project 1980 Austin Princess

[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.

[richardthestag]

125/10 for the change to the thread title

 

for radio fitting Staaag also has a non standard hole for the radio

 

two fixes are 

 

https://robsport.co.uk/index.php/online-shop/shop-stag/product/6922-radio-fitting-panel-for-centre-console

 

and

 

https://www.ebay.co.uk/itm/Triumph-Stag-Modern-CD-Radio-Mounting-Fascia-Plate-Black-satin-finish/162956131818?hash=item25f0f13dea:g:Ck4AAOSwU4FaQq-C

 

for the two knob type radio head units you should aready have the bits you need with the old head unit

 

[vulgalour]

That's what used to be fitted and it was rubbish.  You couldn't properly secure it because of the unique (rubbish) way in which the Princess dashboard is made so you just ended up with a head unit that would always wobble and gradually slide off-straight.  I don't want to go back to that.

[richardthestag]

 

what does the dash look like, maybe make up a plate like the top link in my post, secure the corners with nice looking screws of something and make sure the hole is DIN sized

[Mally]

 

 

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?

Correct, just don't overdo it. Works well if the hinge mountings are rust free.

They used a fancy bar to do it on the assembly lines. Probably still do.

[vulgalour]

Richard:  It had a metal plate and braces on the back, it's just a poor design and difficult to keep solid.  Doesn't help that mine's been in and out of the car a bajillion times.

 

May have found something approaching a solution though in the form of this little box that is very close to what I had in mind. https://www.ebay.co.uk/itm/SMSL-SA-36A-Plus-Bluetooth-Digital-Hi-Fi-Stereo-Amplifier-AMP-USB-CoaxialOptical/123048155782

 

It's not terribly expensive and is compact and presumably quite light.  Don't need the Bluetooth functionality so the aerial can go and it would need a different power adaptor but otherwise it's the right sort of thing for what I'd like to do.  Mike's suggestion, that one, on browsing about and trying to find a solution to the imaginary device I've conjured in my head.

[SiC]

That box requires 24v input. Might work on 12v, but might not...

[vulgalour]

The point is, that's more what I have in mind.  So it's a case of figuring out how to build/acquire one suitable for an in-car application.

[Slowsilver]

Hate to rain on your parade, but I don't think the boot lamp switch is the problem or at least not the only problem. The only way a faulty switch by itself could cause a fuse to blow is if it was switching the live supply to the lamp, which it isn't, and shorting to earth.

Since the lamp supply is permanently live (via the fuse) and the switch connects the other side of the lamp to earth to complete the circuit, an open-circuit switch would mean that the light does not come on and a short-circuit switch would mean that the light is on all the time. Neither of these things would blow a correctly-rated fuse if the boot light itself is OK.

If disconnecting the wire from the switch cures the short I would suggest that the problem is with the boot light itself. The only thing which springs to mind immediately is that the lamp has developed a short circuit across the bulb, or the bulb itself is short-circuited, and the switch is not turning off, either because it too is short circuit or more likely not being pressed in enough to be disconnected when the boot is shut. Hence it is the lamp or the bulb which is providing the high-current path to earth and blowing the fuse.

Try removing the bulb from the boot light and measuring the resistance across the bulb. It should be low (a few ohms) but not zero. If it is zero, try another bulb. Also measure the resistance across the bulb contacts with the bulb removed. This should be open circuit. If it low or zero ohms the problem is with the bulb holder.

Good luck!

[vulgalour]

That does make more sense of it.  For now I'm just leaving the boot light disconnected so it's not causing me issues, especially since it's not a vital bit of kit and doesn't really illuminate anything that well when it does work.  We'll fix it properly when/if we upgrade the boot lighting in the future.

[Pillock]

Would this be suitable for tunes? Fifteen quid delivered.

https://www.ebay.co.uk/p/Kentiger-V10-Bluetooth-Hi-fi-Class-ab-Stereo-Super-Bass-Audio-Power-Amplifier/2254345478?iid=361958832265&_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D49131%26meid%3D7c2be3bf6360444d81a1c13403ea99f3%26pid%3D100005%26rk%3D4%26rkt%3D6%26mehot%3Dlo%26sd%3D123048155782%26itm%3D361958832265&_trksid=p2047675.c100005.m1851

 

12V input so powered straight off battery, takes USB and MicroSD (plus Aux input). Has a little display and FANTASTIC KNOBS. Actually looks pleasingly retro.

 

Here's a video of a similar one - some seem to take Aux on the front, some the rear, some are SD and some are Micro SD.

I'm sure you could disable those bloody awful LEDs

[MikeKnight]

12v to 24v isn't so bad, plenty of easily installed converters on eBay for that in various amperage flavours.

 

We looked at some of the 12v ones like above. Any will work really, as long as it has speaker outputs and USB/SD capabilities.