• The Roadster Factory Recovery Fund - Friends, as you may have heard, The Roadster Factory, a respected British Car Parts business in PA, suffered a total loss in a fire on Christmas Day. Read about it, discuss or ask questions >> HERE. The Triumph Register of America is sponsoring a fund raiser to help TRF get back on their feet. If you can help, vist >> their GoFundMe page.
  • Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

TR2/3/3A Overdrive Wiring

ckeithjordan

Jedi Trainee
Silver
Country flag
Offline
This is primarily for Geo or Barry, but anyone can chime in!

Several years ago, Randall Young (RIP) suggested adding two things to the overdrive circuit: 1) A in-line fuse (AGC 10 or 5) in the brown/white feed from the ammeter and 2) a diode to prevent to help absorb the inductive kickback from the solenoid.

If I understood him correctly on the second part, you would wire the diode at C2 on the relay (in addition to the yellow/purple wire from the solenoid) and a ground point. Is that correct? I was thinking about doing that, with a double spade plug to
accommodate the diode and the Y/P wire, then tie to the screw holding the relay to the battery box underneath. He also said to "point" the diode to ground if +ve or to the relay if -ve. Is there a particular diode current rating I should be considering?

Thanks for any clarification.
 

Geo Hahn

Yoda
Country flag
Offline
Correct,the diode goes from C2 to ground -- of course 'from C2' means anywhere on that yellow/purple wire.

I did it along the way at a connector on the harness, substituting a double bullet for a single bullet:

J84wCaF.jpg


This is the diode I used (though by no means the only choice):

1wIXzkA.jpg


The wiring diagram showing the diode for a positive ground car:

X3F5jIp.jpg


Randall actually installed the diode on top of the solenoid, fitting it inside the rubber cap:

efk42iN.jpg


For the fuse I just put connectors on a fuse holder to fit it between the brown wire and its lug on the relay (C1):

b2NVrSL.jpg


WDomXRw.jpg


All I can offer is 'what I did' - no theory or tech explanation. I just followed Randall's instructions.
 

DavidApp

Yoda
Country flag
Offline
Same here.
This is how I did it. Works so far and the fuse let me know that the solenoid was not switching from pull in to hold in by blowing. Got a new solenoid.


Diode pack s.jpg
The diode I used. It looks smaller physical than Geo's diode.
OD wiring diagram s.jpg
Fuses and Relay.jpg
The 10 amp fuse is for the OD.

David
 

Sarastro

Obi Wan
Silver
Country flag
Offline
Be sure that the cathode of the diode--the end with the line around the diode's body--is connected to the solenoid, with the opposite end grounded. If you get it wrong, you'll find out really fast, but it may take a while to get the burned smell out of the car.
 

Geo Hahn

Yoda
Country flag
Offline
Be sure that the cathode of the diode--the end with the line around the diode's body--is connected to the solenoid, with the opposite end grounded...

That is true if the car is negative ground. The OP has a TR3 which will be positive ground unless it has been changed.
 
OP
ckeithjordan

ckeithjordan

Jedi Trainee
Silver
Country flag
Offline
Yes, my car is negative earth, so the cathode end is pointed to the relay at C2, with the Y/P wire.
 
Similar threads
Thread starter Title Forum Replies Date
luke44 TR2/3/3A Calling all Wiring experts TR3 Overdrive Wiring ver A or ver B or are they the same? Triumph 8
R TR2/3/3A Overdrive wiring installation Triumph 14
S TR2/3/3A Triumph tr3 overdrive wiring Triumph 9
C TR6 TR6 Overdrive Wiring. Triumph 2
S Overdrive Wiring Check Austin Healey 12
Got_All_4 TR2/3/3A Quick Overdrive Wiring Question Triumph 6
BillyB62 TR2/3/3A Type A TR3 Overdrive Wiring Triumph 13
M Stag Wiring plugs for gear lever knob overdrive switch. Triumph 1
Gerry M TR6 Overdrive Wiring Triumph 5
Gerry M TR6 Overdrive Wiring Questions Triumph 10
T TR4/4A Any tips on running the overdrive switch wiring down the steering column? Triumph 11
R TR2/3/3A TR3A Overdrive Wiring Harness Installation Triumph 19
Coyote1 Overdrive wiring question Triumph 8
hondo402000 TR6 Need Help on 71 TR6 Overdrive Wiring Triumph 9
KLUTZ Confused with my Overdrive wiring.. Help please MG 3
R BJ-7 overdrive relay wiring problem Austin Healey 1
A Overdrive wiring Triumph 8
S Overdrive Wiring Austin Healey 2
Mickey Richaud Transmission/Overdrive Wiring MG 3
RickPA Overdrive Oil Pressure Austin Healey 8
bighealeysource Leaking Overdrive and Gearbox Drain Plugs Austin Healey 19
71TR6 TR6 Type-J Overdrive identification Triumph 4
T Wanted Working overdrive unit Austin Healey Classifieds 2
D Overdrive Stops Working After Oil Change Austin Healey 26
S TR2/3/3A overdrive does not function Triumph 45
T TR2/3/3A A type overdrive hard engagement Triumph 28
S Overdrive Throttle Switch Austin Healey 4
KVH General Tech Overdrive--Afraid it's Serious Triumph 45
M Overdrive Pressure Test Austin Healey 2
BN6_2197 Gearbox/Overdrive Removal Austin Healey 25
T For Sale MGB Black Label Overdrive For Sale Or Trade For New RB Parts MG Classifieds 2
Fanch00 Non-Overdrive Benefits? Austin Healey 10
AUSMHLY BJ8 Overdrive Oil Passages Austin Healey 2
R TR6 J-Type overdrive will not disengage when warm Triumph 8
S Overdrive Relays Austin Healey 2
AUSMHLY Overdrive Buffer Pad Austin Healey 3
L Stuck in Overdrive Austin Healey 10
AUSMHLY Flushing the Transmission/Overdrive Austin Healey 7
T Weight of BJ7 Transmission/Overdrive Austin Healey 10
P Overdrive Not Engaging Austin Healey 4
S BJ8 Overdrive Stays Engaged Austin Healey 35
AUSMHLY BJ8 Overdrive Accumulator Spring Tube Austin Healey 1
RonC TR2/3/3A J Type Overdrive in TR3A Triumph 4
AUSMHLY BJ8 Overdrive Pressure Loss Austin Healey 11
AUSMHLY BJ8 Overdrive Oil Pressure Austin Healey 14
John Turney Overdrive Pump Austin Healey 6
S Removing Overdrive Shaft Lever Pin Austin Healey 7
nevets Reversing With Overdrive "On" Austin Healey 8
Healey Nut Overdrive Relay Austin Healey 1
T Clutch or Overdrive Slip Austin Healey 8

Similar threads

Top