412 / Beaufighter wiring & wiring diagram

[JLucy]

Following my recent post about Beaufighter spares, I'm pleased to say my car is back on the road. Now I'm working on a long list of minor problems, some of which relate to wiring.

I have had various 'issues' with the electrical components of the car over the years. One time I was nearly stranded at the BOC Concours at Brooklands when the car steadfastly refused to start. It turned out that the heavy currents passing through the ignition switch (look at the size of cables to it!) had caused it to fail. On another occasion I found that turning on the heated rear window caused the engine to cut out, which may also relate to the ignition switch. I fitted a new switch, but haven't retried the heated window. The indicators flash too slowly; there seems to be a volts drop on the way to the flasher unit, but I can't find where. The headlight main beam is intermittent; it worked fine for the MOT test, but has now failed again.

As far as I can see there is only one high-current cable leaving the battery positive, and it goes across the car to what I assume is the starter solenoid relay on the bulkhead. There a single heavy-ish, but not huge, brown wire heads back towards the fuses and probably to the ignition switch.

Can anyone point me to a wiring diagram for the Beaufighter? Or even better a workshop manual that included a wiring diagram?

James

[Kevin H]

Originally Posted by JLucy

Can anyone point me to a wiring diagram for the Beaufighter? Or even better a workshop manual that included a wiring diagram?

James

James,
A workshop manual does not exist. I've never seen a wiring diagram either, although I thought someone produced one for the 603 at some stage, which would be very similar.

If the Beaufighter wiring is anything like the 411 wiring then it leaves a bit to be desired, mainly in the form of relays! Ideally almost everything should be on a relay so that there is no significant current flowing through any switches.

Some of the other problems you describe could be earthing issues, which can create some very strange effects on car electrical circuits. Poor earthing can also cause damage because it usually results in current flowing through things it's not meant to flow through!

First of all I would check the point where the battery earth/negative connects to the body. Make sure it is a solid, clean connection. I would also consider running a chunky earth strap to the starter motor or at least the engine (this cured starting problems on my 411).

This might cure some of the issues. If not then you need to then look at each one in detail, paying close attention to the connections, at the accessory itself and the relay if it has one.

NB: I would advise against turning on the rear screen heater again until you have ascertained that it is connected correctly. I believe it is connected via a relay on the 411 so it is likely to be similar on the Beaufighter. It should also have it's own fuse, circa 35Amp.

Let us know how you get on.

Cheers,
Kevin

[Andy603]

James

I had similar problems with my 603, which being of similar vintage may have
bits in common.

The volts to the indicator flasher unit go through the hazard light switch.
All connections to this and the innards need to be clean.

The volts to my headlamps go through the switch, this had been arcing and
the casing had melted. I purchased a replacement switch from BCL, then
subsequently found one at an autojumble for a couple of quid. The main beam
on mine goes through a 26 amp relay by the fuse panel but the switch on the
indicator stalk arcs so may be badly pitted, I always use the footswitch.

Drawings are on the Bristol Owners Club website.


Andy

[browning l]

To assist further in locating these, look in the BOC site, in their Libary section, under 603s.

Here's the site: Member Area - Login

I have downloaded the complete 603 Owner's Manual, as well as a number of the wiring diagrams.

Good luck!

Lou B.

[Kevin H]

There's an online version of the owners manual on this site here . No paid up membership required

Unfortunately no wiring diagrams, but the electrical system could do with some modernisation anyway.

[browning l]

I guess I just assumed that nearly everyone seriously interested in Bristols would be a BOC member.

James, if you would like me to email you any wiring diagrams, just please let me know at mmm@maysvilleky.net, and I'll be more than happy to do so.

Here's a list of what is shown to be available:

Wiring diagrams (PDF thanks to Clive Foster)
Speed Control circuit: SVG/PDF
Headlamp circuits
Side, rear and dash lamps
Foglights & heater
Rear window & gauges
Electric Window Lifts
Boot lid, fuel filler & Sunshine Roof
Fans, horn, clock, lighters & aerial
Seat back adjustment & int. lamps including red warning lamps in door armrests
Wiper motor and wash/wipe: SVG/PDF
Flasher, Hazard, Stop & Reversing lamps and Battery condition indicator
Fuse layout: SVG/PDF
Air conditioning: SVG/PDF
Oil Pressure Unit, Carb Solenoid & electric choke: SVG/PDF
Ignition/starter switch: SVG/PDF/PNG
Alternator voltage control circuitry: SVG/PDF/PNG
Seat-belt drawings (thanks to Graham Bell)
Seat belt assembly
Long End assembly

Lou B.

[browning l]

These are for a 603; obviously they may/may not be of help for you.

[JLucy]

Thanks to all for the extremely helpful replies. I am in fact a BOC member
so I will look at the 603 material there.

I will try to make my own contribution to the sum total of Bristol knowledge
if and when I discover some!

James

[412usa]

James,

I have a factory wiring diagram (original blueprint) for the 412USA but it
may have difference to the Beaufighter and I wouldn't want to lead you
astray with, perhaps devastating consequences.

I suggest you ask the factory for help.

Peter

[browning l]

to the "injured" BOC member who complained about my offer to James.

[Kevin H]

Originally Posted by browning l

to the "injured" BOC member who complained about my offer to James.

Have we missed something?

[Clive Foster]

Originally Posted by Kevin Howard

Have we missed something?

Not that I know of.

However perhaps the "injured" member is unaware that most of those PDF wiring diagram drawings belong to me. They were placed on the BOC site as being probably the easiest place for someone with a serious need to find them. Especially as I have no intention of getting involved in web-site creation, maintenance or any of the other time eating chores beloved of the internet generation.

So far as I'm concerned anyone with a Bristol of suitable type and vintage can use them on the understanding that any errors found or factory installed differences are reported back to me so that I can make relevant changes or add appropriate notes to my master copies. Its worrying that I've never had any reports back of errors or differences. Allegedly I am (was) fairly good at that sort of thing but anyone with drawing office or design experience knows how darn near impossible it is to check your own work. It would also be nice to have the colours for 680040, ..43, ..45, ..92.

Be even nicer to finally get my life back on track enough to dig my 603 out from under the cover and get back to work on it again. Maybe I can at least hope to unwrap those lengths of stainless steel to make some wheel-nuts early next year.

Clive

[browning l]

For your efforts in posting the diagrams on the BOC site.

I have downloaded some of them, and am grateful for their content and your providing them. I do not have any corrections to offer.

I also appreciate your clarification on the ownership of the drawings.

Best wishes,

Lou B.

[Kevin H]

Nice to hear from you Clive, it's been a long time.

If you wish to make your wiring diagrams available to all Bristol owners, rather than only those who are current members of the UK owners club, I would welcome the opportunity to host them in the Resources section of this site.

You could upload them yourself, or email documents to webmaster-at-bristolcars.info and I will upload them.

Regards,
Kevin

[David Olivant]

On the subject of wiring diagrams, does any-one have a diagram which shows
how to wire in the ignition warning light when there is a seperate voltage
contol unit as in the Chrysler set up?
David

[Kevin H]

I just discovered that I have a set of wiring diagrams for the 411. This is likely to be of some use for the 412.

I have uploaded all 13 pages as one PDF file in the resources section under 8cyl cars - 411.

James - I noticed that the rear screen heater is controlled by a relay, which is enabled by the ignition switch, so there's something strange going on if the engine stops when you turn it on!

David, it shows the ignition wiring and Chrysler components but there's no ignition warning lamp that I could see.

[Kevin H]

Clive Foster has kindly made his 603 wiring diagrams available. They are in the Resources section of this site under 8 cyl cars > 603