brake lights staying on constantly

HI, I have a ex mod series 3 109,that having been given a good jet wash recently, now has brake lights that refuse to turn off until I disconnect the battery.It still has the standard military lightswitch with positions for side lights/HST/ etc.. all of which work fine, so Im assuming its a poor earth somewhere(problem is that since the tilt leaked like a sieve, not sure if its inside or underneath somewhere). Any pointers re particular earths to check would be much appreciated.

Isnt the brake light switch mounted in the engine compartment by the brake servo (if yu have one).

hi, yes it is, but the connections are all good/clean.

go in the cab and wedge a brick under the brake pedal to hold it up as far as itll go then see if the brake lights are still on if they are disconnect one of the wires on the servo if they go off you need a new switch ( pennies )

what happens if yu disconnect one wire?
put a multimeter across the switch. is it permanently closed?
try adjusting the switch,

thanks guys, will have a look and come back to you.

Thanks guys, turns out the switch is U/S, although it looked fine externally. Dident help that a new replacement also turned out to be faulty, which caused a bit of head scratching until I put a meter on it (you may have guessed Im not good with electrics!). Many thanks for your help. Phil