project 1980 Austin Princess

[chodweaver]

If you say there is still a current draw with all the items disconnected (interior light bulbs removed, cigar lighter disconnected)... pull the fuse, remove the light bulb(s) and disconnect the cigar lighter. Put one probe of your meter on the positive supply at the cigar lighter's plug, the other to a known good earth - behind the dash or bodywork around the seat mounts, handbrake etc. Set the meter to measure resistance - if its showing OL - open circuit, then your problem is not on that wire. Move on to the interior light fitting - remove the bulb - one of the contacts will show a low resistance between it and earth when a door is open - the switch earths that contact to put the bulb on. The other contact of the bulb holder should show OL - if it does not, but shows a resistance of a couple of thousand ohms or less, your partial short to earth is on that wire. Trace the wire to find the bared, chafed or melted bit.

 

(Sorry, if I'm covering old ground.)

 

Sent from my BV6000 using Tapatalk

[vulgalour]

Ben and Chod:  That's what Mike suggested today, more or less.  It's just tedious diagnostics to find the problem now.  At least it's not self-healed, that would be my second least favourite outcome.

[JeeExEll]

Any progress Vulg?

[vulgalour]

Nope.  Today is the first one I've had off in at least 6 weeks so I went into involuntary shutdown mode and have mostly been slobbing about eating biscuits, drinking tea, and watching Russian dashcam vids all day.  It's been... nice?

 

Funny thing though, you know I mentioned about the electricity falling out when waiting at lights?  It did it again.  What's weird is the car _only_ does it at those lights and when I mentioned it to Mike we remembered another car (possibly the Corsa) did the same thing at the same junction.  Perhaps there's something in the area that's interfering with the older, more basic electrics?  Other than that it's been fine, I just haven't had the motivation today to do actual work like scanning wiring diagrams and fettling with wiring, even though I've had the time.

[jon928se]

Wish I had read this thread a bit sooner

 

I recall back in about 1980 - 1982, old man had a 2200 Princess then a 2000 O series, mates dad had a 1700 then 2000 O series All owned from new apart from the 2200. IIRC the oldest one would not have been more than 4 years old when replaced. All of them developed the earth through the accelerator cable condition, one spectacularly so when jump starting it and the cable sheath burst into flames. All cured by replacing the battery earth cable.

 

I learnt to drive in the 2200 and did approx 8000 miles on L plates waiting for a test - 9 months after my 17th birthday, including towing sailing dinghies and driving down to the south of france on holidays. Great motorway cars - the lack of PS contributing to astonishing accuracy at speed.

[purplebargeken]

Just sat here and thought wonder if it is the fusebox itself and that upgrading to a modern one might help. I then scrolled through the more recent posts and saw that was your plan anyway. Now I feel stupid.

[vulgalour]

Don't feel stupid, Ken, it's just a case of great minds thinking alike.

[PhilA]

It's unlikely to be the hand brake warning light circuit. If you had a break under the carpet for that and the wires were touching the body all you'd get would be the warning light on all the time on the dash. That works in the same way as the interior light.

 

Battery - fuse - bulb -------------- switch - body (ground)

 

The longest run of likely pinchable wire on those will just illuminate the bulb and not cause it to pop the fuse.

 

I would start looking at the circuits that don't do light bulb type things first and work backwards towards the fuse.

 

Phil

[JeeExEll]

^ Yes, but remember any live cable coming from fuse 5, or spurred from it, could be shorting to earth (and popping the fuse) at some point BEFORE it actually gets to wherever it's meant to be going.

Regardless of what it's function is.

It will pop the fuse with nothing switched on.

 

At least we have a definite fault at the moment rather than an intermittent one, although that benefit can be lost if things get moved and disturbed. Then the fault might 'go away' for a while. Waiting for the most awkward time to reappear.

[Mally]

Ben's not as stupid as he sometimes tries to be 

[vulgalour]

Had a bit of time today to have a look at this, literally have a look because the multimeter isn't at home and my next free time is Tuesday.  Doesn't do any harm to look for physical damage to the wiring at least, could even tip off where the issue is hiding.  First up, the physical route of the wiring to the rear cigarette lighter.  I'm using the forum uploader because Flickr is currently playing silly buggers.

 

Start behind that dash where it drops down under the carpet.

 

 

This then runs under some heat/soundproof foam with a small tail off to the reverse light switch and ground point.

