Long time no visit! I was driving my Traveller along the Welshpool bypass some time ago when smoke started pouring out of the demister vents. I quickly shut the ignition off, pulled over onto the verge, grabbed an adjustable spanner, popped the bonnet, and disconnected the battery. Peering into the dashboard revealed a lot of blackened wiring and there was oil dripping out onto the floor. Luckily the fire didn't spread, I was in walking distance of my destination and I got a free ride home courtesy of the AA.
Some months later, I've finally got around to working out what caused the fire. A poorly designed TIM ammeter backlight bulb holder. A plastic insulator inside it has split, allowing the live centre electrode to short out to the earthed spring inside. This caused the wire supplying the instrument panel lights to heat up to such an extent that the insulation melted and damaged other nearby wires. It even cut clean through the plastic oil pressure gauge pipe! Unfortunately the wire supplying power from the headlight switch to the instrument light switch, even though they physically only about an inch apart, runs through a section of the wiring loom inside the dashboard that has quite a lot of other important wires in it. The headlight circuit on the Morris Minor isn't protected by a fuse; as I understand it the theory at the time was that you wouldn't want a dodgy fuse to cause your headlights to suddenly fail while speeding along a country lane at night.
(Sorry for the rubbish photo)
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The point of my post is to warn others - if you have any add-on instruments with this type of back-light bulb holder in them, check that the plastic insulator inside is intact, and I would strongly recommend replacing them with one of the plastic Lucas bulb holders instead. They are better designed and far less likely to short out:
http://www.holden.co.uk/displayproduct. ... de=070.037
(I've no connection to this supplier other than sharing a surname with them!)
Dodgy instrument bulb holder - wiring loom fire
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- Minor Legend
- Posts: 3798
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- Location: Burnley
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Dodgy instrument bulb holder - wiring loom fire
Alex Holden - http://www.alexholden.net/
If it doesn't work, you're not hitting it with a big enough hammer.
Re: Dodgy instrument bulb holder - wiring loom fire
I couldn't believe it when I saw your name pop up! Well done for coming back to us to warn us about the problem - and glad to hear you are still Minoring !
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- Minor Legend
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- Location: Whiteabbey, Co Antrim
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Re: Dodgy instrument bulb holder - wiring loom fire
Welcome back Alex!
Too many Minors so little time.....
Re: Dodgy instrument bulb holder - wiring loom fire
What an unmitigated disaster! Bad luck that it should cut through the oil pressure pipe as well - could have been very dodgy.
Maurice, E. Kent
(1970 Traveller)
(1970 Traveller)
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- Minor Legend
- Posts: 3798
- Joined: Tue Jul 25, 2006 9:46 am
- Location: Burnley
- MMOC Member: No
Re: Dodgy instrument bulb holder - wiring loom fire
Loom now repaired by taking it apart, splicing in new wires to replace the ones with melted insulation, and re-wrapping it with fabric loom tape. I've also added a new fusebox with fuses for the lights and for the coil/fuel pump, plus a small inline fuse in the dash protecting the instrument panel backlight circuit. The new solder bullets and bullet connectors proved to be a real pain; they require an unreasonable amount of force to assemble. Managed to take a large gouge out of my finger while trying to shove one in with a screwdriver.
Alex Holden - http://www.alexholden.net/
If it doesn't work, you're not hitting it with a big enough hammer.