Dead Speedo

2001 jlx pickup.48000 miles
Background. Because I no longer use the car regularly offroading anymore and effectively only use it for towing a small boat half a dozen times a year, the car only does an annual mileage of 2/300 miles and so every couple of months I remove and recharge the battery.
On the last few occasions when reinstalling the battery a few strange things have happened ie engine (amber)warning light coming on or speedo failing to work, or speedo going to 30mph without car even moving. All of these have generally been resolved just by disconnecting and reconnecting a few times and all runs fine. Yesterday however on reinstalling the battery I got engine light which usual tricks cleared but then the speedo went to 60 and stayed even after disconnecting. Managed to get back to zero by turning ignition on and off ( each time dropping by 10mph until finally reaching zero where it now resides.
Normally on turning ignition on the speedo needle would rise a little from zero to 3or4 mph showing it was alive but now dead .
Removed speedo today and gave gentle shake to see if needle was jammed but made no difference.
Haven't checked under the car as anyone living in the uk will know its a bit wet and breezy today (thanks Brian), is it possible that I have disturbed something reinstalling the battery in the engine bay?

Been a bit wet lately with all these storms and as its been standing idle I reckon the damp has got into the electrics. Try drying the engine bay out after this latest storm passes of course!

Had long experience with this and have to ask you "Does the Tacho still work?" If it does, prob is solved by disconnecting battery and then reconnecting in 20-30 seconds.

Tried the disconnect thing, as you say has worked in the past (several times) but this time continues to play dead. Sorry forgot tacho and all other gauges fine.
As Mickt says poss damp in there somewhere, we have had some seriously crap weather whilst the battery was out and still wet and windy at present.
Car is fine otherwise and certainly driveable will just have to drive by tacho (wonder does it affect the odometer as well?)

Ok break in the weather out with the spanner. Disconnected both sides of the battery instead of just the pos , turned ignition twice to clear static and left for ten minutes.
Reconnected and LIFE. Speedo has re energised although can't test today as traffic is to bad to risk losing parking space. I live next to Twickenham rugby stadium and they are hosting a big American Football game.
At this point no reason to believe all is not well.

When disconnecting a battery always disconnect the earth first! For safety more than anything but it is good practice too!

Yea, pleased that the simplest method has worked. I've been disconnecting the Battery for 10 of the last 17 years to fix the speedo problem. Matter of fact, I have the Tacho marked with the more common speed limits of 80 and 100 kph. No idea why it fixes it, but since it mostly does, I am happy to live with its' little quirks and character. Cheers!

Same for me 16 years but this time it took 3days, clearly ive upset it. Perhaps overheard talk of possible new one?, although as long as it gets thru its annual test it is too useful to me as a general tool to dispose of.

Comment appreciated, I understand what you are saying but for 50 plus years ive done what I do but I am aware of the dangers you mention and take appropriate precautions. Perhaps for younger or inexperienced spanner wealders reading this you could explain more fully.