Ignition Electrical Issue

[franciscocouto]

MG

Hello everyone, first post here so apologies if it is a bit clunky.

I have an MGB GT from 1979 (see picture no.1). I bought it used in Sept 2024 and used it for about 2 months without many issues. The only main issue I had was the throttle cable kept getting stuck but after some WD40 it pretty much got going normally again.

The car was running fine until around November when I was parking it and all of the sudden it just died out. I turned the ignition on, but absolutely nothing happened. The lights in the dash would turn on, but blinkers and hazard lights would not work. Weirdly, the headlights did work but not much else. The car was fitted with a new electric pump for petrol but that also did not work when turning the key.

After looking around the fuse box, and replacing all of them, nothing seemed to work still. That is when I looked under the dash, and saw some cables that were completely destroyed (see picture no.2).

I also opened the ignition and saw that one of the cables that connects to the ignition had become loose (see picture no.3).

I spoke with my dad who has more experience in cars than I do, and it seemed like an easy fix. I had to basically get a new wiring loom from the ignition to wherever the ignition goes, which leads me to my first problem which is that I have no idea where those cables have to go to.

Me and my dad studied the electrical diagrams but could not find a solution. That is when I reached out to a couple of mechanichs around me, and asked for a diagnostic. I had the car diagnosed by 2 mechanichs and they both told me that this would be a really complicated job, which would take severall weeks and around £2500. This all seemed really expensive and I did not have the budget so right now, the car is not running and parked in a garage.

We are trying to get the car to Portugal but its complicated with tow trucks, so I am writing this message to see if anyone has had a similar issue or if anyone has some advice on what to do. Both mine and my dad experience with cars has been mostly in Portugal where issues like these are usually a lot cheaper to resolve, specially with older cars where the electrics are a lot more basic.

So I guess my questions for you all are:

- Is £2500 an actual reasonable price for this problem? Or am I basically getting scammed?
- If I did have to transport the car to portugal as a non runner, do you have any suggestions on the best way to do it?
- Is there an easier fix to get the car just running so I can drive it some of the way down to Portugal?
- Do you know any mechanics who would be interested in a project like this that can practice a better price?

I truly appreciate everyone's help in advance. As I said, I am still a begginer to older cars, but its a big passion of mine and I want to make sure that I learn and have a good experience. I have had great drives in this car already and would love to see it running again.

Thank you
--

Picture 1
https://drive.google.com/file/d/1BKGurh ... sp=sharing

Picture 2
https://drive.google.com/file/d/1JGBQxN ... drive_link

Picture 3
https://drive.google.com/file/d/1zmM3K8 ... drive_link

Video
https://drive.google.com/file/d/1SnUp6E ... drive_link

[Mrbenn]

Hey,
I can't see the photo's they need permissions to access. But is the damage before or after the main connector coming in under the dashboard? If its after and on the dash loom then £2500 is a lot for the replacement. I've had my B for just over 2 years now and ended up re-wiring the car myself. It's not that daunting if you take your time and follow a wiring diagram for the car.

[Ian F]

I can't see whereabouts you are - in the UK? But if you are in the UK you should try a local MG specialist. They would know the car well and I would think they could repair it for a lot less than that sum.

I don't see why a complete rewire would be necessary.

Ian F

[Bumpa]

I agree with Ian. Tell us where the car currently is. There has to be an MG specialist not too far away. I wouldn't pay £2500 for what is probably a fairly simple wiring fault - these are simple cars. I would get my multimeter out and find out what has happened. Getting it trailered to Portugal is going to cost a load of cash. Fix it if you can.

[Charles Farran]

I agree with Ian & Mike.
These cars have very simple wiring. On a 1979 car there are 3 separate harnesses + a two wire lead from the bottom of the gear lever
to the overdrive switch in the gear lever cap.
The main harness in the engine compartment connects on the inner wing to the gear box harness (that feeds the reverse switch on the side of the gear box & overdrive electrics) & the under chassis harness (that essentially feeds all items at the rear of the car). The main harness supplies all the front lighting & connections to the fuse box, relays , alternator ,coil, distributor, starter motor solenoid / main + supply post on end of solenoid that links to the main + feed cable from the battery.
The main harness feeds through the firewall behind the servo to the interior of the car where it connects with multi connectors to all the instruments & ignition switch.
I haven't seen any pictures , but you suggest that there is evidence of damage to the wiring behind the dash. I also don't know if there is damage elsewhere with the other harnesses.
I don't know what changes you have made to the car since taking ownership & whether the original wiring has been tapered with/ abused by a PO!
The your car (UK Spec 1979) are freely downloadable from the internet in colour that can be blown up to make for easy reading.
Its an exercise of working through circuit by circuit with a multimeter & test bulb to identify where the problems are.
I would recommend "MGB Electrical Systems" by Rick Astley that should assist you greatly, both now & as a future reference book. (Available from many of the usual MG spare suppliers).
Cheers,Charles

[franciscocouto]

Hello everyone.

Thank you so much for your advice thus far.

So in regards to my location, I am currently in Sheffield. In regards to the question by Mrbenn, the damage seems to be after the main connector comes in under the dashboard.

I have visited a local old car specialist and they were the ones who told me £2500. I then asked a diagnostic to an automobile electrician with no specific speciality and he also said around the same sum. If anyone knows who the MG specialist in Sheffield is, or how to find it, please let me know.

