Disco 1 Speedometer interruptus.

'98 D1 300Tdi , the speedometer stopped working after a run along a particularly rough 20klm stretch of bush road last week. Because this has happened before I tried the old trick of pulling out the sender plug on the back of the transfer box between T/C and handbrake drum, cleaning it up and refitting it, this has worked before, not this time. Sometimes the speedo gives a little flicker if you pull left, makes me think it is unplugged somewhere, and maybe effected by the inertia of the vehicles movement, but now even this "flicker" movement has stopped.
Does anyone know the location of all the plug in joints of the wiring to the speedometer, is there another area of common fault where the circuit is lost, even considered a wire could have broken inside the insulation sheathing. Getting tired of using the Garmin for a speedo.

The transducer sounds knackered, had the same problem a replacement cured it.

Either transducer or the connectors, trace the wires back from the transfer box as I think there are two plugs on the loom not including the one into the instrument cluster.

Rodeo Joe said:

The transducer sounds knackered, had the same problem a replacement cured it.

Click to expand...

Yep guess it might be, thing is, it's been doing this trick for the past 7 years and usually only after a hard run on a rough track, previously only had to dodge under and wiggle that plug at the transducer/wiring junction and it was good until the next thrash, that is why I saw it as a disconnected plug or someting like that. A fried transducer would not respond to the wiggle treatment I thought.
I will remove the transducer and have a look, it may be cracked, can borrow a replacement from a wreck out at my mates place.

dieseldog69 said:

Either transducer or the connectors, trace the wires back from the transfer box as I think there are two plugs on the loom not including the one into the instrument cluster.

Click to expand...

Thanks, thought there may have only been a plug in at either end, will check back on wires as well.

When I looked at mine it was pretty rounded off so only making intermittent current to the speedo, go over a big bump and it would briefly spark into life then die again.

Rodeo Joe said:

When I looked at mine it was pretty rounded off so only making intermittent current to the speedo, go over a big bump and it would briefly spark into life then die again.

Click to expand...

You sir get the prize. After many months an update on my Disco speedometer, put the truck up on the hoist to have a look for the problem today, yep, the little drive square section on the back of the signal generator doohickey has rusted a bit and the corners of the square have rounded off, no drive or at least no positive drive.
I was able to prove the generator was still working by putting the drive thingy into a battery drill and spinning it with wiring connected, a mate checked the speedometer on the dash, eureka, it was registering, it worked.
I made a shim sleeve from .005" brass shim and replaced the unit into the transfer case, good result working again, now I can stop using my GPS just as a speedometer.