13 replies to this topic

[aust1n7]

I wonder if someone can help.

I purchased a 1976 1275 GT about 4 years ago, and over the last 12 months, have rebuilt from scratch. I'm not sure of a couple of things, the wiring is my main worry.

 

Question 1 - This might be really simple and stupid question, but can I tell if it is supposed to be a negative or positive earth system from the wiring loom ? I think that the wiring might be a later loom, and there are the 4 switches in the center (headlight, brake fluid test, rear demister and hazard warning lamp) as well as another fog lamp switch under the dash with two other blanks.

 

Question 2 - I'm trying to wire in a fuel pump, which I think is for + earth cars, and I'm not sure if I can use this, and how is the best way to wire it in.

 

PLEASE PLEASE can someone give me advice, or suggest how I can solve this issue. I've put everything back as I found it, but I didn't even check to find out if the battery cable was connected to the + or - terminal.

 

Kindest regards

Tim

[KernowCooper]

Ok here you are Tim

 

Question 1 Your 1275 GT of 1976 would have been a negative earth

 

Question 2 You want a - earth fuel pump, did yours not originally have a mechanical one on the engine

 

The wiring loom you describe is the MK4 loom the same as mine and I have those exact switches, does your dash look like the one below which is the mk3 type with the headlight switch and wipers in the centre and the right hand stalk does indicators and dip/main beam?

 

If so you going to have to do a few mods to the loom to be able to use the standard switches in there position. its not a big job but needs thinking about, and if here in my WS could be done inside a morning easy.

 

Do you have a copy of the Mk3 showing the 1275GT wiring and a copy of the MK4 Mini wiring. if not drop me a PM.

Attached Files

•  1275 dash.jpg   53.6K   18 downloads

Edited by KernowCooper, 29 August 2013 - 11:25 PM.

[Dan]

1976 is the start date for that loom.  If the car has an RVC tacho, it's the right loom.

[Gremlin]

If you want to wire in a positive earth pump into a negative earth loom, just run wires from the battery, with an inline fuse of course, as the battery (if its still in the boot as standard) will be close to the pump, if you have it on the boot floor or on the rear subframe

Don't all shout at once regarding the running wires straight from the battery, but it makes sense in this circumstance

[Yoda]

It needs a fused ignition controlled feed plus preferably a safety cut off switch so wires still need to come from the front of the car!

Edited by Yoda, 30 August 2013 - 08:43 AM.

[Gremlin]

You could mount a switch on the parcel shelf, and you don't NEED a cut off switch, but you could put one in the back

[KernowCooper]

It must be for safety a ignition controlled supply to the fuel pump.

 

The way Paul worded his question Dan I thought he had the 2 switches in the centre so it would take a bit of modifying to adapt the newer loom, when he comes on later we'll get to know his Dash layout.

[aust1n7]

Ok here you are Tim

 

Question 1 Your 1275 GT of 1976 would have been a negative earth

 

Question 2 You want a - earth fuel pump, did yours not originally have a mechanical one on the engine

 

The wiring loom you describe is the MK4 loom the same as mine and I have those exact switches, does your dash look like the one below which is the mk3 type with the headlight switch and wipers in the centre and the right hand stalk does indicators and dip/main beam?

 

If so you going to have to do a few mods to the loom to be able to use the standard switches in there position. its not a big job but needs thinking about, and if here in my WS could be done inside a morning easy.

 

Do you have a copy of the Mk3 showing the 1275GT wiring and a copy of the MK4 Mini wiring. if not drop me a PM.

Hi there, thank you for that reply. No I actually have the 4 switches and the choke and heater on each side. I have all the the plugs that lead to the switches, but I can't for the life of me work out where all of them go. I think I've worked out the main plug for each of the switches, but there are two that go to each side of the switch (apart from the headlight one) and I don't know which side each goes. Does it matter? On on side of the switch, it has the letters AO, does that mean anything?

With regards the fuel pump, yes it did have a mechanical, but it was leaking out of the top and I thought I'd go with the electric type, after reading a few horror stories of the mechanical ones failing and pouring fuel into the oil. I've actually just ordered a new mechanical one as I don't have time to work out the wiring for the electric one, although I'm sure it is simple.

I am trying to get it finished for my wedding day on the 28th Sept, and have stag do tomorrow, so no time then, and only a few weekends in between.

Can you offer any help on the switches?

Kindest

Tim

[aust1n7]

I made a mistake, it was actually registered in Sept 1975. I don't know if that makes a difference.

[aust1n7]

You could mount a switch on the parcel shelf, and you don't NEED a cut off switch, but you could put one in the back

Hi there. Thanks for the response. That was what I was going to do, similar to the way we have the fuel pumps in my austin 7 racer. We just mark it fuel with an obvious on off sign, so if we crash (not something I'm planning on doing in either) we just flick the switch. I have since worked out that it is infact a negaive earth, from the battery connecters, but I still want a very simple switch mech to start the pump before I start the engine. I've put in a fuel regulator anyway, so it shouldn't hose everywhere if left on, I figured it would work the same as the A7 SU pump, it will fill the carbs, and then the valve will stop it filling on the carb lid?? No??

So, if I don't put the mechanical one in straight away, do you think that would work?

Kindest

Tim

Edited by aust1n7, 30 August 2013 - 09:09 PM.

[aust1n7]

It must be for safety a ignition controlled supply to the fuel pump.

 

The way Paul worded his question Dan I thought he had the 2 switches in the centre so it would take a bit of modifying to adapt the newer loom, when he comes on later we'll get to know his Dash layout.

http://farm4.staticf...7fb0c0c8e_m.jpg

http://farm3.staticf...f0b88f298_m.jpg

 

here are the pics of what we are talking about. I don't know if you can make it all out.

[aust1n7]

http://farm3.staticf...f0b88f298_b.jpg

 

thats it a bit larger

Edited by aust1n7, 30 August 2013 - 08:59 PM.

[aust1n7]

http://farm4.staticf...7fb0c0c8e_b.jpg

 

and again

Edited by aust1n7, 30 August 2013 - 09:00 PM.

[KernowCooper]

They are the pilot light wires so when the Hazard Switch is operational it powesr the red segment bulb, can remember which side is which, easy just flick the rocker switch out where the bulb is and the centre pin feed is the Green/ Light Green, its just a piggy back off the main terminal