I also agree with Ian and Bumpa. It seems like a fairly easy fix, I am just a complete begginer with electrics, and did not want to be messing about. I guess I need to study a lot before I go ahead with anything.

Thank you for all your advice and words Charles. In regards to tampering with the electrical systems, the PO told me that the only thing he did was change the fuel pump. Now after speaking with my dad, the feeling we had was that the PO probablly overloaded the wiring by connecting everything to one single source.

I have made the pictures public, apologies about that. Feel free to have a look to get a bit of a better understanding!

I think we will try and fix it ourselves, its just that we need a space where we can fix it and need to make sure we are doing the right thing. At the moment I just have it on the road which is not ideal, but will get it on a garage very soon.

Cheers,
Francisco

[Charles Farran]

The internet link to the wiring diagrams is :-
www.advanceautowire.com/MGB

Cheers,Charles

[Charles Farran]

Just viewed your photos /video.
Clearly some damage to one /two of the connectors under the dash near the steering column with some wiring adrift / broken / corroded.
At the very least i would be changing the electrical switch part of the steering lock assembly which looks decidedly past its' best.
The part you need is BHA52952 available for £14 - £16 + delivery from MGBhive of MGOC spares to name but two suppliers.
This comes with soldered connections to the ignition switch with the lead to a connector plug that you connect to the main harness socket.
To fit, FIRST DISCONNECT THE BATTERY AT THE BACK OF THE CAR - you then need to unfasten the 3 bolts under the dash holding the steering column, carefully lower the column (until the surround shroud is lower enough to access the screws holding the two halves of the shroud together) & support the column with some strong string / old household cable.
Unscrew the two halves of the shroud, which will then expose the whole steering lock assembly - you will also have to tease out the side /head lamp switch.
With a small cross head (?) screw driver , there is a tiny hole at the bottom of the lock barrel. Remove the small grub screw & you can then remove the electrical switch (after having removed any cable ties holding its' wiring to the column & simply unplug.
Reassemble with the replacement electrical switch etc. ( I did this myself 2 or 3 years ago & found it very easy apart from temporarily supporting the steering column - you may have to slacken off the 3 bolts holding the column where it passes through the bulkhead behind the pedals to give you enough movement of the column).
I would recommend you clean up all the bullet connectors underneath the bonnet including those supplying the front lights as if original , they will be subject to lots of corrosion. Cleaning of the main battery connections , including where the earth strap attaches to the body should also form part of the exercise of getting your car going again!
Cheers,Charles

[franciscocouto]

Thank you everyone for your comments and advice. I truly appreciate it. I think what I will do is get the full wiring loom for the front of the car, and also the the whole ignition with new keys and all the cables done properly (the steering lock was gone so thats 2 birds with one stone). These are the parts I am thinking of getting.

Wiring Loom:
- https://mgbhive.co.uk/product/mgb-gt-ro ... 80-bl-542/

Ignition and Steering Lock
- https://mgbhive.co.uk/product/18-mgb-ru ... k-bhm7144/

I was just going to ask if you know who I can reach out that could possibly just connect the cables to the right spots, and more or less how much that would cost? I know I need to get quotes from auto electricians for a more accurate price, but my last two experiences with diagnostics were really dodgy where I felt I was getting a bit scammed.

Cheers, Francisco

[Charles Farran]

Hi Fransisco,
The wiring loom you have indicated is for the dash harness alone . This plugs into the main harness that comes through the firewall to the
right of the steering wheel , inconveniently close to the windscreen wiper motor.
You refer to getting the "full wiring loom" for the front of the car. From 1976 -77 the wiring at the front was split into two looms - one essentially for
under the bonnet , & the other for behind the dash .
Depending on the state of the 2 looms, then either one or the other or both may need changing. (I can quite understand for peace of mind you may
want to do both)!
A complete change of either is quite arduous when you are starting with a complete car , rather than when everything might have been removed during a restoration exercise.
The harness under the bonnet is the "main harness" & the other one i refer to above is the "dash harness".
I note from your pictures that the car is a "V" reg 1979 car which originally would have been a RB car with the radiator further forward from
that of earlier cars. Yours will have originally have been fitted with an electric cooling fan mounted underneath the slam plate. If the original
fan arrangement is sill there, rather than an after market fan , then the connections to the "main loom" changed between a 1979 & a 1980 harness.
(The earlier harness had pin connectors to the fooling fan , with the later one having spade connectors - the change being after G-HDS-502407).
Obviously if an after market fan has been installed then whichever loom you use will need a slight modification plug/socket wise to attach to the electric fan.
Fitting a new "main harness" requires feeding it through the bulkhead , from the cockpit side, which is best done with one person each side to carefully push & pull the various pieces & joins through to minimise damage.
To fit a new dash harness requires unbolting the dash to get access to the back of the instruments etc. - a very tedious exercise as quite a bit of hardware has to be removed to enable this to be done.
I would recommend you get a copy of the MGB Repair Operation Manual (ROM) Ref AKM4070 - this details how the above should be done & includes some useful pictorial views.
The complete ignition lock assembly you have indicated looks correct. I am not sure what part of it you say is broken "lock wise".
That may become clearer once you remove the cowling as i described in my previous post. If your problem is related to the keys , then they only
affect the operation of the electric part, which may solve the problem you have. If you have to remove the complete lock assembly you will
have to drill out the security bolts fixing the lock to the column as the bolts are designed to have the heads broken on assembly.
Cheers,Charles