 

 

After that, it goes under the rear half of the carpet and has tails for the handbrake switch, seatbelt stalks  and passenger seat (warning light on dash operated by switch in seat), and finally to the rear cigarette lighter.

 

 

A physical inspection reveals nothing amiss.  No burning, chafed wires, problems with pierced wiring or trim fixings, nothing pinched.  There's no obvious problem here.  I can't inspect the loom where it goes up into the dashboard without removing the dashboard again which I'm not willing to do today.  The problem remains, of course, as I've not actually fixed anything.  However, even wiggling the wiring around, and isolating the plugs on the wiring loom from anything they might earth on, the problem remains which probably means the issue is somewhere between the dashboard and fusebox.

 

More and more I'm thinking this is a fusebox related issue to be honest.  I did lever the fusebox out of its spot and again there's no obvious signs of any real damage there.  Next step will be to head over to the unit on Tuesday and get the dashboard out again and get the multimeter to work on the loom.  This is a particularly odd problem to me because it's manifested when nothing was repaired, changed or worked on, it's just something that's started happening.  If it had started when I'd, for example, fitted new horns, it would be much easier to grasp what might be at fault.

 

Finally, the wiring diagram I have to work with which, if I'm honest, I do struggle to understand.  If anyone that can read these would like a larger version, I can provide that on request, hopefully this is large enough to view on your screen of choice.

 

[PhilA]

Yeah, agreed it can be before the bulb. However, there's longer runs of more easily accessed wiring that have the capability to run short.

 

Could be something rolling around loose in the fuse box? That's now welded itself across those contacts and blows any fuse fitted?

 

Diagram shows wire splits out at only two main positions after the fuse box and before it is distributed to the circuits. Despite it not showing so, it may come apart at that location allowing things to be disconnected (or become slightly dislodged and touch bodywork). There is a disconnectable plug going to the dome light though. If you find that you could pull it to see if the short is going up to the dome light. Would guess for assembly ease it would be in the footwell area.

 

Phil

[Des]

It's never the interior light wired wrong is it? Watching you from the headlining while you tear out the interior and laughing its cock off.

[JeeExEll]

Ok, had a look at this in my break and made a few notes. Ignore seatbelt gubbins and handbrake switch completely, they're powered from fuse 7.

 

I've deciphered the diagram which looks worse than it is.

 

The only areas we need to concentrate on are

* hazard flasher unit and wiring to switch

* cig lighters front and rear

* interior lamp & switch, front, then wire to each door switch, front only

* interior lamp & switch, rear, then wire to each door switch rear only

* luggage compartment light, then wire to compartment light switch.

 

And that's it. It pretty much confirms what we had at the start, but there was always some uncertainty as to whether or not some other items were involved. Radio should be powered from fuse 1, so if bodgery has been involved there it won't affect fuse 5 circuit.

 

. . . . . . . . . . . . .

Right, if you don't know how to read the diagram Vulg, breathe in, -

Fuse 5 is almost right in the centre of the diagram, a bit below item 11 it's very small and quite faint. It looks like two little circles connected by a horizontal cross. Left side labelled 5 and right side is feed from battery labelled 5u.

 

According to the diagram all, (nearly all) the cables which concern us are purple (surprise surprise).

 

* purple goes to flasher unit (item 42), then light-green & pink to hazard switch (item 20).

 

* purple to cig-lighter front (item 54), then earthed at cig lighter.

Disconnect completely. Is it possible to mix up the push-on connections for cig-lighter and cig-lighter illumination on these? Probably not, would guess they're different sized connectors. Interlinking these circuits could lead to some interesting results, although you still wouldn't have a short circuit to earth,

and

* purp to cig-lighter rear (drawn separately but labelled item 54 too).

 

* purple to interior lamp front (item 64), bulb side, not switch side. Purple & white off to door switches (item 65).

 

* purple to interior lamp rear (item 75), bulb side, purp & white off to door switches (item 76).

 

* purple to boot light (item 82), bulb side, purp & white off to boot switch (item 83).

[JeeExEll]

It's never the interior light wired wrong is it? Watching you from the headlining while you tear out the interior and laughing its cock off.

Plugging the wires into the interior light assembly round the wrong way would do this, yes. Very easy mistake to make. Boot light too. Wouldn't matter if the bulb was in or not. I don't think the boot light is fitted ATM. Don't know if interior lights have been removed / recently replaced, but for some reason I think they're already disconnected.

