added the shunt. Without the shunt, the ammeter needle would bang against the peg at every cold start, which appeared to be slowly damaging the ammeter movement. The needle started sticking against the peg, and wouldn't drop unless I thumped the meter or hit a bump. But with the shunt, it continued working normally and was still doing so when the car got wrecked.

More recently, I put a ~50 amp alternator on my current TR3 (smaller housing, fits much better than the previous one) and saw the same thing.
https://imgur.com/X4GAP8v

I am thinking the AMP gauge is not going to work the way it did with the generator

It can, depending on how you connect the alternator. Many people (including Dan Masters, not sure about Moss) have suggested connecting the alternator so it's output does not pass through the ammeter. That means the ammeter will always show discharge even when the battery is being charged. I like having a functional ammeter, so I went the other way.

and I am not sure where I should put the field/instrument wire from the alternator, the Moss how to video indicates it should go to the instrument panel light but TR3s don't have those?

Sorry, I'm confused again, perhaps partly because I'm not familiar with the Moss video. The 'I' (or in some cases 'L') terminal on the alternator is for the "ignition" warning light on the dash. It must not be connected anywhere else. If you aren't using the warning light, you can either leave it disconnected, or connect a dummy load from it to the ignition circuit. Alternators without a field input (like the Ford Motorcraft I used before) sometimes rely on the current through the lamp to help them get started without having to rev the engine up.

Some alternators include a separate input for field power, which needs to come from a switched power source. On my Denso, it was labeled 'IG' (for ignition) and I wired it to the fuse block (along with the white wire from the ignition switch). Many American alternators don't have this input.

Some alternators include another "sense" input, which should be connected as close to the battery as practical. Labelled 'S' on my Denso, I wired it to the starter solenoid.

Here is a diagram that summarizes the connections

Eliminating all the wires to the regulator but still going to the fuses correct?

Up to you. I used the original control box as a junction block, a convenient place to join the harness wires together with the wires from the alternator. But it serves no other purpose, so can be eliminated if you prefer.

https://imgur.com/Iy4cOxM

 

[DornTRoriginal]

Great Information! Thanks Randall! I think I will try using the old reg box, shunt, relay for fan and wire the starter motor so the starter is powered but there is still the use of the original solenoid, I believe that is similar to what you did, I like it! This electrical part I am finding a bit of a challenge, I accumulated stuff over time without knowing how to install them & then things went weird, too much elapsed time has gone by, now I am trying to put it all together. The alternator I have is a 45 amp and I have converted the pulley and belt so now it just a matter of getting all the wires in the right locations. LED lights are starting to be a consideration too.

Thanks everyone for the help I don't know how I'd get this task completed without everyone's input and the ability to wine every now and then! Mahalo!

 

[DornTRoriginal]

I think he is probably referring to the OD solenoid diode.

You nailed it!

 

[DornTRoriginal]

Methodical to the point of OCD, but like I said - I had the time. When the actual install came around it only took a few hours and everything worked the first time.

I wish I had used a notebook I used little sticky tabs on each wire after 20 plus years they fell off..... go figure!