Ignition Switch issue

[Tim30]

Hi all

 

I'd be grateful if someone could steer me in the right direction with this.

 

TR4A ('66) - had a new wiring loom a few years back. The car has been dry stored for a couple of years since. Since it had the new loom starting has been an issue. The car only tends to fire after I turn the key and release it (it fires on the release, when the key comes off the start back to "on" - not whilst being turned over on the starter motor itself).

 

I have checked that there is sufficient battery power to fire both the starter motor and the coil - tried two batteries (both in good working order) - made no difference.

 

I've come to the conclusion (rightly or wrongly) that the issue is with the ignition switch wiring itself. Having reviewed plenty of wiring diagrams online I had a look at the wiring on my switch. Assuming the switch is fitted the correct way up, it has the following wiring (this is looking at the switch directly from behind - at the wiring - going clockwise - there is no original numbering but someone over the years has scratched in numbering):

Top - two brown and blue wires (numbered 1)

Right - no wires connected (2) (connections are different shape)

Bottom - one red & white wire and one solid dark green wire (3)

Left - Solid white wires (2 wire on one connection) and solid green wire (4)

 

My thinking is that the white wires which feed power to coil - they are only currently getting power when the switch is in the on position (so car runs ok once started). These wires should be getting power in the on and start positions - and should be attached to the right connections (numbered 2).

 

Should I just switch the white wires and the green wire currently in 4 (left) over to 2 (right)? As you can probably tell, I am complete novice when comes to electrics.... I have also had smoking/burning issues with previous loom (hence new one!) and am totally paranoid about burning this one by tinkering....

 

I've attached a picture hopefully shows above. Thanks very much
Tim

[Steves_TR6]

Perhaps test the switch outof the car with a multimeter, then you'll know what it actually does?

 

It does sound like there is no power getting to the ignition circuit when cranking, only when at 'run' position.

 

this could be wiring, or an incorrect or faulty switch.

 

steve

[ianc]

The wiring diagram in the Workshop Manual shows

- two Brown/Blue to 1,

- two White to 2,

- a Red/White to 3, and

- a Light Green to 4.

I suspect that the two White wires you have to 4 should be to 2.

 

But I agree with Steve that checking your switch with a multimeter would be helpful. And a Workshop Manual (obtainable from the Register's On-line Shop) would be a worthwhile purchase.

 

Ian Cornish

[Tim30]

Many thanks Steve, Ian. Looks like its time to unpack the Multimeter bought many years ago and never used!

Tim

[AlanT]

Forget all that. Just wire battery power direct to the coil, obviously NOT the CB side!

 

If it goes then the switch is wrong. You may be able to dismantle and fix it.

[qkingston]

Recycling an old thread: so if you have a new loom designed for alternator and no control box, is there any change to the ignition switch connection? I assume not as I have the correct number/colour of wires to match the ignition switch terminals as described above by Ian C

Many thanks

David

[RobH]

No change - the only difference is the brown/blue feed to the switch comes direct from the ammeter (if you still have one) rather than via the control box A1 terminal.  Everything else on the switch stays the same.

 

 

 

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Edited October 27, 2021 by RobH
clarification

[qkingston]

Thank Rob, the look was designed for a voltmeter rather than an ammeter (I've read various views on this and I get both sides of the discussion) 

Rgds David