[vulgalour]

I can tell you the interior light is wired the correct way around, you can't really get it to the incorrect way around and it was working perfectly fine before this fuse issue appeared.  Even unplugging the wires from the interior light and the boot light makes no difference so instead I'll have to see if I can find any other connectors I can disconnect instead.

 

I'm off to the unit in an hour or so and I'll piddle about with things to see if we can resolve this.  I've had purple wire problems on the car before.  At least JeeExEll's post confirms I was understanding the wiring diagram a little bit (in part because of Nomad over on Retrorides helping me read them when he visited that one time).  If there's any plugs for the various sections that concern us on this then they're hidden behind other things, like the dashboard.  That's going to be a little annoying to find.  At least I feel like I am on the right track and haven't been stabbing in the dark completely now.

[PhilA]

With regards to wiring diagrams when troubleshooting stuff like this I found it helpful to photocopy the page and then take a felt tip pen (in the appropriate color) and color in only the circuit I was working on. That much is easy, just trace the lines that join from the fuse, and annotate what's what from the numbers on the diagram.

 

 

Edit:  Like so. Added in the purple/white wires for the interior lights but you disconnected those so it's somewhat academic

Phil

[JeeExEll]

Vulg, use your multimeter on ohms resistance. Disconnect the battery for safety.

 

Keep checking the reading at the fuse holder, between the outgoing live (not incoming battery side which is shown as brown in the diagram) and earth.

 

At the moment with the fault there you'll have a reading of zero ohms. It won't be difficult to track down if the fault's still there. If the fault's cleared you'll get a high resistance reading.

(Don't take resistance readings on live circuits!!).

[JeeExEll]

With regards to wiring diagrams when troubleshooting stuff like this I found it helpful to photocopy the page and then take a felt tip pen (in the appropriate color) and color in only the circuit I was working on. That much is easy, just trace the lines that join from the fuse, and annotate what's what from the numbers on the diagram.

 

Phil

Absolutely. Then as you test each 'line' highlight it in yellow, or whatever, as you go along. Means you only do each bit once.

[vulgalour]

Astonishingly, we didn't get as far as the multimeter.  As you can see in this image, normality, such as it is, has been restored.

 

20180409-01 by Angyl Roper, on Flickr

 

I started off by running through some ideas before getting the multimeter out and disconnecting a few other items.  The door switches were grubby, but fine.  The wiring for the interior light runs near the sunvisor fixings so I removed the relevant fixings just in case it was a hidden wire grounding on a trim screw.  Then moved into the boot, disconnected the wiring from the boot switch again and realised that we'd had to put an extension in from the original loom wire (I can't remember why) and it made me wonder a thing.

20180409-03 by Angyl Roper, on Flickr

 

I haven't got the correct bracket to operate this switch, BL used at least two different switches, brackets and boot rams during production and while I've got an earlier switch and boot rams, I've never had the correct bracket to work between the two.

20180409-02 by Angyl Roper, on Flickr

 

What was strange was that with the wiring disconnected from the switch it never sparked at the fuse.  With it connected, it sometimes sparked at the fuse.  Conclusion, therefore, is that the switch is no good.  Now, I should probably have got the multimeter to action to double-check this but honestly, everything is working precisely as it should now so there seemed no point at all.  All the fuse-5 systems (as usefully highlighted in the diagram above by PhilA) now do what they should, when they should.  Even the hazard switch seems more reliable when before it could be a little hit and miss.  I've fixed this more by luck than anything, really.  Quite what's wrong with the old switch I don't know, I suspect it's just age and possibly corrosion, rather like the  old cigarette lighter which was similarly affected that we had to replace when chasing out the last gremlins.  I'm confident enough to put things  back together when I've next got some time to do so.

 

More frivolously, the boot badges were refitted.  Not a vital thing by any means but I wanted to see if I liked it more with them on or not for a bit.

20180409-04 by Angyl Roper, on Flickr

 

A job for another day is figuring out how to adjust the sag out of the front doors.  It's probably hinge pins but on trying to find play in the hinges today I couldn't, so I'm not 100% sure on that.  The passenger side has been getting steadily worse over the years too.  there's not much adjustment on the doors to take out this sort of sag without replacing the pins, so far as I can work out.

20180409-05 by Angyl Roper, on Flickr

 

20180409-06 by Angyl Roper, on Flickr

 

The driver's door has been bad all the time I've had it, the passenger one only really started getting bad this year.

