Electric fire, smoke behind dashboard. 1981 XJ6 Series 3

Hi, this is my first post in the forums! And for a good reason…

I had an incident where white smoke appeared from the behind the dashboard together with the smell of electrical fire. This is on the left side (steering wheel side, gauge cluster). Smoke is not from the vents, but sip trough from between the dashboard right under the vinyl crash roll.

My thinking is that it’s coming from the fuse box or electrical wiring behind the dashboard…

Any ideas on where to start troubleshooting?

Lucas smoke can be purchased to refill your electrical system Andreas.
Welcome to the forum.

Is the fuse box intact? Check if you see any melted plastic at the tabs that hold the fuses.
I see those iffy pink (of all colours!) cable connectors… these are not very smoke proof to begin with, and seams like someone has fiddled with the electrics, always a worrisome proposition if not done correctly.

I suggest that you remove the dash pad and you will probably find physical evidence of were the smoke escaped.
If not, remove all the fuses (at both left and right fuse boxes) turn the ignition on and start putting (only one each time) each fuse back to try replicate the leak.

FYI, all solid brown colour cables are unswitched +12v.
Brown/second colour are switched +12v .


Do you remember what ancillaries you had turned on while you smelled and saw the smoke - if a wire is too small for the load, the current will heat up the wire and cause the insulation to start to melt and create smoke - if the circuit fuse is bad and did not break open with the extra wire heat (the normal process) then you have the heated wire condition - a heated wire, laying against some insulation, plastic, or paper section would also give the smoke and smell.

You have the dreaded glass tube fuses. On my '83 I once had smoke coming out from under the hood which turned out to be from a fusebox in the engine compartment. The fuses were fine. The problem was underneath the fuse box, where the various wires were connected to the terminals of the fuse box by simple crimping. Crimped connections get corroded, and then the heat generated by poor connections melted the plastic.

The quick fix is to roll the fuse box over and solder all those crimped connections. The better fix is to rip out that glass tube garbage and install a generic replacement fusebox that uses plastic spade fuses.

Indeed, Terry - fuses are there to protect the wires, rated accordingly. If extra load is added to a circuit, exceeding wire capacity; the correctly rated fuse will blow. If higher rated fuses are fitted to ‘cope’ with the extra load - wires will burn…:slight_smile:

Sort of rule of thumb; if the smoke makes your eyes smart - it is burnt insulation. Otherwise, something else is burning…

xj6 85 Sov Europe (UK/NZ)

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Hi and welcome!
Start right at the fuses. But use a 12v supply that turns off (like a weak battery charger) when shorted.

If no fuse is installed and it is still shorted then it is either a brown wire or a part of the wiring before the fuse. In that case you‘re in for disassembly.

If removing all fuses helped and if the fuses look good remove them all and put a test lamp across all four tabs per of the fuse clamps.

From your photo it looks like some of the British rated fuses have been replaced with US (AGC) rated fuses.

the British fuse is marked 25 but actually pops at 25, holds a line current of around 17 amps. So would need to be replaced with a 15 to be safe or maybe a 20 amp US fuse. When it’s replaced with a 25 amp US fuse bad things happen.

British fuse rated at what it pops at, US fuse rated at what it WON’T pop at.

Thanks. I suspect that too, so I checked. Most of them are marked as Lucas, so they should be OK

But a few are not marked, can these perhaps be US version? Not sure how to tell. Attached a photo of one of them.

Thanks. :slight_smile: Working on removing the dashboard now.
I can’t see any obvious signs of fire yet, but there are wires with exposed copper… So that looks very suspicious - but not sure that is what caused the smoke.

And another…

It’s a bit blurry but it looks that either the insulation is melted either it got pinched.
And I think it’s before the fuse, nicht good.
Also the red/yellow cable seems to have a pinch mark as well.

Suspicious to say the least…
What do these lovely pink connectors connect? You should investigate this.

Yes these fuses are the US/modern version.

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Here are a couple of close-ups!
Pinched or melted?

These wires look like someone was doing a test tracing the circuit and cut through the insulation to make contact for the test leads.

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I think it’s the marks of some more pink connectors that have been removed?
You should cut them and rejoint them with solder and shrink-wrap.
The best way to rejoint them is to form a hook on each wire, tin them, hook them together and solder.

Really interesting, learning new stuff, great!

I followed two of the wires from the nice pink connectors with the damaged we wires and they go across the dashboard to the passenger side and end up in a connection to a “box” above the little fuse box.

I have no idea what this box is. Not a standard thing I assume. Any idea what it is?

Oh, that must be the DEFA alarm system?

Ach so ! Nicht gut.

Electric butchery. Those clampon’s aka “vampires”. Nothing but trouble.

Wire solder techniques are many. Some better than others. Aristides’ technique is as goo or better than any.


  1. Strip away about 1/4" on each side of the splice .Slip on abut 3/4" of shrink tape. This applies to method two as well .
    Twist the bare ends together, tightly. with the iron, heat the splice. Apply the solder. It should weep into the splice and form a smooth coating. A solid electrical and mechanical joint. let the splice cool a bit. Slip the tape over it. Apply heat with a heat gun. although a match will do. Miladies hair dryer, sorta, heat gun, oh yeah… . .

  2. Most of the above applies. The difference is the splice. Two finer stands of slightly corroded wire needed. These may or may not be removed. Push the ends of the wire together, each strand parallel to the other, one end in to the other. Secure with the corroded wire. Solder as in # 1. Remove the corroded strands. Purpose served. A bit more tricky than #1. But, smoother. I have a pair of little vices I made to hold the ends in position while I soldered. Wood clothes pins for one and aligator tips for the other. .

Thanks. I’ll give it a try although having very little experience… What are the risks involved with a not perfect job?

Well, hard to make that mess worse!!!

If you are not comfortable with solder.

Cut up some spare wire and practice. It is kinda fun…