 

 

[Ghosty]

Looks good with the boot badges on!

[Noel Tidybeard]

just use a std pin switch for the boot and just drill it in like the doors are for simplicity (if you need a boot light that is!)

[MikeKnight]

When I originally extended that boot light switch wiring it did work, just not properly as the boot didn't engage it correctly. I did that at the same time I cleaned up the rear wiring loom which your brother had done good work on but left a bit messy.

 

Looks like the switch itself has internally collapsed, ie the non-conducting divider it has inside which is plastic or ceramic has likely broken apart. Which turns the whole thing into one big grounding point. It happens.

[Des]

That switch should only be able to earth current that's already been through the lamp, might be worth checking the wires there aren't mixed, purple nurple.

Trolley jack and wood block is the best way to cure door sag, with door slightly ajar not fully open or windscreens start popping out.

[vulgalour]

I've just left the boot light disconnected.  It's useless when it is working so I'll be fitting something custom and sorting the wiring out properly when I do that.

 

Trolley-block method is just to jack the door up to the desired location?  Presumably bending the hinge a tiny bit in the desired direction to counteract saggy hinges?

[Tadhg Tiogar]

.... figuring out how to adjust the sag out of the front doors.  It's probably hinge pins but on trying to find play in the hinges today I couldn't, so I'm not 100% sure on that.  The passenger side has been getting steadily worse over the years too.  there's not much adjustment on the doors to take out this sort of sag without replacing the pins, so far as I can work out.

20180409-05 by Angyl Roper, on Flickr

 

20180409-06 by Angyl Roper, on Flickr

 

The driver's door has been bad all the time I've had it, the passenger one only really started getting bad this year.

Is the sheet metal on which the hinges / brackets are attached starting to deform or distort under the weight? I used to see this happen occasionally on E24 Coupé doors, which were heavy, hence sagging out of alignment!

[vulgalour]

With the success of the recent repair*, thoughts turn to another thing I want to fix: tunes.

 

After much consideration, I want to give an MP3 player a go in the Princess rather than a radio-cassette deck.  Partly because more often than not I turn the radio off and drive in silence these days because it's bloody miserable to listen to, partly because very little of my music collection is actually on casette tapes and CDs are a faff in the car.  I want to keep things clean and simple, so I was hoping I could do something like install a USB bank and small MP3 player in the radio hole.  Fitting a radio in the Princess is difficult anyway because of BL using a unique size, so modifying a radio hole blanking plate to accept an MP3 player/USB sockets is going to be a lot easier.

 

Trouble is, on trying to figure this out I'm a bit stuck on what I need to purchase because the options seem to be cheap cigarette lighter plug-in or mega expensive really nice loud sound system.  I want to be somewhere in the middle of these two options.  I'm not after mega volume, just something to break the silence, and I plan to run it through the standard four speaker stereo in the car (2 in the front door cards, 2 in the parcel shelf) which is perfectly adequate for my needs and wants.

[DodgeRover]

What about one of the MP3 adaptor units from ebay that include bluetooth an SD and USB slot? You'll need to run a separate amp as they don't have the output to run anything directly.

Will find an ebay link later.

 

 

Edit like this one

https://m.ebay.co.uk/itm/new-Car-Audio-Bluetooth-USB-SD-TF-MP3-WMA-Board-12V-Wireless-Player-WMA-Speaker/112655170227

[Zelandeth]

Cassette player adaptor to plug an MP3 player into?

 

Sure I've seen an MP3 player built into a cassette casing somewhere too.

[vulgalour]

Dodgerover: That could work, I didn't know they were a thing, but that looks like what I had in mind.  A slightly different version was in the suggested  listings which looks to be a self-contained unit complete with amp built in.  https://www.ebay.co.uk/itm/12V-2CH-200W-Power-Mini-HiFi-Audio-Stereo-AMP-Amplifier-For-ipod-Car-Home-MP3-FM/311431402674 Fitting it is going to be a little awkward compared to the one you showed.

 

Zelandeth:  I've got a couple of casette-to-aux tape adaptors.  I don't use them because there's nowhere to actually put the thing you're plugging in to them without the wires and the device just rolling around and being an nuisance, so I'd like to avoid that.  Also, as mentioned,  fitting a radio-casette in the Princess is a nuisance because it's not a standard size hole and there's no provision for installing a radio cage.